From 5f6d336144b6af368373e80038488e860b28cb7b Mon Sep 17 00:00:00 2001
From: Mohamad Chaarawi <chaarawi@hdfgroup.org>
Date: Tue, 10 Sep 2013 18:02:03 -0500
Subject: [svn-r24122] more transactions/read contexts  - include 2 examples
 for using transactions  - IOD calls at server side still need to be updated

---
 examples/Makefile.am         |    3 +-
 examples/Makefile.in         |    3 +-
 examples/h5ff_client_attr.c  |  311 +++++
 examples/h5ff_client_dset.c  |  294 +++++
 examples/h5ff_client_trans.c |   19 +-
 src/H5FF.c                   |  472 +++++--
 src/H5FFprivate.h            |    3 +-
 src/H5FFpublic.h             |    1 -
 src/H5M.c                    |   56 +-
 src/H5Pdxpl.c                |   13 +
 src/H5RC.c                   |   90 +-
 src/H5RCprivate.h            |   11 +
 src/H5RCpublic.h             |    1 +
 src/H5TR.c                   |   97 +-
 src/H5TRprivate.h            |    3 +-
 src/H5VLiod.c                | 2904 ++++++++++++++++++++++--------------------
 src/H5VLiod_attr.c           |   11 +
 src/H5VLiod_client.c         |  502 ++++----
 src/H5VLiod_client.h         |   53 +-
 src/H5VLiod_common.h         |   32 +-
 src/H5VLiod_dset.c           |    9 +
 src/H5VLiod_dtype.c          |    3 +
 src/H5VLiod_file.c           |   61 +-
 src/H5VLiod_group.c          |    3 +
 src/H5VLiod_link.c           |    9 +
 src/H5VLiod_map.c            |   12 +-
 src/H5VLiod_obj.c            |    8 +
 src/H5VLiod_server.c         |   54 -
 src/H5VLiod_server.h         |    5 -
 src/H5VLiod_trans.c          |   34 +
 30 files changed, 3204 insertions(+), 1873 deletions(-)
 create mode 100644 examples/h5ff_client_attr.c
 create mode 100644 examples/h5ff_client_dset.c

diff --git a/examples/Makefile.am b/examples/Makefile.am
index 7fb18ab..16e3941 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -31,7 +31,8 @@ if BUILD_EFF_CONDITIONAL
   INCLUDES=-I$(top_srcdir)/src -I$(top_srcdir)/test
   LDADD = $(LIBH5TEST) $(LIBHDF5)  $(MYAXE_LIBS) $(MYIOD_LIBS)
   EXAMPLE_PROG_EFF = h5ff_server h5ff_client h5ff_client_map h5ff_client_do \
-                h5ff_client_old_api h5ff_client_multiple_cont h5ff_client_trans
+                h5ff_client_old_api h5ff_client_multiple_cont h5ff_client_trans \
+                h5ff_client_dset h5ff_client_attr
 endif
 
 # Example programs.
diff --git a/examples/Makefile.in b/examples/Makefile.in
index dc56c93..2d57482 100644
--- a/examples/Makefile.in
+++ b/examples/Makefile.in
@@ -402,7 +402,8 @@ CHECK_CLEANFILES = *.chkexe *.chklog *.clog $(EXTLINK_DIRS) *.h5
 @BUILD_PARALLEL_CONDITIONAL_TRUE@LDADD = $(LIBH5TEST) $(LIBHDF5)
 @BUILD_PARALLEL_CONDITIONAL_TRUE@EXAMPLE_PROG_PARA = ph5example
 @BUILD_EFF_CONDITIONAL_TRUE@EXAMPLE_PROG_EFF = h5ff_server h5ff_client h5ff_client_map h5ff_client_do \
-@BUILD_EFF_CONDITIONAL_TRUE@                h5ff_client_old_api h5ff_client_multiple_cont h5ff_client_trans
+@BUILD_EFF_CONDITIONAL_TRUE@                h5ff_client_old_api h5ff_client_multiple_cont h5ff_client_trans \
+@BUILD_EFF_CONDITIONAL_TRUE@                h5ff_client_dset h5ff_client_attr
 
 
 # Example programs.
diff --git a/examples/h5ff_client_attr.c b/examples/h5ff_client_attr.c
new file mode 100644
index 0000000..bf9037f
--- /dev/null
+++ b/examples/h5ff_client_attr.c
@@ -0,0 +1,311 @@
+/* 
+ * h5ff_client_attr.c: Client side test for attribute routines.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+#include "mpi.h"
+#include "hdf5.h"
+
+int main(int argc, char **argv) {
+    const char file_name[]="eff_file.h5";
+
+    hid_t file_id;
+    hid_t gid1;
+    hid_t sid, dtid;
+    hid_t did1;
+    hid_t aid1, aid2, aid3, aid4;
+    hid_t tid1, tid2, rid1, rid2;
+    hid_t fapl_id, trspl_id;
+    hid_t event_q;
+    hbool_t exists1;
+    hbool_t exists2;
+
+    uint64_t version;
+    uint64_t trans_num;
+
+    int *wdata1 = NULL, *wdata2 = NULL;
+    int *rdata1 = NULL, *rdata2 = NULL;
+    const unsigned int nelem=60;
+    hsize_t dims[1];
+
+    int my_rank, my_size;
+    int provided;
+    MPI_Request mpi_req;
+
+    H5_status_t *status = NULL;
+    int num_requests = 0;
+    H5_request_t req1;
+    H5_status_t status1;
+    unsigned int i = 0;
+    herr_t ret;
+
+    MPI_Init_thread(&argc, &argv, MPI_THREAD_MULTIPLE, &provided);
+    if(MPI_THREAD_MULTIPLE != provided) {
+        fprintf(stderr, "MPI does not have MPI_THREAD_MULTIPLE support\n");
+        exit(1);
+    }
+
+    /* Call EFF_init to initialize the EFF stack. */
+    EFF_init(MPI_COMM_WORLD, MPI_INFO_NULL);
+
+    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
+    MPI_Comm_size(MPI_COMM_WORLD, &my_size);
+    fprintf(stderr, "APP processes = %d, my rank is %d\n", my_size, my_rank);
+
+    /* Choose the IOD VOL plugin to use with this file. */
+    fapl_id = H5Pcreate (H5P_FILE_ACCESS);
+    H5Pset_fapl_iod(fapl_id, MPI_COMM_WORLD, MPI_INFO_NULL);
+
+    /* allocate and initialize arrays for dataset I/O */
+    wdata1 = malloc (sizeof(int32_t)*nelem);
+    wdata2 = malloc (sizeof(int32_t)*nelem);
+    rdata1 = malloc (sizeof(int32_t)*nelem);
+    rdata2 = malloc (sizeof(int32_t)*nelem);
+    for(i=0;i<nelem;++i) {
+        rdata1[i] = 0;
+        rdata2[i] = 0;
+        wdata1[i]=i;
+        wdata2[i]=i*2;
+    }
+
+    /* create an event Queue for managing asynchronous requests. */
+    event_q = H5EQcreate(fapl_id);
+    assert(event_q);
+
+    /* create the file. */
+    file_id = H5Fcreate(file_name, H5F_ACC_TRUNC, H5P_DEFAULT, fapl_id);
+    assert(file_id > 0);
+
+    /* create 1-D dataspace with 60 elements */
+    dims [0] = nelem;
+    sid = H5Screate_simple(1, dims, NULL);
+
+    dtid = H5Tcopy(H5T_STD_I32LE);
+
+    /* acquire container version 0 - EXACT */
+    version = 0;
+    rid1 = H5RCacquire(file_id, &version, H5P_DEFAULT, H5_EVENT_QUEUE_NULL);
+    assert(0 == version);
+
+    /* create transaction object */
+    tid1 = H5TRcreate(file_id, rid1, (uint64_t)1);
+    assert(tid1);
+
+    /* start transaction 1 with default num_peers (= 0). 
+       This is asynchronous. */
+    if(0 == my_rank) {
+        ret = H5TRstart(tid1, H5P_DEFAULT, H5_EVENT_QUEUE_NULL);
+        assert(0 == ret);
+    }
+
+    /* Tell other procs that transaction 1 is started */
+    trans_num = 1;
+    MPI_Ibcast(&trans_num, 1, MPI_UINT64_T, 0, MPI_COMM_WORLD, &mpi_req);
+
+    /* Process 0 can continue writing to transaction 1, 
+       while others wait for the bcast to complete */
+    if(0 != my_rank)
+        MPI_Wait(&mpi_req, MPI_STATUS_IGNORE);
+
+    /* create group /G1 */
+    gid1 = H5Gcreate_ff(file_id, "G1", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+    assert(gid1 > 0);
+
+    /* create dataset /G1/D1 */
+    did1 = H5Dcreate_ff(gid1, "D1", dtid, sid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+    assert(did1 > 0);
+
+    /* Commit the datatype dtid to the file. */
+    ret = H5Tcommit_ff(file_id, "DT1", dtid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT, 
+                       tid1, event_q);
+    assert(ret == 0);
+
+    /* create an attribute on root group */
+    aid1 = H5Acreate_ff(file_id, "ROOT_ATTR", dtid, sid, 
+                        H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+    assert(aid1);
+
+    /* create an attribute on group G1. */
+    aid2 = H5Acreate_ff(gid1, "GROUP_ATTR", dtid, sid, 
+                        H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+    assert(aid2);
+
+    /* write data to attributes */
+    ret = H5Awrite_ff(aid1, dtid, wdata1, tid1, event_q);
+    assert(ret == 0);
+    ret = H5Awrite_ff(aid2, dtid, wdata2, tid1, event_q);
+    assert(ret == 0);
+
+    /* Barrier to make sure all processes are done writing so Process
+       0 can finish transaction 1 and acquire a read context on it. */
+    MPI_Barrier(MPI_COMM_WORLD);
+
+    if(0 == my_rank) {
+        MPI_Wait(&mpi_req, MPI_STATUS_IGNORE);
+
+        ret = H5TRfinish(tid1, H5P_DEFAULT, &rid2, H5_EVENT_QUEUE_NULL);
+        assert(0 == ret);
+    }
+
+    /* another barrier so other processes know that container version is acquried */
+    MPI_Barrier(MPI_COMM_WORLD);
+
+    /* Local op */
+    ret = H5TRclose(tid1);
+    assert(0 == ret);
+
+    /* close attribute objects */
+    ret = H5Aclose_ff(aid1, event_q);
+    assert(ret == 0);
+    ret = H5Aclose_ff(aid2, event_q);
+    assert(ret == 0);
+
+    /* release container version 0. This is async. */
+    ret = H5RCrelease(rid1, event_q);
+    assert(0 == ret);
+
+    H5EQwait(event_q, &num_requests, &status);
+    printf("%d requests in event queue. Completions: ", num_requests);
+    for(i=0 ; i<num_requests; i++)
+        fprintf(stderr, "%d ",status[i]);
+    fprintf(stderr, "\n");
+    free(status);
+
+    /* Tell other procs that container version 1 is acquired */
+    version = 1;
+    MPI_Bcast(&version, 1, MPI_UINT64_T, 0, MPI_COMM_WORLD);
+
+    /* other processes just create a read context object; no need to
+       acquire it */
+    if(0 != my_rank) {
+        rid2 = H5RCcreate(file_id, version);
+        assert(rid2 > 0);
+    }
+
+    ret = H5Aexists_ff(file_id, "ROOT_ATTR", &exists1, rid2, event_q);
+    assert(ret == 0);
+    ret = H5Aexists_by_name_ff(file_id, "G1", "GROUP_ATTR", H5P_DEFAULT, &exists2, rid2, event_q);
+    assert(ret == 0);
+
+    aid1 = H5Aopen_ff(file_id, "ROOT_ATTR", H5P_DEFAULT, rid2, event_q);
+    aid2 = H5Aopen_ff(gid1, "GROUP_ATTR", H5P_DEFAULT, rid2, event_q);
+
+    /* read data from datasets with read version 1. */
+    ret = H5Aread_ff(aid1, dtid, rdata1, rid2, event_q);
+    assert(ret == 0);
+    ret = H5Aread_ff(aid2, dtid, rdata2, rid2, event_q);
+    assert(ret == 0);
+
+    /* close attribute objects */
+    ret = H5Aclose_ff(aid1, event_q);
+    assert(ret == 0);
+    ret = H5Aclose_ff(aid2, event_q);
+    assert(ret == 0);
+
+    /* create & start transaction 2 with num_peers = n */
+    tid2 = H5TRcreate(file_id, rid2, (uint64_t)2);
+    assert(tid2);
+    trspl_id = H5Pcreate (H5P_TR_START);
+    ret = H5Pset_trspl_num_peers(trspl_id, my_size);
+    assert(0 == ret);
+    ret = H5TRstart(tid2, trspl_id, event_q);
+    assert(0 == ret);
+    ret = H5Pclose(trspl_id);
+    assert(0 == ret);
+
+    /* Delete an attribute */
+    ret = H5Adelete_ff(file_id, "ROOT_ATTR", tid2, event_q);
+    assert(ret == 0);
+
+    /* rename an attribute */
+    ret = H5Arename_ff(gid1, "GROUP_ATTR", "RENAMED_GROUP_ATTR", tid2, event_q);
+    assert(ret == 0);
+
+    /* create an attribute on dataset */
+    aid3 = H5Acreate_ff(did1, "DSET_ATTR", dtid, sid, 
+                        H5P_DEFAULT, H5P_DEFAULT, tid2, event_q);
+    assert(aid1);
+
+    /* create an attribute on datatype */
+    aid4 = H5Acreate_ff(dtid, "DTYPE_ATTR", dtid, sid, 
+                        H5P_DEFAULT, H5P_DEFAULT, tid2, event_q);
+    assert(aid2);
+
+    /* finish transaction 2 */
+    ret = H5TRfinish(tid2, H5P_DEFAULT, NULL, event_q);
+    assert(0 == ret);
+
+    /* release container version 1. This is async. */
+    ret = H5RCrelease(rid2, event_q);
+    assert(0 == ret);
+
+    /* close objects */
+    ret = H5Aclose_ff(aid3, event_q);
+    assert(ret == 0);
+    ret = H5Aclose_ff(aid4, event_q);
+    assert(ret == 0);
+    ret = H5Dclose_ff(did1, event_q);
+    assert(ret == 0);
+    ret = H5Gclose_ff(gid1, event_q);
+    assert(ret == 0);
+
+    ret = H5Sclose(sid);
+    assert(ret == 0);
+    ret = H5Tclose(dtid);
+    assert(ret == 0);
+    ret = H5Pclose(fapl_id);
+    assert(ret == 0);
+
+    H5Fclose_ff(file_id, event_q);
+
+    H5EQwait(event_q, &num_requests, &status);
+    printf("%d requests in event queue. Completions: ", num_requests);
+    for(i=0 ; i<num_requests; i++)
+        fprintf(stderr, "%d ",status[i]);
+    fprintf(stderr, "\n");
+    free(status);
+
+    ret = H5RCclose(rid1);
+    assert(0 == ret);
+    ret = H5RCclose(rid2);
+    assert(0 == ret);
+    ret = H5TRclose(tid2);
+    assert(0 == ret);
+
+    /* Now we can check operations that were issued previously */
+    if(exists1)
+        printf("Attribute ROOT_ATTR exists!\n");
+    else
+        printf("Errr Attribute ROOT_ATTR does NOT exist. \n");
+
+    if(exists2)
+        printf("Attribute GROUP_ATTR exists!\n");
+    else
+        printf("Errr Attribute GROUP_ATTR does NOT exist. \n");
+
+    fprintf(stderr, "Read Data1: ");
+    for(i=0;i<nelem;++i)
+        fprintf(stderr, "%d ",rdata1[i]);
+    fprintf(stderr, "\n");
+
+    fprintf(stderr, "Read Data2: ");
+    for(i=0;i<nelem;++i)
+        fprintf(stderr, "%d ",rdata2[i]);
+    fprintf(stderr, "\n");
+
+    ret = H5EQclose(event_q);
+    assert(ret == 0);
+
+    free(wdata1);
+    free(wdata2);
+    free(rdata1);
+    free(rdata2);
+
+    EFF_finalize();
+    MPI_Finalize();
+
+    return 0;
+}
diff --git a/examples/h5ff_client_dset.c b/examples/h5ff_client_dset.c
new file mode 100644
index 0000000..8a3e4c6
--- /dev/null
+++ b/examples/h5ff_client_dset.c
@@ -0,0 +1,294 @@
+/* 
+ * h5ff_client_dset.c: Client side test for Dataset routines.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+#include "mpi.h"
+#include "hdf5.h"
+
+int main(int argc, char **argv) {
+    const char file_name[]="eff_file.h5";
+
+    hid_t file_id;
+    hid_t gid1, gid2, gid3;
+    hid_t sid, dtid;
+    hid_t did1, did2, did3;
+    hid_t tid1, tid2, rid1, rid2;
+    hid_t fapl_id, trspl_id;
+    hid_t event_q;
+
+    uint64_t version;
+    uint64_t trans_num;
+
+    int *wdata1 = NULL, *wdata2 = NULL, *wdata3 = NULL;
+    int *rdata1 = NULL, *rdata2 = NULL, *rdata3 = NULL;
+    const unsigned int nelem=60;
+    hsize_t dims[1];
+    hsize_t extent;
+
+    int my_rank, my_size;
+    int provided;
+    MPI_Request mpi_req;
+
+    H5_status_t *status = NULL;
+    int num_requests = 0;
+    H5_request_t req1;
+    H5_status_t status1;
+    unsigned int i = 0;
+    herr_t ret;
+
+    MPI_Init_thread(&argc, &argv, MPI_THREAD_MULTIPLE, &provided);
+    if(MPI_THREAD_MULTIPLE != provided) {
+        fprintf(stderr, "MPI does not have MPI_THREAD_MULTIPLE support\n");
+        exit(1);
+    }
+
+    /* Call EFF_init to initialize the EFF stack. */
+    EFF_init(MPI_COMM_WORLD, MPI_INFO_NULL);
+
+    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
+    MPI_Comm_size(MPI_COMM_WORLD, &my_size);
+    fprintf(stderr, "APP processes = %d, my rank is %d\n", my_size, my_rank);
+
+    /* Choose the IOD VOL plugin to use with this file. */
+    fapl_id = H5Pcreate (H5P_FILE_ACCESS);
+    H5Pset_fapl_iod(fapl_id, MPI_COMM_WORLD, MPI_INFO_NULL);
+
+    /* allocate and initialize arrays for dataset I/O */
+    wdata1 = malloc (sizeof(int32_t)*nelem);
+    wdata2 = malloc (sizeof(int32_t)*nelem);
+    wdata3 = malloc (sizeof(int32_t)*nelem);
+    rdata1 = malloc (sizeof(int32_t)*nelem);
+    rdata2 = malloc (sizeof(int32_t)*nelem);
+    rdata3 = malloc (sizeof(int32_t)*nelem);
+    for(i=0;i<nelem;++i) {
+        rdata1[i] = 0;
+        rdata2[i] = 0;
+        rdata3[i] = 0;
+        wdata1[i]=i;
+        wdata2[i]=i*2;
+        wdata3[i]=i*10;
+    }
+
+    /* create an event Queue for managing asynchronous requests. */
+    event_q = H5EQcreate(fapl_id);
+    assert(event_q);
+
+    /* create the file. */
+    file_id = H5Fcreate(file_name, H5F_ACC_TRUNC, H5P_DEFAULT, fapl_id);
+    assert(file_id > 0);
+
+    /* create 1-D dataspace with 60 elements */
+    dims [0] = nelem;
+    sid = H5Screate_simple(1, dims, NULL);
+
+    dtid = H5Tcopy(H5T_STD_I32LE);
+
+    /* acquire container version 0 - EXACT */
+    version = 0;
+    rid1 = H5RCacquire(file_id, &version, H5P_DEFAULT, H5_EVENT_QUEUE_NULL);
+    assert(0 == version);
+
+    /* create transaction object */
+    tid1 = H5TRcreate(file_id, rid1, (uint64_t)1);
+    assert(tid1);
+
+    /* start transaction 1 with default num_peers (= 0). */
+    if(0 == my_rank) {
+        ret = H5TRstart(tid1, H5P_DEFAULT, H5_EVENT_QUEUE_NULL);
+        assert(0 == ret);
+    }
+
+    /* Tell other procs that transaction 1 is started */
+    trans_num = 1;
+    MPI_Ibcast(&trans_num, 1, MPI_UINT64_T, 0, MPI_COMM_WORLD, &mpi_req);
+
+    /* Process 0 can continue writing to transaction 1, 
+       while others wait for the bcast to complete */
+    if(0 != my_rank)
+        MPI_Wait(&mpi_req, MPI_STATUS_IGNORE);
+
+    /* create group hierarchy /G1/G2/G3 */
+    gid1 = H5Gcreate_ff(file_id, "G1", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+    assert(gid1 > 0);
+    gid2 = H5Gcreate_ff(gid1, "G2", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+    assert(gid2 > 0);
+    gid3 = H5Gcreate_ff(gid2, "G3", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+    assert(gid3 > 0);
+
+    /* create datasets */
+    did1 = H5Dcreate_ff(gid1, "D1", dtid, sid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+    assert(did1 > 0);
+    did2 = H5Dcreate_ff(gid2, "D2", dtid, sid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+    assert(did2 > 0);
+    did3 = H5Dcreate_ff(gid3, "D3", dtid, sid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+    assert(did3 > 0);
+
+    /* write data to datasets */
+    ret = H5Dwrite_ff(did1, dtid, sid, sid, H5P_DEFAULT, wdata1, tid1, event_q);
+    assert(ret == 0);
+    ret = H5Dwrite_ff(did2, dtid, sid, sid, H5P_DEFAULT, wdata2, tid1, event_q);
+    assert(ret == 0);
+    ret = H5Dwrite_ff(did3, dtid, sid, sid, H5P_DEFAULT, wdata3, tid1, event_q);
+    assert(ret == 0);
+
+    /* Barrier to make sure all processes are done writing so Process
+       0 can finish transaction 1 and acquire a read context on it. */
+    MPI_Barrier(MPI_COMM_WORLD);
+
+    if(0 == my_rank) {
+        MPI_Wait(&mpi_req, MPI_STATUS_IGNORE);
+
+        /* make this synchronous so we know the container version has been acquired */
+        ret = H5TRfinish(tid1, H5P_DEFAULT, &rid2, H5_EVENT_QUEUE_NULL);
+        assert(0 == ret);
+    }
+
+    /* another barrier so other processes know that container version is acquried */
+    MPI_Barrier(MPI_COMM_WORLD);
+
+    /* Local op */
+    ret = H5TRclose(tid1);
+    assert(0 == ret);
+
+    /* close some objects */
+    ret = H5Dclose_ff(did1, event_q);
+    assert(ret == 0);
+    ret = H5Gclose_ff(gid1, event_q);
+    assert(ret == 0);
+
+    /* release container version 0. This is async. */
+    ret = H5RCrelease(rid1, event_q);
+    assert(0 == ret);
+
+    H5EQwait(event_q, &num_requests, &status);
+    printf("%d requests in event queue. Completions: ", num_requests);
+    for(i=0 ; i<num_requests; i++)
+        fprintf(stderr, "%d ",status[i]);
+    fprintf(stderr, "\n");
+    free(status);
+
+    /* Tell other procs that container version 1 is acquired */
+    version = 1;
+    MPI_Bcast(&version, 1, MPI_UINT64_T, 0, MPI_COMM_WORLD);
+
+    /* other processes just create a read context object; no need to
+       acquire it */
+    if(0 != my_rank) {
+        rid2 = H5RCcreate(file_id, version);
+        assert(rid2 > 0);
+    }
+
+    /* Open objects closed before */
+    gid1 = H5Gopen_ff(file_id, "G1", H5P_DEFAULT, rid2, event_q);
+    did1 = H5Dopen_ff(file_id, "G1/D1", H5P_DEFAULT, rid2, event_q);
+
+    /* read data from datasets with read version 1. */
+    ret = H5Dread_ff(did1, dtid, sid, sid, H5P_DEFAULT, rdata1, rid2, event_q);
+    assert(ret == 0);
+    ret = H5Dread_ff(did2, dtid, sid, sid, H5P_DEFAULT, rdata2, rid2, event_q);
+    assert(ret == 0);
+    ret = H5Dread_ff(did3, dtid, sid, sid, H5P_DEFAULT, rdata3, rid2, event_q);
+    assert(ret == 0);
+
+    /* create & start transaction 2 with num_peers = n */
+    tid2 = H5TRcreate(file_id, rid2, (uint64_t)2);
+    assert(tid2);
+    trspl_id = H5Pcreate (H5P_TR_START);
+    ret = H5Pset_trspl_num_peers(trspl_id, my_size);
+    assert(0 == ret);
+    ret = H5TRstart(tid2, trspl_id, event_q);
+    assert(0 == ret);
+    ret = H5Pclose(trspl_id);
+    assert(0 == ret);
+
+    extent = 10;
+    ret = H5Dset_extent_ff(did1, &extent, tid2, event_q);
+    assert(ret == 0);
+
+    extent = 30;
+    ret = H5Dset_extent_ff(did2, &extent, tid2, event_q);
+    assert(ret == 0);
+
+    extent = 60;
+    ret = H5Dset_extent_ff(did3, &extent, tid2, event_q);
+    assert(ret == 0);
+
+    /* finish transaction 2 */
+    ret = H5TRfinish(tid2, H5P_DEFAULT, NULL, event_q);
+    assert(0 == ret);
+
+    /* release container version 1. This is async. */
+    ret = H5RCrelease(rid2, event_q);
+    assert(0 == ret);
+
+    /* close objects */
+    ret = H5Dclose_ff(did1, event_q);
+    assert(ret == 0);
+    ret = H5Dclose_ff(did2, event_q);
+    assert(ret == 0);
+    ret = H5Dclose_ff(did3, event_q);
+    assert(ret == 0);
+    ret = H5Gclose_ff(gid1, event_q);
+    assert(ret == 0);
+    ret = H5Gclose_ff(gid2, event_q);
+    assert(ret == 0);
+    ret = H5Gclose_ff(gid3, event_q);
+    assert(ret == 0);
+
+    ret = H5Sclose(sid);
+    assert(ret == 0);
+    ret = H5Tclose(dtid);
+    assert(ret == 0);
+    ret = H5Pclose(fapl_id);
+    assert(ret == 0);
+
+    H5Fclose_ff(file_id, event_q);
+
+    H5EQwait(event_q, &num_requests, &status);
+    printf("%d requests in event queue. Completions: ", num_requests);
+    for(i=0 ; i<num_requests; i++)
+        fprintf(stderr, "%d ",status[i]);
+    fprintf(stderr, "\n");
+    free(status);
+
+    ret = H5RCclose(rid1);
+    assert(0 == ret);
+    ret = H5RCclose(rid2);
+    assert(0 == ret);
+    ret = H5TRclose(tid2);
+    assert(0 == ret);
+
+    fprintf(stderr, "Read Data1: ");
+    for(i=0;i<nelem;++i)
+        fprintf(stderr, "%d ",rdata1[i]);
+    fprintf(stderr, "\n");
+
+    fprintf(stderr, "Read Data2: ");
+    for(i=0;i<nelem;++i)
+        fprintf(stderr, "%d ",rdata2[i]);
+    fprintf(stderr, "\n");
+
+    fprintf(stderr, "Read Data3: ");
+    for(i=0;i<nelem;++i)
+        fprintf(stderr, "%d ",rdata3[i]);
+    fprintf(stderr, "\n");
+
+    ret = H5EQclose(event_q);
+    assert(ret == 0);
+
+    free(wdata1);
+    free(wdata2);
+    free(wdata3);
+    free(rdata1);
+    free(rdata2);
+    free(rdata3);
+
+    EFF_finalize();
+    MPI_Finalize();
+
+    return 0;
+}
diff --git a/examples/h5ff_client_trans.c b/examples/h5ff_client_trans.c
index c92ce3f..7ae0c1c 100644
--- a/examples/h5ff_client_trans.c
+++ b/examples/h5ff_client_trans.c
@@ -64,26 +64,29 @@ int main(int argc, char **argv) {
 
     version = 0;
     /* acquire container version 0 - EXACT */
-    rid1 = H5RCacquire(file_id, &version, H5P_DEFAULT, event_q);
-
-    /* Need to wait for acquire before using it */
-    if(H5EQpop(event_q, &req1) < 0)
-        exit(1);
-    assert(H5AOwait(req1, &status1) == 0);
-    assert (status1);
+    rid1 = H5RCacquire(file_id, &version, H5P_DEFAULT, H5_EVENT_QUEUE_NULL);
 
     /* create 2 transactions objects (does not start transactions). Local call. */
     tid1 = H5TRcreate(file_id, rid1, (uint64_t)1);
     assert(tid1);
-
     tid2 = H5TRcreate(file_id, rid1, (uint64_t)555);
     assert(tid2);
 
     /* start transaction 1 with default num_peers (= 0). 
        This is asynchronous. */
     if(my_rank == 0) {
+        hid_t gid1, gid2;
+
         ret = H5TRstart(tid1, H5P_DEFAULT, event_q);
         assert(0 == ret);
+
+        gid1 = H5Gcreate_ff(file_id, "G1", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+        assert(gid1);
+        gid2 = H5Gcreate_ff(gid1, "G2", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT, tid1, event_q);
+        assert(gid2);
+
+        assert(H5Gclose_ff(gid1, event_q) == 0);
+        assert(H5Gclose_ff(gid2, event_q) == 0);
     }
 
     /* skip transactions 2 till 554. This is asynchronous. */
diff --git a/src/H5FF.c b/src/H5FF.c
index f40818e..2eff89b 100644
--- a/src/H5FF.c
+++ b/src/H5FF.c
@@ -229,56 +229,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5Fflush_ff
- *
- * Purpose:	FF version of H5Fflush()
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Mohamad Chaarawi
- *              April 2013
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5Fflush_ff(hid_t object_id, H5F_scope_t scope, hid_t eq_id)
-{
-    H5VL_t     *vol_plugin;
-    void       *obj;
-    H5I_type_t obj_type;
-    H5VL_loc_params_t loc_params;
-    herr_t      ret_value = SUCCEED;    /* Return value */
-
-    FUNC_ENTER_API(FAIL)
-    H5TRACE3("e", "iFsi", object_id, scope, eq_id);
-
-    obj_type = H5I_get_type(object_id);
-    if(H5I_FILE != obj_type && H5I_GROUP != obj_type && H5I_DATATYPE != obj_type &&
-       H5I_DATASET != obj_type && H5I_ATTR != obj_type) {
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
-    }
-
-    /* get the plugin pointer */
-    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(object_id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
-
-    /* get the file object */
-    if(NULL == (obj = (void *)H5VL_get_object(object_id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
-
-    loc_params.type = H5VL_OBJECT_BY_SELF;
-    loc_params.obj_type = obj_type;
-
-    if((ret_value = H5VL_file_flush(obj, loc_params, vol_plugin, scope, 
-                                    H5AC_dxpl_id, eq_id)) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTFLUSH, FAIL, "unable to flush file")
-
-done:
-    FUNC_LEAVE_API(ret_value)
-} /* end H5Fflush_ff() */
-
-
-/*-------------------------------------------------------------------------
  * Function:	H5Fclose_ff
  *
  * Purpose:	This function closes the file specified by FILE_ID by
@@ -345,9 +295,10 @@ hid_t
 H5Gcreate_ff(hid_t loc_id, const char *name, hid_t lcpl_id, hid_t gcpl_id, hid_t gapl_id,
              hid_t trans_id, hid_t eq_id)
 {
-    void    *grp = NULL;       /* dset token from VOL plugin */
+    void    *grp = NULL;        /* dset token from VOL plugin */
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
     H5VL_loc_params_t loc_params;
     H5P_genplist_t  *plist;            /* Property list pointer */
     hid_t       ret_value;              /* Return value */
@@ -388,6 +339,12 @@ H5Gcreate_ff(hid_t loc_id, const char *name, hid_t lcpl_id, hid_t gcpl_id, hid_t
     if(H5P_set(plist, H5VL_GRP_LCPL_ID, &lcpl_id) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for lcpl id")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     loc_params.type = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type = H5I_get_type(loc_id);
 
@@ -400,7 +357,7 @@ H5Gcreate_ff(hid_t loc_id, const char *name, hid_t lcpl_id, hid_t gcpl_id, hid_t
 
     /* Create the group through the VOL */
     if(NULL == (grp = H5VL_group_create(obj, loc_params, vol_plugin, name, gcpl_id, gapl_id, 
-                                        H5AC_dxpl_id, eq_id)))
+                                        dxpl_id, eq_id)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create group")
 
     /* Get an atom for the group */
@@ -439,6 +396,8 @@ H5Gopen_ff(hid_t loc_id, const char *name, hid_t gapl_id,
     void    *grp = NULL;       /* dset token from VOL plugin */
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     hid_t       ret_value;              /* Return value */
 
@@ -462,14 +421,19 @@ H5Gopen_ff(hid_t loc_id, const char *name, hid_t gapl_id,
     /* get the file object */
     if(NULL == (obj = (void *)H5I_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
-
     /* get the plugin pointer */
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* Create the group through the VOL */
     if(NULL == (grp = H5VL_group_open(obj, loc_params, vol_plugin, name, gapl_id, 
-                                      H5AC_dxpl_id, eq_id)))
+                                      dxpl_id, eq_id)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create group")
 
     /* Get an atom for the group */
@@ -549,6 +513,7 @@ H5Dcreate_ff(hid_t loc_id, const char *name, hid_t type_id, hid_t space_id,
     void    *dset = NULL;       /* dset token from VOL plugin */
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
     H5VL_loc_params_t loc_params;
     H5P_genplist_t  *plist;     /* Property list pointer */
     hid_t       ret_value;              /* Return value */
@@ -596,6 +561,12 @@ H5Dcreate_ff(hid_t loc_id, const char *name, hid_t type_id, hid_t space_id,
     loc_params.type = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type = H5I_get_type(loc_id);
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the file object */
     if(NULL == (obj = (void *)H5VL_get_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
@@ -605,7 +576,7 @@ H5Dcreate_ff(hid_t loc_id, const char *name, hid_t type_id, hid_t space_id,
 
     /* Create the dataset through the VOL */
     if(NULL == (dset = H5VL_dataset_create(obj, loc_params, vol_plugin, name, dcpl_id, dapl_id, 
-                                           H5AC_dxpl_id, eq_id)))
+                                           dxpl_id, eq_id)))
 	HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to create dataset")
 
     /* Get an atom for the dataset */
@@ -643,6 +614,8 @@ H5Dopen_ff(hid_t loc_id, const char *name, hid_t dapl_id, hid_t rcxt_id, hid_t e
     void    *dset = NULL;       /* dset token from VOL plugin */
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     hid_t       ret_value;              /* Return value */
 
@@ -673,9 +646,15 @@ H5Dopen_ff(hid_t loc_id, const char *name, hid_t dapl_id, hid_t rcxt_id, hid_t e
 
     /* Create the dataset through the VOL */
     if(NULL == (dset = H5VL_dataset_open(obj, loc_params, vol_plugin, name, dapl_id, 
-                                         H5AC_dxpl_id, eq_id)))
+                                         dxpl_id, eq_id)))
 	HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to create dataset")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* Get an atom for the dataset */
     if((ret_value = H5I_register2(H5I_DATASET, dset, vol_plugin, TRUE)) < 0)
 	HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to atomize dataset handle")
@@ -709,6 +688,7 @@ H5Dwrite_ff(hid_t dset_id, hid_t mem_type_id, hid_t mem_space_id,
 {
     H5VL_t     *vol_plugin;
     void       *dset;
+    H5P_genplist_t *plist ;     /* Property list pointer */
     herr_t      ret_value;              /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -726,6 +706,12 @@ H5Dwrite_ff(hid_t dset_id, hid_t mem_type_id, hid_t mem_space_id,
         if(TRUE != H5P_isa_class(dxpl_id, H5P_DATASET_XFER))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not xfer parms")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the plugin pointer */
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(dset_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
@@ -763,6 +749,7 @@ H5Dread_ff(hid_t dset_id, hid_t mem_type_id, hid_t mem_space_id,
 {
     H5VL_t     *vol_plugin;
     void       *dset;
+    H5P_genplist_t *plist ;     /* Property list pointer */
     herr_t      ret_value;              /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -786,6 +773,12 @@ H5Dread_ff(hid_t dset_id, hid_t mem_type_id, hid_t mem_space_id,
     if(NULL == (dset = (void *)H5I_object(dset_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid dataset identifier")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* Read the data through the VOL */
     if((ret_value = H5VL_dataset_read(dset, vol_plugin, mem_type_id, mem_space_id, 
                                       file_space_id, dxpl_id, buf, eq_id)) < 0)
@@ -814,6 +807,8 @@ H5Dset_extent_ff(hid_t dset_id, const hsize_t size[], hid_t trans_id, hid_t eq_i
 {
     H5VL_t *vol_plugin;
     void   *dset;
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     herr_t ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -822,6 +817,12 @@ H5Dset_extent_ff(hid_t dset_id, const hsize_t size[], hid_t trans_id, hid_t eq_i
     if(!size)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no size specified")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the plugin pointer */
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(dset_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
@@ -830,7 +831,7 @@ H5Dset_extent_ff(hid_t dset_id, const hsize_t size[], hid_t trans_id, hid_t eq_i
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid dataset identifier")
 
     /* set the extent through the VOL */
-    if((ret_value = H5VL_dataset_set_extent(dset, vol_plugin, size, H5AC_dxpl_id, eq_id)) < 0)
+    if((ret_value = H5VL_dataset_set_extent(dset, vol_plugin, size, dxpl_id, eq_id)) < 0)
 	HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to set extent of dataset")
 
 done:
@@ -909,6 +910,8 @@ H5Tcommit_ff(hid_t loc_id, const char *name, hid_t type_id, hid_t lcpl_id,
     H5T_t   *type = NULL;
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -949,6 +952,12 @@ H5Tcommit_ff(hid_t loc_id, const char *name, hid_t type_id, hid_t lcpl_id,
     loc_params.type = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type = H5I_get_type(loc_id);
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the object from the loc_id */
     if(NULL == (obj = (void *)H5I_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")
@@ -958,7 +967,7 @@ H5Tcommit_ff(hid_t loc_id, const char *name, hid_t type_id, hid_t lcpl_id,
 
     /* commit the datatype through the VOL */
     if (NULL == (dt = H5VL_datatype_commit(obj, loc_params, vol_plugin, name, type_id, lcpl_id, 
-                                           tcpl_id, tapl_id, H5AC_dxpl_id, eq_id)))
+                                           tcpl_id, tapl_id, dxpl_id, eq_id)))
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to commit datatype")
 
     /* attach the vol object created using the commit call to the 
@@ -995,6 +1004,8 @@ H5Topen_ff(hid_t loc_id, const char *name, hid_t tapl_id, hid_t rcxt_id, hid_t e
     void    *vol_dt = NULL;       /* datatype token from VOL plugin */
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5T_t   *dt = NULL;
     H5VL_loc_params_t loc_params;
     hid_t     ret_value = FAIL;      /* Return value */
@@ -1023,9 +1034,15 @@ H5Topen_ff(hid_t loc_id, const char *name, hid_t tapl_id, hid_t rcxt_id, hid_t e
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* Create the datatype through the VOL */
     if(NULL == (vol_dt = H5VL_datatype_open(obj, loc_params, vol_plugin, name, tapl_id, 
-                                        H5AC_dxpl_id, H5_EVENT_QUEUE_NULL)))
+                                        dxpl_id, H5_EVENT_QUEUE_NULL)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to open datatype");
 
     /* Get an atom for the datatype */
@@ -1103,6 +1120,7 @@ H5Acreate_ff(hid_t loc_id, const char *attr_name, hid_t type_id, hid_t space_id,
     void    *attr = NULL;       /* attr token from VOL plugin */
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
     H5P_genplist_t      *plist;            /* Property list pointer */
     H5VL_loc_params_t   loc_params;
     hid_t		ret_value;              /* Return value */
@@ -1134,6 +1152,12 @@ H5Acreate_ff(hid_t loc_id, const char *attr_name, hid_t type_id, hid_t space_id,
     loc_params.type = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type = H5I_get_type(loc_id);
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the file object */
     if(NULL == (obj = (void *)H5VL_get_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid identifier")
@@ -1143,7 +1167,7 @@ H5Acreate_ff(hid_t loc_id, const char *attr_name, hid_t type_id, hid_t space_id,
 
     /* Create the attribute through the VOL */
     if(NULL == (attr = H5VL_attr_create(obj, loc_params, vol_plugin, attr_name, acpl_id, aapl_id, 
-                                        H5AC_dxpl_id, eq_id)))
+                                        dxpl_id, eq_id)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create attribute")
 
     /* Get an atom for the attribute */
@@ -1174,6 +1198,7 @@ H5Acreate_by_name_ff(hid_t loc_id, const char *obj_name, const char *attr_name,
     void    *attr = NULL;       /* attr token from VOL plugin */
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
     H5P_genplist_t      *plist;            /* Property list pointer */
     H5VL_loc_params_t    loc_params;
     hid_t		 ret_value;        /* Return value */
@@ -1209,6 +1234,12 @@ H5Acreate_by_name_ff(hid_t loc_id, const char *obj_name, const char *attr_name,
     loc_params.loc_data.loc_by_name.name = obj_name;
     loc_params.loc_data.loc_by_name.plist_id = lapl_id;
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the file object */
     if(NULL == (obj = (void *)H5VL_get_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
@@ -1219,7 +1250,7 @@ H5Acreate_by_name_ff(hid_t loc_id, const char *obj_name, const char *attr_name,
 
     /* Create the attribute through the VOL */
     if(NULL == (attr = H5VL_attr_create(obj, loc_params, vol_plugin, attr_name, acpl_id, 
-                                        aapl_id, H5AC_dxpl_id, eq_id)))
+                                        aapl_id, dxpl_id, eq_id)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create attribute")
 
     /* Get an atom for the attribute */
@@ -1249,6 +1280,8 @@ H5Aopen_ff(hid_t loc_id, const char *attr_name, hid_t aapl_id,
     void    *attr = NULL;       /* attr token from VOL plugin */
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params; 
     hid_t		ret_value;
 
@@ -1272,8 +1305,14 @@ H5Aopen_ff(hid_t loc_id, const char *attr_name, hid_t aapl_id,
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* Create the attribute through the VOL */
-    if(NULL == (attr = H5VL_attr_open(obj, loc_params, vol_plugin, attr_name, aapl_id, H5AC_dxpl_id, eq_id)))
+    if(NULL == (attr = H5VL_attr_open(obj, loc_params, vol_plugin, attr_name, aapl_id, dxpl_id, eq_id)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to open attribute")
 
     /* Get an atom for the attribute */
@@ -1303,6 +1342,8 @@ H5Aopen_by_name_ff(hid_t loc_id, const char *obj_name, const char *attr_name,
     void    *attr = NULL;       /* attr token from VOL plugin */
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t   loc_params;
     hid_t		ret_value;
 
@@ -1331,13 +1372,18 @@ H5Aopen_by_name_ff(hid_t loc_id, const char *obj_name, const char *attr_name,
     /* get the file object */
     if(NULL == (obj = (void *)H5VL_get_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
-
     /* get the plugin pointer */
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* Create the attribute through the VOL */
-    if(NULL == (attr = H5VL_attr_open(obj, loc_params, vol_plugin, attr_name, aapl_id, H5AC_dxpl_id, eq_id)))
+    if(NULL == (attr = H5VL_attr_open(obj, loc_params, vol_plugin, attr_name, aapl_id, dxpl_id, eq_id)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to open attribute")
 
     /* Get an atom for the attribute */
@@ -1365,6 +1411,8 @@ H5Awrite_ff(hid_t attr_id, hid_t dtype_id, const void *buf, hid_t trans_id, hid_
 {
     H5VL_t     *vol_plugin;
     void       *attr;
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     herr_t ret_value;           /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1374,6 +1422,12 @@ H5Awrite_ff(hid_t attr_id, hid_t dtype_id, const void *buf, hid_t trans_id, hid_
     if(NULL == buf)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "null attribute buffer")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the plugin pointer */
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(attr_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
@@ -1382,7 +1436,7 @@ H5Awrite_ff(hid_t attr_id, hid_t dtype_id, const void *buf, hid_t trans_id, hid_
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid attribute identifier")
 
     /* write the data through the VOL */
-    if((ret_value = H5VL_attr_write(attr, vol_plugin, dtype_id, buf, H5AC_dxpl_id, eq_id)) < 0)
+    if((ret_value = H5VL_attr_write(attr, vol_plugin, dtype_id, buf, dxpl_id, eq_id)) < 0)
 	HGOTO_ERROR(H5E_ATTR, H5E_READERROR, FAIL, "can't read data")
 
 done:
@@ -1403,6 +1457,8 @@ H5Aread_ff(hid_t attr_id, hid_t dtype_id, void *buf, hid_t rcxt_id, hid_t eq_id)
 {
     H5VL_t     *vol_plugin;
     void       *attr;
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     herr_t ret_value;           /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1412,6 +1468,12 @@ H5Aread_ff(hid_t attr_id, hid_t dtype_id, void *buf, hid_t rcxt_id, hid_t eq_id)
     if(NULL == buf)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "null attribute buffer")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* get the plugin pointer */
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(attr_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
@@ -1420,7 +1482,7 @@ H5Aread_ff(hid_t attr_id, hid_t dtype_id, void *buf, hid_t rcxt_id, hid_t eq_id)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid attribute identifier")
 
     /* Read the data through the VOL */
-    if((ret_value = H5VL_attr_read(attr, vol_plugin, dtype_id, buf, H5AC_dxpl_id, eq_id)) < 0)
+    if((ret_value = H5VL_attr_read(attr, vol_plugin, dtype_id, buf, dxpl_id, eq_id)) < 0)
 	HGOTO_ERROR(H5E_ATTR, H5E_READERROR, FAIL, "can't read data")
 
 done:
@@ -1460,11 +1522,19 @@ H5Arename_ff(hid_t loc_id, const char *old_name, const char *new_name,
     if(HDstrcmp(old_name, new_name)) {
         H5VL_t     *vol_plugin;
         void       *obj;
+        hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
         H5VL_loc_params_t loc_params;
 
         loc_params.type = H5VL_OBJECT_BY_SELF;
         loc_params.obj_type = H5I_get_type(loc_id);
 
+        /* store the transaction ID in the dxpl */
+        if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+            HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+        if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
         /* get the file object */
         if(NULL == (obj = (void *)H5VL_get_object(loc_id)))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
@@ -1473,7 +1543,7 @@ H5Arename_ff(hid_t loc_id, const char *old_name, const char *new_name,
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
         /* rename the attribute info through the VOL */
-        if(H5VL_object_misc(obj, loc_params, vol_plugin, H5VL_ATTR_RENAME, H5AC_dxpl_id, 
+        if(H5VL_object_misc(obj, loc_params, vol_plugin, H5VL_ATTR_RENAME, dxpl_id, 
                             eq_id, old_name, new_name) < 0)
             HGOTO_ERROR(H5E_ATTR, H5E_CANTRENAME, FAIL, "can't rename attribute")
     }
@@ -1524,6 +1594,8 @@ H5Arename_by_name_ff(hid_t loc_id, const char *obj_name, const char *old_attr_na
     if(HDstrcmp(old_attr_name, new_attr_name)) {
         H5VL_t     *vol_plugin;
         void       *obj;
+        hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
         H5VL_loc_params_t loc_params;
 
         loc_params.type = H5VL_OBJECT_BY_NAME;
@@ -1531,6 +1603,12 @@ H5Arename_by_name_ff(hid_t loc_id, const char *obj_name, const char *old_attr_na
         loc_params.loc_data.loc_by_name.plist_id = lapl_id;
         loc_params.obj_type = H5I_get_type(loc_id);
 
+        /* store the transaction ID in the dxpl */
+        if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+            HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+        if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
         /* get the file object */
         if(NULL == (obj = (void *)H5VL_get_object(loc_id)))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
@@ -1539,7 +1617,7 @@ H5Arename_by_name_ff(hid_t loc_id, const char *obj_name, const char *old_attr_na
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
         /* rename the attribute info through the VOL */
-        if(H5VL_object_misc(obj, loc_params, vol_plugin, H5VL_ATTR_RENAME, H5AC_dxpl_id, 
+        if(H5VL_object_misc(obj, loc_params, vol_plugin, H5VL_ATTR_RENAME, dxpl_id, 
                             eq_id, old_attr_name, new_attr_name) < 0)
             HGOTO_ERROR(H5E_ATTR, H5E_CANTRENAME, FAIL, "can't rename attribute")
     } /* end if */
@@ -1563,6 +1641,8 @@ H5Adelete_ff(hid_t loc_id, const char *name, hid_t trans_id, hid_t eq_id)
     H5VL_t     *vol_plugin;
     void       *obj;
     H5VL_loc_params_t loc_params;
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     herr_t	ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1577,6 +1657,12 @@ H5Adelete_ff(hid_t loc_id, const char *name, hid_t trans_id, hid_t eq_id)
     loc_params.type = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type = H5I_get_type(loc_id);
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the plugin pointer */
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
@@ -1585,7 +1671,7 @@ H5Adelete_ff(hid_t loc_id, const char *name, hid_t trans_id, hid_t eq_id)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")
 
     /* Open the attribute through the VOL */
-    if(H5VL_attr_remove(obj, loc_params, vol_plugin, name, H5AC_dxpl_id, eq_id) < 0)
+    if(H5VL_attr_remove(obj, loc_params, vol_plugin, name, dxpl_id, eq_id) < 0)
 	HGOTO_ERROR(H5E_ATTR, H5E_CANTDELETE, FAIL, "unable to delete attribute")
 
 done:
@@ -1610,6 +1696,8 @@ H5Adelete_by_name_ff(hid_t loc_id, const char *obj_name, const char *attr_name,
     H5VL_t     *vol_plugin;
     void       *obj;
     H5VL_loc_params_t loc_params;
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     herr_t	ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1633,6 +1721,12 @@ H5Adelete_by_name_ff(hid_t loc_id, const char *obj_name, const char *attr_name,
     loc_params.loc_data.loc_by_name.plist_id = lapl_id;
     loc_params.obj_type = H5I_get_type(loc_id);
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the plugin pointer */
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
@@ -1641,7 +1735,7 @@ H5Adelete_by_name_ff(hid_t loc_id, const char *obj_name, const char *attr_name,
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")
 
     /* Open the attribute through the VOL */
-    if(H5VL_attr_remove(obj, loc_params, vol_plugin, attr_name, H5AC_dxpl_id, eq_id) < 0)
+    if(H5VL_attr_remove(obj, loc_params, vol_plugin, attr_name, dxpl_id, eq_id) < 0)
 	HGOTO_ERROR(H5E_ATTR, H5E_CANTDELETE, FAIL, "unable to delete attribute")
 
 done:
@@ -1669,6 +1763,8 @@ H5Aexists_ff(hid_t obj_id, const char *attr_name, htri_t *ret, hid_t rcxt_id, hi
     H5VL_t     *vol_plugin;
     void       *obj;
     H5VL_loc_params_t loc_params;
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     herr_t	ret_value = SUCCEED;              /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1690,8 +1786,14 @@ H5Aexists_ff(hid_t obj_id, const char *attr_name, htri_t *ret, hid_t rcxt_id, hi
     loc_params.type = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type = H5I_get_type(obj_id);
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* get the attribute info through the VOL */
-    if(H5VL_attr_get(obj, vol_plugin, H5VL_ATTR_EXISTS, H5AC_dxpl_id, eq_id, 
+    if(H5VL_attr_get(obj, vol_plugin, H5VL_ATTR_EXISTS, dxpl_id, eq_id, 
                      loc_params, attr_name, ret) < 0)
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get attribute info")
 
@@ -1720,6 +1822,8 @@ H5Aexists_by_name_ff(hid_t loc_id, const char *obj_name, const char *attr_name,
     H5VL_t     *vol_plugin;
     void       *obj;
     H5VL_loc_params_t loc_params;
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     herr_t	ret_value = SUCCEED;   /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1751,8 +1855,14 @@ H5Aexists_by_name_ff(hid_t loc_id, const char *obj_name, const char *attr_name,
     loc_params.loc_data.loc_by_name.plist_id = lapl_id;
     loc_params.obj_type = H5I_get_type(loc_id);
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* get the attribute info through the VOL */
-    if(H5VL_attr_get(obj, vol_plugin, H5VL_ATTR_EXISTS, H5AC_dxpl_id, eq_id, 
+    if(H5VL_attr_get(obj, vol_plugin, H5VL_ATTR_EXISTS, dxpl_id, eq_id, 
                      loc_params, attr_name, ret) < 0)
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get attribute info")
 
@@ -1829,6 +1939,8 @@ H5Lmove_ff(hid_t src_loc_id, const char *src_name, hid_t dst_loc_id,
     void    *obj2 = NULL;        /* object token of dst_id */
     H5VL_t  *vol_plugin2;        /* VOL plugin information */
     H5VL_loc_params_t loc_params2;
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     herr_t      ret_value=SUCCEED;              /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1885,10 +1997,16 @@ H5Lmove_ff(hid_t src_loc_id, const char *src_name, hid_t dst_loc_id,
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "Objects are accessed through different VOL plugins and can't be linked")
     }
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* Move the link through the VOL */
     if((ret_value = H5VL_link_move(obj1, loc_params1, obj2, loc_params2, 
                                    (vol_plugin1!=NULL ? vol_plugin1 : vol_plugin2), 
-                                   FALSE, lcpl_id, lapl_id, H5AC_dxpl_id, eq_id)) < 0)
+                                   FALSE, lcpl_id, lapl_id, dxpl_id, eq_id)) < 0)
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create link")
 
 done:
@@ -1920,6 +2038,8 @@ H5Lcopy_ff(hid_t src_loc_id, const char *src_name, hid_t dst_loc_id,
     void    *obj2 = NULL;        /* object token of dst_id */
     H5VL_t  *vol_plugin2;        /* VOL plugin information */
     H5VL_loc_params_t loc_params2;
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     herr_t      ret_value=SUCCEED;              /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1976,10 +2096,16 @@ H5Lcopy_ff(hid_t src_loc_id, const char *src_name, hid_t dst_loc_id,
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "Objects are accessed through different VOL plugins and can't be linked")
     }
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* Move the link through the VOL */
     if((ret_value = H5VL_link_move(obj1, loc_params1, obj2, loc_params2, 
                                    (vol_plugin1!=NULL ? vol_plugin1 : vol_plugin2), 
-                                   TRUE, lcpl_id, lapl_id, H5AC_dxpl_id, eq_id)) < 0)
+                                   TRUE, lcpl_id, lapl_id, dxpl_id, eq_id)) < 0)
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create link")
 done:
     FUNC_LEAVE_API(ret_value)
@@ -2010,6 +2136,7 @@ H5Lcreate_soft_ff(const char *link_target, hid_t link_loc_id, const char *link_n
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
     H5VL_loc_params_t loc_params;
     H5P_genplist_t *plist;      /* Property list pointer */
     herr_t      ret_value = SUCCEED;    /* Return value */
@@ -2040,6 +2167,12 @@ H5Lcreate_soft_ff(const char *link_target, hid_t link_loc_id, const char *link_n
     loc_params.loc_data.loc_by_name.plist_id = lapl_id;
     loc_params.obj_type = H5I_get_type(link_loc_id);
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the file object */
     if(NULL == (obj = (void *)H5I_object(link_loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
@@ -2057,7 +2190,7 @@ H5Lcreate_soft_ff(const char *link_target, hid_t link_loc_id, const char *link_n
 
     /* Create the link through the VOL */
     if((ret_value = H5VL_link_create(H5VL_LINK_CREATE_SOFT, obj, loc_params, vol_plugin,
-                                     lcpl_id, lapl_id, H5AC_dxpl_id, eq_id)) < 0)
+                                     lcpl_id, lapl_id, dxpl_id, eq_id)) < 0)
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create link")
 
 done:
@@ -2093,6 +2226,7 @@ H5Lcreate_hard_ff(hid_t cur_loc_id, const char *cur_name, hid_t new_loc_id,
     H5VL_loc_params_t loc_params1;
     H5VL_loc_params_t loc_params2;
     H5P_genplist_t *plist;      /* Property list pointer */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
     herr_t   ret_value = SUCCEED;            /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -2158,10 +2292,16 @@ H5Lcreate_hard_ff(hid_t cur_loc_id, const char *cur_name, hid_t new_loc_id,
     if(H5P_set(plist, H5VL_LINK_TARGET_LOC_PARAMS, &loc_params1) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for target name")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* Create the link through the VOL */
     if((ret_value = H5VL_link_create(H5VL_LINK_CREATE_HARD, obj2, loc_params2, 
                                      (vol_plugin1!=NULL ? vol_plugin1 : vol_plugin2),
-                                     lcpl_id, lapl_id, H5AC_dxpl_id, eq_id)) < 0)
+                                     lcpl_id, lapl_id, dxpl_id, eq_id)) < 0)
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create link")
 
 done:
@@ -2191,6 +2331,8 @@ H5Ldelete_ff(hid_t loc_id, const char *name, hid_t lapl_id, hid_t trans_id, hid_
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -2206,6 +2348,12 @@ H5Ldelete_ff(hid_t loc_id, const char *name, hid_t lapl_id, hid_t trans_id, hid_
     loc_params.loc_data.loc_by_name.name = name;
     loc_params.loc_data.loc_by_name.plist_id = lapl_id;
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the file object */
     if(NULL == (obj = (void *)H5I_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
@@ -2214,7 +2362,7 @@ H5Ldelete_ff(hid_t loc_id, const char *name, hid_t lapl_id, hid_t trans_id, hid_
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
     /* Delete the link through the VOL */
-    if((ret_value = H5VL_link_remove(obj, loc_params, vol_plugin, H5AC_dxpl_id, 
+    if((ret_value = H5VL_link_remove(obj, loc_params, vol_plugin, dxpl_id, 
                                      eq_id)) < 0)
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create link")
 
@@ -2242,6 +2390,8 @@ H5Lexists_ff(hid_t loc_id, const char *name, hid_t lapl_id, htri_t *ret,
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t ret_value = SUCCEED;
 
@@ -2269,9 +2419,15 @@ H5Lexists_ff(hid_t loc_id, const char *name, hid_t lapl_id, htri_t *ret,
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* check link existence through the VOL */
     if(H5VL_link_get(obj, loc_params, vol_plugin, H5VL_LINK_EXISTS, 
-                     H5AC_dxpl_id, eq_id, ret) < 0)
+                     dxpl_id, eq_id, ret) < 0)
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get link info")
 
 done:
@@ -2298,6 +2454,8 @@ H5Lget_info_ff(hid_t loc_id, const char *name, H5L_ff_info_t *linfo /*out*/,
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t ret_value = SUCCEED;
 
@@ -2324,9 +2482,15 @@ H5Lget_info_ff(hid_t loc_id, const char *name, H5L_ff_info_t *linfo /*out*/,
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* Get the link info through the VOL */
     if((ret_value = H5VL_link_get(obj, loc_params, vol_plugin, H5VL_LINK_GET_INFO, 
-                                  H5AC_dxpl_id, eq_id, linfo)) < 0)
+                                  dxpl_id, eq_id, linfo)) < 0)
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get group info")
 
 done:
@@ -2359,6 +2523,8 @@ H5Lget_val_ff(hid_t loc_id, const char *name, void *buf/*out*/, size_t size,
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -2386,9 +2552,15 @@ H5Lget_val_ff(hid_t loc_id, const char *name, void *buf/*out*/, size_t size,
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* Get the link info through the VOL */
     if((ret_value = H5VL_link_get(obj, loc_params, vol_plugin, H5VL_LINK_GET_VAL, 
-                                  H5AC_dxpl_id, eq_id, buf, size)) < 0)
+                                  dxpl_id, eq_id, buf, size)) < 0)
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get link value")
 
 done:
@@ -2424,6 +2596,8 @@ H5Oopen_ff(hid_t loc_id, const char *name, hid_t lapl_id, hid_t rcxt_id, hid_t e
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5I_type_t  opened_type;
     void       *opened_obj = NULL;
     H5VL_loc_params_t loc_params;
@@ -2447,9 +2621,15 @@ H5Oopen_ff(hid_t loc_id, const char *name, hid_t lapl_id, hid_t rcxt_id, hid_t e
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* Open the object through the VOL */
     if(NULL == (opened_obj = H5VL_object_open(obj, loc_params, vol_plugin, &opened_type, 
-                                              H5AC_dxpl_id, eq_id)))
+                                              dxpl_id, eq_id)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to open object")
 
     if ((ret_value = H5VL_object_register(opened_obj, opened_type, vol_plugin, TRUE)) < 0)
@@ -2484,6 +2664,8 @@ H5Oopen_by_addr_ff(hid_t loc_id, haddr_ff_t addr, H5O_type_t type,
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5I_type_t  opened_type;
     void       *opened_obj = NULL;
     H5VL_loc_params_t loc_params;
@@ -2504,16 +2686,22 @@ H5Oopen_by_addr_ff(hid_t loc_id, haddr_ff_t addr, H5O_type_t type,
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     if(H5O_TYPE_NAMED_DATATYPE == type) {
         /* Open the object through the VOL */
         if(NULL == (opened_obj = H5VL_object_open(obj, loc_params, vol_plugin, &opened_type, 
-                                                  H5AC_dxpl_id, H5_EVENT_QUEUE_NULL)))
+                                                  dxpl_id, H5_EVENT_QUEUE_NULL)))
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to open object")
     }
     else {
         /* Open the object through the VOL */
         if(NULL == (opened_obj = H5VL_object_open(obj, loc_params, vol_plugin, &opened_type, 
-                                                  H5AC_dxpl_id, eq_id)))
+                                                  dxpl_id, eq_id)))
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to open object")
     }
     if ((ret_value = H5VL_object_register(opened_obj, opened_type, vol_plugin, TRUE)) < 0)
@@ -2556,6 +2744,7 @@ H5Olink_ff(hid_t obj_id, hid_t new_loc_id, const char *new_name, hid_t lcpl_id,
     H5VL_loc_params_t loc_params1;
     H5VL_loc_params_t loc_params2;
     H5P_genplist_t *plist;      /* Property list pointer */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
     herr_t         ret_value = SUCCEED;       /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -2619,10 +2808,16 @@ H5Olink_ff(hid_t obj_id, hid_t new_loc_id, const char *new_name, hid_t lcpl_id,
     if(H5P_set(plist, H5VL_LINK_TARGET_LOC_PARAMS, &loc_params1) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for target id")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* Create the link through the VOL */
     if((ret_value = H5VL_link_create(H5VL_LINK_CREATE_HARD, obj2, loc_params2, 
                                      (vol_plugin1!=NULL ? vol_plugin1 : vol_plugin2),
-                                     lcpl_id, lapl_id, H5AC_dxpl_id, eq_id)) < 0)
+                                     lcpl_id, lapl_id, dxpl_id, eq_id)) < 0)
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create link")
 
 done:
@@ -2649,6 +2844,8 @@ H5Oexists_by_name_ff(hid_t loc_id, const char *name, htri_t *ret, hid_t lapl_id,
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t  ret_value = SUCCEED;       /* Return value */
 
@@ -2676,9 +2873,15 @@ H5Oexists_by_name_ff(hid_t loc_id, const char *name, htri_t *ret, hid_t lapl_id,
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* change the ref count through the VOL */
     if(H5VL_object_get(obj, loc_params, vol_plugin, H5VL_OBJECT_EXISTS, 
-                       H5AC_dxpl_id, eq_id, ret) < 0)
+                       dxpl_id, eq_id, ret) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to determine if '%s' exists", name)
 
 done:
@@ -2708,6 +2911,8 @@ H5Oset_comment_ff(hid_t obj_id, const char *comment, hid_t trans_id, hid_t eq_id
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -2724,9 +2929,15 @@ H5Oset_comment_ff(hid_t obj_id, const char *comment, hid_t trans_id, hid_t eq_id
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(obj_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* set comment on object through the VOL */
     if(H5VL_object_misc(obj, loc_params, vol_plugin, H5VL_OBJECT_SET_COMMENT, 
-                        H5AC_dxpl_id, eq_id, comment) < 0)
+                        dxpl_id, eq_id, comment) < 0)
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to set comment value")
 
 done:
@@ -2757,6 +2968,8 @@ H5Oset_comment_by_name_ff(hid_t loc_id, const char *name, const char *comment,
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -2784,9 +2997,15 @@ H5Oset_comment_by_name_ff(hid_t loc_id, const char *name, const char *comment,
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* set comment on object through the VOL */
     if(H5VL_object_misc(obj, loc_params, vol_plugin, H5VL_OBJECT_SET_COMMENT, 
-                        H5AC_dxpl_id, eq_id, comment) < 0)
+                        dxpl_id, eq_id, comment) < 0)
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to set comment value")
 
 done:
@@ -2812,6 +3031,8 @@ H5Oget_comment_ff(hid_t loc_id, char *comment, size_t bufsize, ssize_t *ret,
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t ret_value = SUCCEED;              /* Return value */
 
@@ -2828,8 +3049,14 @@ H5Oget_comment_ff(hid_t loc_id, char *comment, size_t bufsize, ssize_t *ret,
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     if(H5VL_object_get(obj, loc_params, vol_plugin, H5VL_OBJECT_GET_COMMENT, 
-                       H5AC_dxpl_id, eq_id, comment, bufsize, ret) < 0)
+                       dxpl_id, eq_id, comment, bufsize, ret) < 0)
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get object comment")
 
 done:
@@ -2855,6 +3082,8 @@ H5Oget_comment_by_name_ff(hid_t loc_id, const char *name, char *comment, size_t
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t ret_value = SUCCEED;              /* Return value */
 
@@ -2883,8 +3112,14 @@ H5Oget_comment_by_name_ff(hid_t loc_id, const char *name, char *comment, size_t
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     if(H5VL_object_get(obj, loc_params, vol_plugin, H5VL_OBJECT_GET_COMMENT, 
-                       H5AC_dxpl_id, eq_id, comment, bufsize, ret) < 0)
+                       dxpl_id, eq_id, comment, bufsize, ret) < 0)
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get object info")
 
 done:
@@ -2919,6 +3154,8 @@ H5Ocopy_ff(hid_t src_loc_id, const char *src_name, hid_t dst_loc_id,
     void    *obj2 = NULL;        /* object token of dst_id */
     H5VL_t  *vol_plugin2;        /* VOL plugin information */
     H5VL_loc_params_t loc_params2;
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist;      /* Property list pointer */
     herr_t      ret_value = SUCCEED;        /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -2957,10 +3194,16 @@ H5Ocopy_ff(hid_t src_loc_id, const char *src_name, hid_t dst_loc_id,
     loc_params2.type = H5VL_OBJECT_BY_SELF;
     loc_params2.obj_type = H5I_get_type(dst_loc_id);
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* Open the object through the VOL */
     if((ret_value = H5VL_object_copy(obj1, loc_params1, vol_plugin1, src_name, 
                                      obj2, loc_params2, vol_plugin2, dst_name, 
-                                     ocpypl_id, lcpl_id, H5AC_dxpl_id, eq_id)) < 0)
+                                     ocpypl_id, lcpl_id, dxpl_id, eq_id)) < 0)
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to open object")
 done:
     FUNC_LEAVE_API(ret_value)
@@ -2985,6 +3228,8 @@ H5Oget_info_ff(hid_t loc_id, H5O_ff_info_t *oinfo, hid_t rcxt_id, hid_t eq_id)
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -3005,9 +3250,15 @@ H5Oget_info_ff(hid_t loc_id, H5O_ff_info_t *oinfo, hid_t rcxt_id, hid_t eq_id)
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* Get the group info through the VOL using the location token */
     if((ret_value = H5VL_object_get(obj, loc_params, vol_plugin, H5VL_OBJECT_GET_INFO, 
-                                    H5AC_dxpl_id, eq_id, oinfo)) < 0)
+                                    dxpl_id, eq_id, oinfo)) < 0)
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get group info")
 
 done:
@@ -3034,6 +3285,8 @@ H5Oget_info_by_name_ff(hid_t loc_id, const char *name, H5O_ff_info_t *oinfo,
 {
     void    *obj = NULL;        /* object token of loc_id */
     H5VL_t  *vol_plugin;        /* VOL plugin information */
+    hid_t dxpl_id = H5P_DATASET_XFER_DEFAULT; /* transfer property list to pass to the VOL plugin */
+    H5P_genplist_t *plist ;     /* Property list pointer */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -3059,14 +3312,19 @@ H5Oget_info_by_name_ff(hid_t loc_id, const char *name, H5O_ff_info_t *oinfo,
     /* get the file object */
     if(NULL == (obj = (void *)H5VL_get_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
-
     /* get the plugin pointer */
     if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information")
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* Get the group info through the VOL using the location token */
     if((ret_value = H5VL_object_get(obj, loc_params, vol_plugin, H5VL_OBJECT_GET_INFO, 
-                                    H5AC_dxpl_id, eq_id, oinfo)) < 0)
+                                    dxpl_id, eq_id, oinfo)) < 0)
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get group info")
 
 done:
@@ -3436,6 +3694,7 @@ herr_t H5DOappend_ff(hid_t dset_id, hid_t dxpl_id, unsigned axis, size_t extensi
     hid_t    new_space_id = FAIL; /* new file space (after extension) */
     hid_t    mem_space_id = FAIL; /* memory space for data buffer */
     hsize_t nelmts; /* number of elements in selection */
+    H5P_genplist_t *plist;      /* Property list pointer */
     herr_t   ret_value = SUCCEED;
 
     FUNC_ENTER_API(FAIL)
@@ -3451,6 +3710,12 @@ herr_t H5DOappend_ff(hid_t dset_id, hid_t dxpl_id, unsigned axis, size_t extensi
         if(TRUE != H5P_isa_class(dxpl_id, H5P_DATASET_XFER))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not xfer parms");
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the dataspace of the dataset */
     if(FAIL == (space_id = H5Dget_space(dset_id)))
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get dataspace");
@@ -3533,6 +3798,7 @@ H5DOsequence_ff(hid_t dset_id, hid_t dxpl_id, unsigned axis, hsize_t start_off,
     hid_t    space_id = FAIL; /* old File space */
     hid_t    mem_space_id = FAIL; /* memory space for data buffer */
     hsize_t nelmts; /* number of elements in selection */
+    H5P_genplist_t *plist;      /* Property list pointer */
     herr_t   ret_value = SUCCEED;
 
     FUNC_ENTER_API(FAIL)
@@ -3550,6 +3816,12 @@ H5DOsequence_ff(hid_t dset_id, hid_t dxpl_id, unsigned axis, hsize_t start_off,
         if(TRUE != H5P_isa_class(dxpl_id, H5P_DATASET_XFER))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not xfer parms");
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* get the dataspace of the dataset */
     if(FAIL == (space_id = H5Dget_space(dset_id)))
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get dataspace");
@@ -3606,6 +3878,7 @@ herr_t H5DOset_ff(hid_t dset_id, hid_t dxpl_id, const hsize_t coord[],
     hid_t    space_id = FAIL; /* old File space */
     hid_t    mem_space_id = FAIL; /* memory space for data buffer */
     hsize_t  nelmts = 1;
+    H5P_genplist_t *plist;      /* Property list pointer */
     herr_t   ret_value = SUCCEED;
 
     FUNC_ENTER_API(FAIL)
@@ -3621,6 +3894,12 @@ herr_t H5DOset_ff(hid_t dset_id, hid_t dxpl_id, const hsize_t coord[],
         if(TRUE != H5P_isa_class(dxpl_id, H5P_DATASET_XFER))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not xfer parms");
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id")
+
     /* get the dataspace of the dataset */
     if(FAIL == (space_id = H5Dget_space(dset_id)))
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get dataspace");
@@ -3653,6 +3932,7 @@ herr_t H5DOget_ff(hid_t dset_id, hid_t dxpl_id, const hsize_t coord[],
     hid_t    space_id = FAIL; /* old File space */
     hid_t    mem_space_id = FAIL; /* memory space for data buffer */
     hsize_t  nelmts = 1;
+    H5P_genplist_t *plist;      /* Property list pointer */
     herr_t   ret_value = SUCCEED;
 
     FUNC_ENTER_API(FAIL)
@@ -3668,6 +3948,12 @@ herr_t H5DOget_ff(hid_t dset_id, hid_t dxpl_id, const hsize_t coord[],
         if(TRUE != H5P_isa_class(dxpl_id, H5P_DATASET_XFER))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not xfer parms");
 
+    /* store the transaction ID in the dxpl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+    if(H5P_set(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for rcxt_id")
+
     /* get the dataspace of the dataset */
     if(FAIL == (space_id = H5Dget_space(dset_id)))
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTGET, FAIL, "unable to get dataspace");
diff --git a/src/H5FFprivate.h b/src/H5FFprivate.h
index 132ff28..1aad9cf 100644
--- a/src/H5FFprivate.h
+++ b/src/H5FFprivate.h
@@ -28,7 +28,8 @@
 /**************************/
 /* Library Private Macros */
 /**************************/
-
+#define H5VL_TRANS_ID        "transaction_id"
+#define H5VL_CONTEXT_ID      "read_context_id"
 
 /****************************/
 /* Library Private Typedefs */
diff --git a/src/H5FFpublic.h b/src/H5FFpublic.h
index 8e06882..d80bad3 100644
--- a/src/H5FFpublic.h
+++ b/src/H5FFpublic.h
@@ -69,7 +69,6 @@ H5_DLL hid_t H5Fcreate_ff(const char *filename, unsigned flags, hid_t fcpl,
                           hid_t fapl, hid_t eq_id);
 H5_DLL hid_t H5Fopen_ff(const char *filename, unsigned flags, hid_t fapl_id,
                         hid_t eq_id);
-H5_DLL herr_t H5Fflush_ff(hid_t object_id, H5F_scope_t scope, hid_t eq_id);
 H5_DLL herr_t H5Fclose_ff(hid_t file_id, hid_t eq_id);
 
 H5_DLL hid_t H5Gcreate_ff(hid_t loc_id, const char *name, hid_t lcpl_id,
diff --git a/src/H5M.c b/src/H5M.c
index 025ea9c..d21c32c 100644
--- a/src/H5M.c
+++ b/src/H5M.c
@@ -361,7 +361,13 @@ H5Mopen_ff(hid_t loc_id, const char *name, hid_t mapl_id, hid_t rcxt_id, hid_t e
     /* increment the ref count on the VOL plugin */
     vol_plugin->nrefs ++;
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue")
     }
 
@@ -445,7 +451,13 @@ H5Mset_ff(hid_t map_id, hid_t key_mem_type_id, const void *key, hid_t val_mem_ty
 	HGOTO_ERROR(H5E_SYM, H5E_CANTSET, FAIL, "can't set map KV pair")
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -522,7 +534,13 @@ H5Mget_ff(hid_t map_id, hid_t key_mem_type_id, const void *key, hid_t val_mem_ty
 	HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get map value")
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -591,7 +609,13 @@ H5Mget_types_ff(hid_t map_id, hid_t *key_type_id, hid_t *val_type_id,
 	HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get map value")
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -655,7 +679,13 @@ H5Mget_count_ff(hid_t map_id, hsize_t *count, hid_t rcxt_id, hid_t eq_id)
 	HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get map value")
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -722,7 +752,13 @@ H5Mexists_ff(hid_t map_id, hid_t key_mem_type_id, const void *key,
 	HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get map value")
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -832,7 +868,13 @@ H5Mdelete_ff(hid_t map_id, hid_t key_mem_type_id, const void *key,
 	HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get map value")
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 done:
diff --git a/src/H5Pdxpl.c b/src/H5Pdxpl.c
index 7ece9c6..d02ec73 100644
--- a/src/H5Pdxpl.c
+++ b/src/H5Pdxpl.c
@@ -37,6 +37,7 @@
 #include "H5ACprivate.h"    /* Cache */
 #include "H5Dprivate.h"		/* Datasets				*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5FFprivate.h"	/* Fast Forward routines	  	*/
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5MMprivate.h"	/* Memory management			*/
 #include "H5Ppkg.h"		/* Property lists		  	*/
@@ -308,6 +309,8 @@ static const size_t H5D_def_direct_chunk_datasize_g = H5D_XFER_DIRECT_CHUNK_WRIT
 static herr_t
 H5P__dxfr_reg_prop(H5P_genclass_t *pclass)
 {
+    hid_t trans_id = FAIL;
+    hid_t context_id = FAIL;
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_STATIC
@@ -508,6 +511,16 @@ H5P__dxfr_reg_prop(H5P_genclass_t *pclass)
             NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
+    /* Register the transaction ID property*/
+    if(H5P_register_real(pclass, H5VL_TRANS_ID, sizeof(hid_t), &trans_id, 
+                         NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
+    /* Register the context ID property*/
+    if(H5P_register_real(pclass, H5VL_CONTEXT_ID, sizeof(hid_t), &context_id, 
+                         NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5P__dxfr_reg_prop() */
diff --git a/src/H5RC.c b/src/H5RC.c
index aecf4f7..61cd0c2 100644
--- a/src/H5RC.c
+++ b/src/H5RC.c
@@ -325,11 +325,16 @@ H5RC_create(void *file, uint64_t c_version)
 
     /* allocate read context struct */
     if(NULL == (rc = H5FL_CALLOC(H5RC_t)))
-	HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate top read context structure")
+	HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate read context structure")
 
     rc->file = (H5VL_iod_file_t *)file;
     rc->c_version = c_version;
 
+    rc->req_info.request = NULL;
+    rc->req_info.head = NULL;
+    rc->req_info.tail = NULL;
+    rc->req_info.num_req = 0;
+
     /* set return value */
     ret_value = rc;
 
@@ -407,8 +412,14 @@ H5RCacquire(hid_t file_id, /*IN/OUT*/ uint64_t *c_version,
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to request a read context on container");
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
-            HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
+            HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue")
     }
 
 done:
@@ -447,7 +458,7 @@ H5RCrelease(hid_t rc_id , hid_t eq_id)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Read Context ID")
 
     /* get the plugin pointer */
-    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(eq_id)))
+    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(rc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information");
 
     if(eq_id != H5_EVENT_QUEUE_NULL) {
@@ -464,7 +475,13 @@ H5RCrelease(hid_t rc_id , hid_t eq_id)
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to request a release on a read context on container");
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -503,7 +520,7 @@ H5RCpersist(hid_t rc_id , hid_t eq_id)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Read Context ID")
 
     /* get the plugin pointer */
-    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(eq_id)))
+    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(rc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information");
 
     if(eq_id != H5_EVENT_QUEUE_NULL) {
@@ -520,7 +537,13 @@ H5RCpersist(hid_t rc_id , hid_t eq_id)
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to request a persist on a read context on container");
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -563,7 +586,7 @@ H5RCsnapshot(hid_t rc_id , const char *snapshot_name, hid_t eq_id)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Read Context ID")
 
     /* get the plugin pointer */
-    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(eq_id)))
+    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(rc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information");
 
     if(eq_id != H5_EVENT_QUEUE_NULL) {
@@ -580,7 +603,13 @@ H5RCsnapshot(hid_t rc_id , const char *snapshot_name, hid_t eq_id)
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to request a snapshot on a read context on container");
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -640,6 +669,49 @@ H5RC_close(H5RC_t *rc)
 {
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
+    if(rc->req_info.num_req) {
+        H5VL_iod_request_t *cur_req = rc->req_info.head;
+        H5VL_iod_request_t *next_req = NULL;
+        H5VL_iod_request_t *prev;
+        H5VL_iod_request_t *next;
+
+        while(cur_req) {
+            next_req = cur_req->trans_next;
+
+            /* remove the current request from the linked list */
+            prev = cur_req->trans_prev;
+            next = cur_req->trans_next;
+            if (prev) {
+                if (next) {
+                    prev->trans_next = next;
+                    next->trans_prev = prev;
+                }
+                else {
+                    prev->trans_next = NULL;
+                    rc->req_info.tail = prev;
+                }
+            }
+            else {
+                if (next) {
+                    next->trans_prev = NULL;
+                    rc->req_info.head = next;
+                }
+                else {
+                    rc->req_info.head = NULL;
+                    rc->req_info.tail = NULL;
+                }
+            }
+
+            cur_req->trans_prev = NULL;
+            cur_req->trans_next = NULL;
+
+            rc->req_info.num_req --;
+
+            cur_req = next_req;
+        }
+        HDassert(0 == rc->req_info.num_req);
+    }
+
     rc = H5FL_FREE(H5RC_t, rc);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
diff --git a/src/H5RCprivate.h b/src/H5RCprivate.h
index bb77ede..a280ff9 100644
--- a/src/H5RCprivate.h
+++ b/src/H5RCprivate.h
@@ -36,8 +36,19 @@
 /****************************/
 /* Library Private Typedefs */
 /****************************/
+
+/* Request and Linked list info used in transactions and read contexts
+   to track dependencies. */
+typedef struct H5VL_iod_req_info_t {
+    struct H5VL_iod_request_t *request;
+    struct H5VL_iod_request_t *head;
+    struct H5VL_iod_request_t *tail;
+    size_t num_req;
+} H5VL_iod_req_info_t;
+
 /* the client Read Context struct */
 typedef struct H5RC_t {
+    H5VL_iod_req_info_t req_info; /* must be first */
     struct H5VL_iod_file_t *file;
     uint64_t c_version;
 } H5RC_t;
diff --git a/src/H5RCpublic.h b/src/H5RCpublic.h
index 4d6b500..290fe2c 100644
--- a/src/H5RCpublic.h
+++ b/src/H5RCpublic.h
@@ -37,6 +37,7 @@
 /*******************/
 typedef enum H5RC_request_t{
     H5RC_EXACT, /* default */
+    H5RC_PREV,
     H5RC_NEXT,
     H5RC_LAST
 } H5RC_request_t;
diff --git a/src/H5TR.c b/src/H5TR.c
index 191c379..a929cd0 100644
--- a/src/H5TR.c
+++ b/src/H5TR.c
@@ -349,6 +349,11 @@ H5TR_create(void *file, H5RC_t *rc, uint64_t trans_num)
     tr->c_version = rc->c_version;
     tr->trans_num = trans_num;
 
+    tr->req_info.request = NULL;
+    tr->req_info.head = NULL;
+    tr->req_info.tail = NULL;
+    tr->req_info.num_req = 0;
+
     /* set return value */
     ret_value = tr;
 
@@ -396,7 +401,7 @@ H5TRstart(hid_t tr_id, hid_t trspl_id, hid_t eq_id)
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not transaction start property list")
 
     /* get the plugin pointer */
-    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(eq_id)))
+    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(tr_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information");
 
     if(eq_id != H5_EVENT_QUEUE_NULL) {
@@ -413,7 +418,13 @@ H5TRstart(hid_t tr_id, hid_t trspl_id, hid_t eq_id)
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to request a transaction start");
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -466,7 +477,7 @@ H5TRfinish(hid_t tr_id, hid_t trfpl_id, hid_t *rcxt_id, hid_t eq_id)
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not transaction finish property list")
 
     /* get the plugin pointer */
-    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(eq_id)))
+    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(tr_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information");
 
     /* create a new read context object (if user requested it) with
@@ -495,7 +506,13 @@ H5TRfinish(hid_t tr_id, hid_t trfpl_id, hid_t *rcxt_id, hid_t eq_id)
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to request a transaction finish");
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -539,7 +556,7 @@ H5TRset_dependency(hid_t tr_id, uint64_t trans_num, hid_t eq_id)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "The dependent transaction must be higher than the one it depends on")
 
     /* get the plugin pointer */
-    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(eq_id)))
+    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(tr_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information");
 
     if(eq_id != H5_EVENT_QUEUE_NULL) {
@@ -556,7 +573,13 @@ H5TRset_dependency(hid_t tr_id, uint64_t trans_num, hid_t eq_id)
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to request a transaction set_dependency");
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -611,7 +634,13 @@ H5TRskip(hid_t file_id, uint64_t start_trans_num, uint64_t count, hid_t eq_id)
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to request a transaction skip");
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -646,7 +675,7 @@ H5TRabort(hid_t tr_id, hid_t eq_id)
     H5TRACE2("e", "ii", tr_id, eq_id);
 
     /* get the plugin pointer */
-    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(eq_id)))
+    if (NULL == (vol_plugin = (H5VL_t *)H5I_get_aux(tr_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID does not contain VOL information");
 
     /* get the TR object */
@@ -667,7 +696,13 @@ H5TRabort(hid_t tr_id, hid_t eq_id)
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to request a transaction abort");
 
     if(request && *req) {
-        if(H5EQinsert(eq_id, request) < 0)
+        H5EQ_t *eq = NULL;                    /* event queue token */
+
+        /* get the eq object */
+        if(NULL == (eq = (H5EQ_t *)H5I_object_verify(eq_id, H5I_EQ)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event queue identifier")
+
+        if(H5EQ_insert(eq, request) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "failed to insert request in event queue");
     }
 
@@ -724,8 +759,52 @@ done:
 herr_t
 H5TR_close(H5TR_t *tr)
 {
+
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
+    if(tr->req_info.num_req) {
+        H5VL_iod_request_t *cur_req = tr->req_info.head;
+        H5VL_iod_request_t *next_req = NULL;
+        H5VL_iod_request_t *prev;
+        H5VL_iod_request_t *next;
+
+        while(cur_req) {
+            next_req = cur_req->trans_next;
+
+            /* remove the current request from the linked list */
+            prev = cur_req->trans_prev;
+            next = cur_req->trans_next;
+            if (prev) {
+                if (next) {
+                    prev->trans_next = next;
+                    next->trans_prev = prev;
+                }
+                else {
+                    prev->trans_next = NULL;
+                    tr->req_info.tail = prev;
+                }
+            }
+            else {
+                if (next) {
+                    next->trans_prev = NULL;
+                    tr->req_info.head = next;
+                }
+                else {
+                    tr->req_info.head = NULL;
+                    tr->req_info.tail = NULL;
+                }
+            }
+
+            cur_req->trans_prev = NULL;
+            cur_req->trans_next = NULL;
+
+            tr->req_info.num_req --;
+
+            cur_req = next_req;
+        }
+        HDassert(0 == tr->req_info.num_req);
+    }
+
     tr = H5FL_FREE(H5TR_t, tr);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
diff --git a/src/H5TRprivate.h b/src/H5TRprivate.h
index d648d2b..4c20073 100644
--- a/src/H5TRprivate.h
+++ b/src/H5TRprivate.h
@@ -34,12 +34,13 @@
 /****************************/
 /* Library Private Typedefs */
 /****************************/
+
 /* the transaction struct */
 typedef struct H5TR_t {
+    H5VL_iod_req_info_t req_info; /* must be first */
     struct H5VL_iod_file_t *file;
     uint64_t c_version;
     uint64_t trans_num;
-    struct H5VL_iod_request_t *request;
 } H5TR_t;
 
 /*****************************/
diff --git a/src/H5VLiod.c b/src/H5VLiod.c
index 771d4ff..a1d8ac4 100644
--- a/src/H5VLiod.c
+++ b/src/H5VLiod.c
@@ -27,6 +27,7 @@
 #include "H5private.h"		/* Generic Functions			*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5FDprivate.h"        /* file drivers            		*/
+#include "H5FFprivate.h"        /* Fast Forward            		*/
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5MMprivate.h"	/* Memory management			*/
 #include "H5Pprivate.h"		/* Property lists			*/
@@ -42,7 +43,6 @@ static hg_id_t H5VL_EFF_INIT_ID;
 static hg_id_t H5VL_EFF_FINALIZE_ID;
 static hg_id_t H5VL_FILE_CREATE_ID;
 static hg_id_t H5VL_FILE_OPEN_ID;
-static hg_id_t H5VL_FILE_FLUSH_ID;
 static hg_id_t H5VL_FILE_CLOSE_ID;
 static hg_id_t H5VL_ATTR_CREATE_ID;
 static hg_id_t H5VL_ATTR_OPEN_ID;
@@ -149,9 +149,7 @@ static herr_t H5VL_iod_dataset_close(void *dset, hid_t dxpl_id, void **req);
 /* File callbacks */
 static void *H5VL_iod_file_create(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id, hid_t dxpl_id, void **req);
 static void *H5VL_iod_file_open(const char *name, unsigned flags, hid_t fapl_id, hid_t dxpl_id, void **req);
-static herr_t H5VL_iod_file_flush(void *obj, H5VL_loc_params_t loc_params, H5F_scope_t scope, hid_t dxpl_id, void **req);
 static herr_t H5VL_iod_file_get(void *file, H5VL_file_get_t get_type, hid_t dxpl_id, void **req, va_list arguments);
-static herr_t H5VL_iod_file_misc(void *file, H5VL_file_misc_t misc_type, hid_t dxpl_id, void **req, va_list arguments);
 static herr_t H5VL_iod_file_close(void *file, hid_t dxpl_id, void **req);
 
 /* Group callbacks */
@@ -236,9 +234,9 @@ static H5VL_class_t H5VL_iod_g = {
     {                                           /* file_cls */
         H5VL_iod_file_create,                   /* create */
         H5VL_iod_file_open,                     /* open */
-        H5VL_iod_file_flush,                    /* flush */
+        NULL,                                   /* flush */
         H5VL_iod_file_get,                      /* get */
-        H5VL_iod_file_misc,                     /* misc */
+        NULL,                                   /* misc */
         NULL,                                   /* optional */
         H5VL_iod_file_close                     /* close */
     },
@@ -419,9 +417,13 @@ H5VL__iod_request_add_to_axe_list(H5VL_iod_request_t *request)
 
     /* process axe_list */
     while(axe_list.head && /* If there is a head request */
+          /* and the only reference is from this global axe list OR
+             from the axe list and the file list */
           (axe_list.head->ref_count == 1 || (axe_list.head->ref_count == 2 && request->req != NULL)) &&
+          /* and the request has completed */
           H5VL_IOD_COMPLETED == axe_list.head->state) {
 
+        /* add the axe IDs to the ones to free. */
         axe_list.last_released_task = axe_list.head->axe_id;
 
         /* remove head from axe list */
@@ -450,12 +452,15 @@ herr_t
 H5VL__iod_create_and_forward(hg_id_t op_id, H5RQ_type_t op_type, 
                              H5VL_iod_object_t *request_obj, htri_t track,
                              size_t num_parents, H5VL_iod_request_t **parent_reqs,
+                             H5VL_iod_req_info_t *req_info,
                              void *input, void *output, void *data, void **req)
 {
     hg_request_t *hg_req = NULL;
     H5VL_iod_request_t *request = NULL;
     hbool_t do_async = (req == NULL) ? FALSE : TRUE;  /* Whether we're performing async. I/O */
     axe_t *axe_info = (axe_t *) input;
+    AXE_task_t *parent_axe_ids = NULL;
+    unsigned u;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -468,6 +473,9 @@ H5VL__iod_create_and_forward(hg_id_t op_id, H5RQ_type_t op_type,
     if(NULL == (request = (H5VL_iod_request_t *)H5MM_malloc(sizeof(H5VL_iod_request_t))))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate IOD VOL request struct");
 
+    /* get axe ID for operation */
+    axe_info->axe_id = g_axe_id ++;
+
     /* Set up request */
     HDmemset(request, 0, sizeof(*request));
     request->type = op_type;
@@ -476,8 +484,9 @@ H5VL__iod_create_and_forward(hg_id_t op_id, H5RQ_type_t op_type,
     request->ref_count = 1;
     request->obj = request_obj;
     request->axe_id = axe_info->axe_id;
-    request->next = request->prev = NULL;
+    request->file_next = request->file_prev = NULL;
     request->global_next = request->global_prev = NULL;
+    request->trans_info = req_info;
 
     /* add request to container's linked list */
     H5VL_iod_request_add(request_obj->file, request);
@@ -486,15 +495,32 @@ H5VL__iod_create_and_forward(hg_id_t op_id, H5RQ_type_t op_type,
     request->num_parents = num_parents;
     request->parent_reqs = parent_reqs;
 
+    if(num_parents) {
+        if(NULL == (parent_axe_ids = (AXE_task_t *)H5MM_malloc(sizeof(AXE_task_t) * num_parents)))
+            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent axe IDs");
+
+        for(u=0 ; u<num_parents ; u++)
+            parent_axe_ids[u] = parent_reqs[u]->axe_id;
+    }
+
+    axe_info->num_parents = num_parents;
+    axe_info->parent_axe_ids = parent_axe_ids;
+
     axe_info->start_range = axe_list.last_released_task + 1;
     /* add request to global axe's linked list */
     H5VL__iod_request_add_to_axe_list(request);
     axe_info->count = axe_list.last_released_task - axe_info->start_range + 1;
 
 #if H5VL_IOD_DEBUG
+    printf("Operation %llu Dependencies: ", request->axe_id);
+    for(u=0 ; u<num_parents ; u++)
+        printf("%llu ", axe_info->parent_axe_ids[u]);
+    printf("\n");
+
     if(axe_info->count) {
         printf("Operation %llu will finish tasks %llu through %llu\n",
-                request->axe_id, axe_info->start_range, axe_info->start_range+axe_info->count-1);
+               request->axe_id, axe_info->start_range, 
+               axe_info->start_range+axe_info->count-1);
     }
 #endif
 
@@ -525,6 +551,7 @@ H5VL__iod_create_and_forward(hg_id_t op_id, H5RQ_type_t op_type,
     } /* end else */
 
 done:
+    parent_axe_ids = (AXE_task_t *)H5MM_xfree(parent_axe_ids);
     FUNC_LEAVE_NOAPI(ret_value)
 }/* end H5VL__iod_create_and_forward() */
 
@@ -591,7 +618,6 @@ EFF_init(MPI_Comm comm, MPI_Info UNUSED info)
 
     H5VL_FILE_CREATE_ID = MERCURY_REGISTER("file_create", file_create_in_t, file_create_out_t);
     H5VL_FILE_OPEN_ID   = MERCURY_REGISTER("file_open", file_open_in_t, file_open_out_t);
-    H5VL_FILE_FLUSH_ID  = MERCURY_REGISTER("file_flush", file_flush_in_t, ret_t);
     H5VL_FILE_CLOSE_ID  = MERCURY_REGISTER("file_close", file_close_in_t, ret_t);
 
     H5VL_ATTR_CREATE_ID = MERCURY_REGISTER("attr_create", attr_create_in_t, attr_create_out_t);
@@ -691,6 +717,26 @@ EFF_finalize(void)
     hg_request_t hg_req;
     herr_t ret_value = SUCCEED;
 
+    H5VL_iod_request_t *cur_req = axe_list.head;
+
+    /* process axe_list */
+    while(cur_req) {
+        H5VL_iod_request_t *next_req = NULL;
+
+        next_req = cur_req->global_next;
+
+        HDassert(cur_req->ref_count == 1);
+        HDassert(H5VL_IOD_COMPLETED == cur_req->state);
+
+        /* add the axe IDs to the ones to free. */
+        axe_list.last_released_task = cur_req->axe_id;
+
+        /* remove head from axe list */
+        H5VL__iod_request_remove_from_axe_list(cur_req);
+
+        cur_req = next_req;
+    }
+
     /* forward the finalize call to the ION and wait for it to complete */
     if(HG_Forward(PEER, H5VL_EFF_FINALIZE_ID, &ret_value, &ret_value, &hg_req) < 0)
         return FAIL;
@@ -963,7 +1009,7 @@ done:
 herr_t
 H5Pget_dxpl_checksum_ptr(hid_t dxpl_id, uint32_t **cs/*out*/)
 {
-    H5P_genplist_t *plist;              /* Property list pointer */
+    H5P_genplist_t *plist = NULL;              /* Property list pointer */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -998,7 +1044,7 @@ done:
 herr_t
 H5Pset_dxpl_inject_corruption(hid_t dxpl_id, hbool_t flag)
 {
-    H5P_genplist_t *plist;      /* Property list pointer */
+    H5P_genplist_t *plist = NULL;      /* Property list pointer */
     herr_t ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1036,7 +1082,7 @@ done:
 herr_t
 H5Pget_dxpl_inject_corruption(hid_t dxpl_id, hbool_t *flag/*out*/)
 {
-    H5P_genplist_t *plist;              /* Property list pointer */
+    H5P_genplist_t *plist = NULL;              /* Property list pointer */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1072,7 +1118,7 @@ done:
 herr_t
 H5Pset_dcpl_append_only(hid_t dcpl_id, hbool_t flag)
 {
-    H5P_genplist_t *plist;      /* Property list pointer */
+    H5P_genplist_t *plist = NULL;      /* Property list pointer */
     herr_t ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1111,7 +1157,7 @@ done:
 herr_t
 H5Pget_dcpl_append_only(hid_t dcpl_id, hbool_t *flag/*out*/)
 {
-    H5P_genplist_t *plist;              /* Property list pointer */
+    H5P_genplist_t *plist = NULL;              /* Property list pointer */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
@@ -1145,10 +1191,10 @@ done:
  */
 static void *
 H5VL_iod_file_create(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id, 
-                     hid_t dxpl_id, void **req)
+                     hid_t UNUSED dxpl_id, void **req)
 {
     H5VL_iod_fapl_t *fa = NULL;
-    H5P_genplist_t *plist;      /* Property list pointer */
+    H5P_genplist_t *plist = NULL;      /* Property list pointer */
     H5VL_iod_file_t *file = NULL;
     file_create_in_t input;
     void  *ret_value = NULL;
@@ -1187,14 +1233,6 @@ H5VL_iod_file_create(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl
     input.flags = flags;
     input.fcpl_id = fcpl_id;
     input.fapl_id = fapl_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = 0;
-    input.axe_info.parent_axe_ids = NULL;
-
-#if H5VL_IOD_DEBUG
-    printf("File Create %s IOD ROOT ID %llu, axe id %llu\n", 
-           name, input.root_id, input.axe_info.axe_id);
-#endif
 
     /* create the file object that is passed to the API layer */
     file->file_name = HDstrdup(name);
@@ -1216,9 +1254,14 @@ H5VL_iod_file_create(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl
     file->common.obj_name[1] = '\0';
     file->common.file = file;
 
+#if H5VL_IOD_DEBUG
+    printf("File Create %s IOD ROOT ID %llu, axe id %llu\n", 
+           name, input.root_id, g_axe_id);
+#endif
+
     if(H5VL__iod_create_and_forward(H5VL_FILE_CREATE_ID, HG_FILE_CREATE, 
                                     (H5VL_iod_object_t *)file, 1, 0, NULL,
-                                    &input, &file->remote_file, file, req) < 0)
+                                    NULL, &input, &file->remote_file, file, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship file create");
 
     ret_value = (void *)file;
@@ -1242,10 +1285,11 @@ done:
  *-------------------------------------------------------------------------
  */
 static void *
-H5VL_iod_file_open(const char *name, unsigned flags, hid_t fapl_id, hid_t dxpl_id, void **req)
+H5VL_iod_file_open(const char *name, unsigned flags, hid_t fapl_id, 
+                   hid_t UNUSED dxpl_id, void **req)
 {
     H5VL_iod_fapl_t *fa;
-    H5P_genplist_t *plist;      /* Property list pointer */
+    H5P_genplist_t *plist = NULL;      /* Property list pointer */
     H5VL_iod_file_t *file = NULL;
     file_open_in_t input;
     void  *ret_value = NULL;
@@ -1271,13 +1315,6 @@ H5VL_iod_file_open(const char *name, unsigned flags, hid_t fapl_id, hid_t dxpl_i
     input.name = name;
     input.flags = flags;
     input.fapl_id = fapl_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = 0;
-    input.axe_info.parent_axe_ids = NULL;
-
-#if H5VL_IOD_DEBUG
-    printf("File Open %s axe id %llu\n", name, input.axe_info.axe_id);
-#endif
 
     /* create the file object that is passed to the API layer */
     MPI_Comm_rank(fa->comm, &file->my_rank);
@@ -1299,9 +1336,13 @@ H5VL_iod_file_open(const char *name, unsigned flags, hid_t fapl_id, hid_t dxpl_i
     file->common.obj_name[1] = '\0';
     file->common.file = file;
 
+#if H5VL_IOD_DEBUG
+    printf("File Open %s axe id %llu\n", name, g_axe_id);
+#endif
+
     if(H5VL__iod_create_and_forward(H5VL_FILE_OPEN_ID, HG_FILE_OPEN, 
                                     (H5VL_iod_object_t *)file, 1, 0, NULL,
-                                    &input, &file->remote_file, file, req) < 0)
+                                    NULL, &input, &file->remote_file, file, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship file open");
 
     ret_value = (void *)file;
@@ -1312,51 +1353,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5VL_iod_file_flush
- *
- * Purpose:	Flushs a iod HDF5 file.
- *
- * Return:	Success:	0
- *		Failure:	-1, file not flushed.
- *
- * Programmer:  Mohamad Chaarawi
- *              February, 2013
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5VL_iod_file_flush(void *_obj, H5VL_loc_params_t loc_params, H5F_scope_t scope, 
-                    hid_t dxpl_id, void **req)
-{
-    H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj;
-    H5VL_iod_file_t *file = obj->file;
-    int *status;
-    file_flush_in_t input;
-    herr_t ret_value = SUCCEED;       /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    /* set the input structure for the HG encode routine */
-    input.coh = file->remote_file.coh;
-    input.scope = scope;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = 0;
-    input.axe_info.parent_axe_ids = NULL;
-
-    /* allocate an integer to receive the return value if the file close succeeded or not */
-    status = (int *)malloc(sizeof(int));
-
-    if(H5VL__iod_create_and_forward(H5VL_FILE_FLUSH_ID, HG_FILE_FLUSH, 
-                                    (H5VL_iod_object_t *)file, 1, 0, NULL,
-                                    &input, status, status, req) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship file flush");
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5VL_iod_file_flush() */
-
-
-/*-------------------------------------------------------------------------
  * Function:	H5VL_iod_file_get
  *
  * Purpose:	Gets certain data about a file
@@ -1370,7 +1366,8 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5VL_iod_file_get(void *_obj, H5VL_file_get_t get_type, hid_t dxpl_id, void **req, va_list arguments)
+H5VL_iod_file_get(void *_obj, H5VL_file_get_t get_type, hid_t UNUSED dxpl_id, 
+                  void UNUSED **req, va_list arguments)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj;
     H5VL_iod_file_t *file = obj->file;
@@ -1460,25 +1457,17 @@ H5VL_iod_file_get(void *_obj, H5VL_file_get_t get_type, hid_t dxpl_id, void **re
         /* H5Fget_obj_count */
         case H5VL_FILE_GET_OBJ_COUNT:
             {
-                unsigned types = va_arg (arguments, unsigned);
-                ssize_t *ret = va_arg (arguments, ssize_t *);
-                size_t  obj_count = 0;      /* Number of opened objects */
-
-                /* Set the return value */
-                *ret = (ssize_t)obj_count;
+                //unsigned types = va_arg (arguments, unsigned);
+                //ssize_t *ret = va_arg (arguments, ssize_t *);
                 //break;
             }
         /* H5Fget_obj_ids */
         case H5VL_FILE_GET_OBJ_IDS:
             {
-                unsigned types = va_arg (arguments, unsigned);
-                size_t max_objs = va_arg (arguments, size_t);
-                hid_t *oid_list = va_arg (arguments, hid_t *);
-                ssize_t *ret = va_arg (arguments, ssize_t *);
-                size_t  obj_count = 0;      /* Number of opened objects */
-
-                /* Set the return value */
-                *ret = (ssize_t)obj_count;
+                //unsigned types = va_arg (arguments, unsigned);
+                //size_t max_objs = va_arg (arguments, size_t);
+                //hid_t *oid_list = va_arg (arguments, hid_t *);
+                //ssize_t *ret = va_arg (arguments, ssize_t *);
                 //break;
             }
         default:
@@ -1489,6 +1478,7 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_file_get() */
 
+#if 0
 
 /*-------------------------------------------------------------------------
  * Function:	H5VL_iod_file_misc
@@ -1504,7 +1494,8 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5VL_iod_file_misc(void *obj, H5VL_file_misc_t misc_type, hid_t dxpl_id, void **req, va_list arguments)
+H5VL_iod_file_misc(void *obj, H5VL_file_misc_t misc_type, hid_t dxpl_id, 
+                   void **req, va_list arguments)
 {
     herr_t       ret_value = SUCCEED;    /* Return value */
 
@@ -1553,6 +1544,7 @@ H5VL_iod_file_misc(void *obj, H5VL_file_misc_t misc_type, hid_t dxpl_id, void **
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_file_misc() */
+#endif
 
 
 /*-------------------------------------------------------------------------
@@ -1569,7 +1561,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5VL_iod_file_close(void *_file, hid_t dxpl_id, void **req)
+H5VL_iod_file_close(void *_file, hid_t UNUSED dxpl_id, void **req)
 {
     H5VL_iod_file_t *file = (H5VL_iod_file_t *)_file;
     file_close_in_t input;
@@ -1593,15 +1585,6 @@ H5VL_iod_file_close(void *_file, hid_t dxpl_id, void **req)
     input.coh = file->remote_file.coh;
     input.root_oh = file->remote_file.root_oh;
     input.root_id = file->remote_file.root_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    /* MSC - for now, we will insert this as a barrier task so no need
-       to get parent axe IDs */
-    input.axe_info.num_parents = 0;
-    input.axe_info.parent_axe_ids = NULL;
-
-#if H5VL_IOD_DEBUG
-    printf("File Close Root ID %llu axe id %llu\n", input.root_id, input.axe_info.axe_id);
-#endif
 
     if(file->num_req) {
         H5VL_iod_request_t *cur_req = file->request_list_head;
@@ -1616,14 +1599,18 @@ H5VL_iod_file_close(void *_file, hid_t dxpl_id, void **req)
                 cur_req->ref_count ++;
                 num_parents ++;
             }
-            cur_req = cur_req->next;
+            cur_req = cur_req->file_next;
         }
     }
 
+#if H5VL_IOD_DEBUG
+    printf("File Close Root ID %llu axe id %llu\n", input.root_id, g_axe_id);
+#endif
+
     if(H5VL__iod_create_and_forward(H5VL_FILE_CLOSE_ID, HG_FILE_CLOSE, 
                                     (H5VL_iod_object_t *)file, 1,
                                     num_parents, parent_reqs,
-                                    &input, status, status, req) < 0)
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship file close");
 
 done:
@@ -1645,18 +1632,20 @@ done:
  *-------------------------------------------------------------------------
  */
 static void *
-H5VL_iod_group_create(void *_obj, H5VL_loc_params_t loc_params, const char *name, hid_t gcpl_id, 
+H5VL_iod_group_create(void *_obj, H5VL_loc_params_t UNUSED loc_params, const char *name, hid_t gcpl_id, 
                       hid_t gapl_id, hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location object to create the group */
     H5VL_iod_group_t *grp = NULL; /* the group object that is created and passed to the user */
     group_create_in_t input;
-    H5P_genplist_t *plist;
     hid_t lcpl_id;
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    H5VL_iod_request_t **parent_req = NULL;
-    char *new_name = NULL; /* resolved path to where we need to start traversal at the server */
+    H5VL_iod_request_t **parent_reqs = NULL;
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
+    H5P_genplist_t *plist = NULL;
     void *ret_value = NULL;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -1664,18 +1653,32 @@ H5VL_iod_group_create(void *_obj, H5VL_loc_params_t loc_params, const char *name
     /* Get the group creation plist structure */
     if(NULL == (plist = (H5P_genplist_t *)H5I_object(gcpl_id)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, NULL, "can't find object for ID");
-
     /* get creation properties */
     if(H5P_get(plist, H5VL_GRP_LCPL_ID, &lcpl_id) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for lcpl id");
 
-    /* Retrieve the parent AXE id by traversing the path where the
-       group should be created. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, name, &iod_id, &iod_oh, 
-                                parent_req, &new_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current working group");
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, NULL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a Transaction ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current location group info");
 
     /* allocate the group object that is returned to the user */
     if(NULL == (grp = H5FL_CALLOC(H5VL_iod_group_t)))
@@ -1698,24 +1701,12 @@ H5VL_iod_group_create(void *_obj, H5VL_loc_params_t loc_params, const char *name
     input.coh = obj->file->remote_file.coh;
     input.loc_id = iod_id;
     input.loc_oh = iod_oh;
-    input.name = new_name;
+    input.name = name;
     input.gcpl_id = gcpl_id;
     input.gapl_id = gapl_id;
     input.lcpl_id = lcpl_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
-
-#if H5VL_IOD_DEBUG
-    printf("Group Create %s, IOD ID %llu, axe id %llu, parent %llu\n", 
-           new_name, input.grp_id, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
-#endif
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
     /* setup the local group struct */
     /* store the entire path of the group locally */
@@ -1740,17 +1731,20 @@ H5VL_iod_group_create(void *_obj, H5VL_loc_params_t loc_params, const char *name
     grp->common.file = obj->file;
     grp->common.file->nopen_objs ++;
 
+#if H5VL_IOD_DEBUG
+    printf("Group Create %s, IOD ID %llu, axe id %llu\n", 
+           name, input.grp_id, g_axe_id);
+#endif
+
     if(H5VL__iod_create_and_forward(H5VL_GROUP_CREATE_ID, HG_GROUP_CREATE, 
                                     (H5VL_iod_object_t *)grp, 1, 
-                                    input.axe_info.num_parents, parent_req,
+                                    num_parents, parent_reqs, (H5VL_iod_req_info_t *)tr,
                                     &input, &grp->remote_group, grp, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship group create");
 
     ret_value = (void *)grp;
 
 done:
-    if(new_name) 
-        free(new_name);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_group_create() */
 
@@ -1769,27 +1763,45 @@ done:
  *-------------------------------------------------------------------------
  */
 static void *
-H5VL_iod_group_open(void *_obj, H5VL_loc_params_t loc_params, const char *name, 
+H5VL_iod_group_open(void *_obj, H5VL_loc_params_t UNUSED loc_params, const char *name, 
                     hid_t gapl_id, hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location object to create the group */
     H5VL_iod_group_t  *grp = NULL; /* the group object that is created and passed to the user */
+    group_open_in_t input;
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    H5VL_iod_request_t **parent_req = NULL;
-    char *new_name = NULL; /* resolved path to where we need to start traversal at the server */
-    group_open_in_t input;
+    H5P_genplist_t *plist = NULL;
+    hid_t rcxt_id;
+    H5RC_t *rc;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     void *ret_value = NULL;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    /* Retrieve the parent AXE id by traversing the path where the
-       group should be opened. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, name, &iod_id, &iod_oh, 
-                                parent_req, &new_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current working group");
+    /* get the context ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, NULL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for trans_id");
+
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a READ CONTEXT ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)rc, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current location group info");
 
     /* allocate the group object that is returned to the user */
     if(NULL == (grp = H5FL_CALLOC(H5VL_iod_group_t)))
@@ -1802,21 +1814,13 @@ H5VL_iod_group_open(void *_obj, H5VL_loc_params_t loc_params, const char *name,
     input.coh = obj->file->remote_file.coh;
     input.loc_id = iod_id;
     input.loc_oh = iod_oh;
-    input.name = new_name;
+    input.name = name;
     input.gapl_id = gapl_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
+    input.rcxt_num  = rc->c_version;
 
 #if H5VL_IOD_DEBUG
-    printf("Group Open %s LOC ID %llu, axe id %llu, parent %llu\n", 
-           new_name, input.loc_id, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Group Open %s LOC ID %llu, axe id %llu\n", 
+           name, input.loc_id, g_axe_id);
 #endif
 
     /* setup the local group struct */
@@ -1842,15 +1846,13 @@ H5VL_iod_group_open(void *_obj, H5VL_loc_params_t loc_params, const char *name,
 
     if(H5VL__iod_create_and_forward(H5VL_GROUP_OPEN_ID, HG_GROUP_OPEN, 
                                     (H5VL_iod_object_t *)grp, 1, 
-                                    input.axe_info.num_parents, parent_req,
+                                    num_parents, parent_reqs, (H5VL_iod_req_info_t *)rc,
                                     &input, &grp->remote_group, grp, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship group open");
 
     ret_value = (void *)grp;
 
 done:
-    if(new_name) 
-        free(new_name);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_group_open() */
 
@@ -1869,10 +1871,10 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5VL_iod_group_get(void *_grp, H5VL_group_get_t get_type, hid_t dxpl_id, void **req, va_list arguments)
+H5VL_iod_group_get(void *_grp, H5VL_group_get_t get_type, hid_t UNUSED dxpl_id, 
+                   void UNUSED **req, va_list arguments)
 {
     H5VL_iod_group_t *grp = (H5VL_iod_group_t *)_grp;
-    hbool_t do_async = (req == NULL) ? FALSE : TRUE; /* Whether we're performing async. I/O */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -1891,8 +1893,8 @@ H5VL_iod_group_get(void *_grp, H5VL_group_get_t get_type, hid_t dxpl_id, void **
         /* H5Gget_info */
         case H5VL_GROUP_GET_INFO:
             {
-                H5VL_loc_params_t loc_params = va_arg (arguments, H5VL_loc_params_t);
-                H5G_info_t *ginfo = va_arg (arguments, H5G_info_t *);
+                //H5VL_loc_params_t loc_params = va_arg (arguments, H5VL_loc_params_t);
+                //H5G_info_t *ginfo = va_arg (arguments, H5G_info_t *);
             }
         default:
             HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't get this type of information from group")
@@ -1916,13 +1918,12 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5VL_iod_group_close(void *_grp, hid_t dxpl_id, void **req)
+H5VL_iod_group_close(void *_grp, hid_t UNUSED dxpl_id, void **req)
 {
     H5VL_iod_group_t *grp = (H5VL_iod_group_t *)_grp;
     group_close_in_t input;
     int *status;
-    size_t num_parents;
-    AXE_task_t *parent_axe_ids = NULL;
+    size_t num_parents = 0;
     H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;                 /* Return value */
 
@@ -1935,42 +1936,36 @@ H5VL_iod_group_close(void *_grp, hid_t dxpl_id, void **req)
             HGOTO_ERROR(H5E_FILE,  H5E_CANTGET, FAIL, "can't wait on all object requests");
     }
 
-    if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)grp, &num_parents, NULL, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num AXE parents");
+    if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)grp, &num_parents, NULL) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num requests");
 
     if(num_parents) {
-        if(NULL == (parent_axe_ids = (AXE_task_t *)H5MM_malloc(sizeof(AXE_task_t) * num_parents)))
-            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent axe IDs");
-        if(NULL == (parent_reqs = (H5VL_iod_request_t **)H5MM_malloc
-                    (sizeof(H5VL_iod_request_t *) * num_parents)))
+        if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                    H5MM_malloc(sizeof(H5VL_iod_request_t *) * num_parents)))
             HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent reqs");
-        if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)grp, &num_parents, 
-                                    parent_axe_ids, parent_reqs) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get AXE parents");
+        if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)grp, &num_parents, 
+                                     parent_reqs) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get parent requests");
     }
 
     input.iod_oh = grp->remote_group.iod_oh;
     input.iod_id = grp->remote_group.iod_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = num_parents;
-    input.axe_info.parent_axe_ids = parent_axe_ids;
+
+    /* allocate an integer to receive the return value if the group close succeeded or not */
+    status = (int *)malloc(sizeof(int));
 
 #if H5VL_IOD_DEBUG
     printf("Group Close IOD ID %llu, axe id %llu\n", 
-           input.iod_id, input.axe_info.axe_id);
+           input.iod_id, g_axe_id);
 #endif
 
-    /* allocate an integer to receive the return value if the group close succeeded or not */
-    status = (int *)malloc(sizeof(int));
-
     if(H5VL__iod_create_and_forward(H5VL_GROUP_CLOSE_ID, HG_GROUP_CLOSE, 
                                     (H5VL_iod_object_t *)grp, 1,
                                     num_parents, parent_reqs,
-                                    &input, status, status, req) < 0)
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship group close");
 
 done:
-    parent_axe_ids = (AXE_task_t *)H5MM_xfree(parent_axe_ids);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_group_close() */
 
@@ -1989,17 +1984,20 @@ done:
  *-------------------------------------------------------------------------
  */
 static void *
-H5VL_iod_dataset_create(void *_obj, H5VL_loc_params_t loc_params, const char *name, hid_t dcpl_id, 
+H5VL_iod_dataset_create(void *_obj, H5VL_loc_params_t UNUSED loc_params, 
+                        const char *name, hid_t dcpl_id, 
                         hid_t dapl_id, hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location object to create the dataset */
     H5VL_iod_dset_t *dset = NULL; /* the dataset object that is created and passed to the user */
     dset_create_in_t input;
-    H5P_genplist_t *plist;
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    H5VL_iod_request_t **parent_req = NULL;
-    char *new_name = NULL; /* resolved path to where we need to start traversal at the server */
+    H5VL_iod_request_t **parent_reqs = NULL;
+    H5P_genplist_t *plist = NULL;
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
     hid_t type_id, space_id, lcpl_id;
     void *ret_value = NULL;
 
@@ -2017,13 +2015,29 @@ H5VL_iod_dataset_create(void *_obj, H5VL_loc_params_t loc_params, const char *na
     if(H5P_get(plist, H5VL_DSET_LCPL_ID, &lcpl_id) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for lcpl id");
 
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, NULL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a Transaction ID")
+
     /* Retrieve the parent AXE id by traversing the path where the
        dataset should be created. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, name, &iod_id, &iod_oh, 
-                                parent_req, &new_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current working group");
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current location group info");
 
     /* allocate the dataset object that is returned to the user */
     if(NULL == (dset = H5FL_CALLOC(H5VL_iod_dset_t)))
@@ -2045,26 +2059,14 @@ H5VL_iod_dataset_create(void *_obj, H5VL_loc_params_t loc_params, const char *na
     input.coh = obj->file->remote_file.coh;
     input.loc_id = iod_id;
     input.loc_oh = iod_oh;
-    input.name = new_name;
+    input.name = name;
     input.dcpl_id = dcpl_id;
     input.dapl_id = dapl_id;
     input.lcpl_id = lcpl_id;
     input.type_id = type_id;
     input.space_id = space_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
-
-#if H5VL_IOD_DEBUG
-    printf("Dataset Create %s IOD ID %llu, axe id %llu, parent %llu\n", 
-           new_name, input.dset_id, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
-#endif
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
     /* setup the local dataset struct */
     /* store the entire path of the dataset locally */
@@ -2094,17 +2096,20 @@ H5VL_iod_dataset_create(void *_obj, H5VL_loc_params_t loc_params, const char *na
     dset->common.file = obj->file;
     dset->common.file->nopen_objs ++;
 
+#if H5VL_IOD_DEBUG
+    printf("Dataset Create %s IOD ID %llu, axe id %llu\n", 
+           name, input.dset_id, g_axe_id);
+#endif
+
     if(H5VL__iod_create_and_forward(H5VL_DSET_CREATE_ID, HG_DSET_CREATE, 
                                     (H5VL_iod_object_t *)dset, 1, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, &dset->remote_dset, dset, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)tr, &input, &dset->remote_dset, dset, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship dataset create");
 
     ret_value = (void *)dset;
 
 done:
-    if(new_name) 
-        free(new_name);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_dataset_create() */
 
@@ -2123,7 +2128,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static void *
-H5VL_iod_dataset_open(void *_obj, H5VL_loc_params_t loc_params, const char *name, 
+H5VL_iod_dataset_open(void *_obj, H5VL_loc_params_t UNUSED loc_params, const char *name, 
                       hid_t dapl_id, hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location object to create the dataset */
@@ -2131,19 +2136,38 @@ H5VL_iod_dataset_open(void *_obj, H5VL_loc_params_t loc_params, const char *name
     dset_open_in_t input;
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    H5VL_iod_request_t **parent_req = NULL;
-    char *new_name = NULL; /* resolved path to where we need to start traversal at the server */
+    H5P_genplist_t *plist = NULL;
+    hid_t rcxt_id;
+    H5RC_t *rc;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     void *ret_value = NULL;
 
     FUNC_ENTER_NOAPI_NOINIT
 
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, NULL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for trans_id");
+
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a READ CONTEXT ID")
+
     /* Retrieve the parent AXE id by traversing the path where the
        dataset should be opened. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, name, &iod_id, &iod_oh, 
-                                parent_req, &new_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current working group");
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)rc, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current location group info");
 
     /* allocate the dataset object that is returned to the user */
     if(NULL == (dset = H5FL_CALLOC(H5VL_iod_dset_t)))
@@ -2159,22 +2183,9 @@ H5VL_iod_dataset_open(void *_obj, H5VL_loc_params_t loc_params, const char *name
     input.coh = obj->file->remote_file.coh;
     input.loc_id = iod_id;
     input.loc_oh = iod_oh;
-    input.name = new_name;
+    input.name = name;
     input.dapl_id = dapl_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
-
-#if H5VL_IOD_DEBUG
-    printf("Dataset Open %s LOC ID %llu, axe id %llu, parent %llu\n", 
-           new_name, input.loc_id, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
-#endif
+    input.rcxt_num  = rc->c_version;
 
     /* setup the local dataset struct */
     /* store the entire path of the dataset locally */
@@ -2197,17 +2208,20 @@ H5VL_iod_dataset_open(void *_obj, H5VL_loc_params_t loc_params, const char *name
     dset->common.file = obj->file;
     dset->common.file->nopen_objs ++;
 
+#if H5VL_IOD_DEBUG
+    printf("Dataset Open %s LOC ID %llu, axe id %llu\n", 
+           name, input.loc_id, g_axe_id);
+#endif
+
     if(H5VL__iod_create_and_forward(H5VL_DSET_OPEN_ID, HG_DSET_OPEN, 
                                     (H5VL_iod_object_t *)dset, 1, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, &dset->remote_dset, dset, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)rc, &input, &dset->remote_dset, dset, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship dataset open");
 
     ret_value = (void *)dset;
 
 done:
-    if(new_name) 
-        free(new_name);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_dataset_open() */
 
@@ -2232,7 +2246,7 @@ H5VL_iod_dataset_read(void *_dset, hid_t mem_type_id, hid_t mem_space_id,
     H5VL_iod_dset_t *dset = (H5VL_iod_dset_t *)_dset;
     dset_io_in_t input;
     dset_get_vl_size_in_t input_vl;
-    H5P_genplist_t *plist;
+    H5P_genplist_t *plist = NULL;
     hg_bulk_t *bulk_handle = NULL;
     H5VL_iod_read_status_t *status = NULL;
     const H5S_t *mem_space = NULL;
@@ -2242,11 +2256,24 @@ H5VL_iod_dataset_read(void *_dset, hid_t mem_type_id, hid_t mem_space_id,
     size_t nelmts;    /* num elements in mem dataspace */
     H5VL_iod_io_info_t *info = NULL;
     hbool_t is_vl_data = FALSE;
-    H5VL_iod_request_t **parent_req = NULL;
+    hid_t rcxt_id;
+    H5RC_t *rc;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
+    /* get the context ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a READ CONTEXT ID")
+
     /* If there is information needed about the dataset that is not present locally, wait */
     if(-1 == dset->remote_dset.dcpl_id ||
        -1 == dset->remote_dset.type_id ||
@@ -2303,9 +2330,15 @@ H5VL_iod_dataset_read(void *_dset, hid_t mem_type_id, hid_t mem_space_id,
                          bulk_handle, &is_vl_data) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "can't generate read parameters");
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests((H5VL_iod_object_t *)dset, (H5VL_iod_req_info_t *)rc, 
+                                    parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
     if(!is_vl_data) {
         /* Fill input structure for reading data */
         input.coh = dset->common.file->remote_file.coh;
@@ -2317,18 +2350,7 @@ H5VL_iod_dataset_read(void *_dset, hid_t mem_type_id, hid_t mem_space_id,
         input.space_id = file_space_id;
         input.dset_type_id = dset->remote_dset.type_id;
         input.mem_type_id = mem_type_id;
-        input.axe_info.axe_id = g_axe_id ++;
-        if(NULL != dset->common.request && dset->common.request->state != H5VL_IOD_COMPLETED) {
-            input.axe_info.num_parents = 1;
-            input.axe_info.parent_axe_ids = &dset->common.request->axe_id;
-            dset->common.request->ref_count ++;
-            *parent_req = dset->common.request;
-        }
-        else {
-            input.axe_info.num_parents = 0;
-            input.axe_info.parent_axe_ids = NULL;
-            *parent_req = NULL;
-        }
+        input.rcxt_num  = rc->c_version;
     }
     else {
         /* Fill input structure for retrieving the buffer size needed to read */
@@ -2338,33 +2360,13 @@ H5VL_iod_dataset_read(void *_dset, hid_t mem_type_id, hid_t mem_space_id,
         input_vl.dxpl_id = dxpl_id;
         input_vl.space_id = file_space_id;
         input_vl.mem_type_id = mem_type_id;
-        input_vl.axe_info.axe_id = g_axe_id ++;
-        if(NULL != dset->common.request && dset->common.request->state != H5VL_IOD_COMPLETED) {
-            input_vl.axe_info.num_parents = 1;
-            input_vl.axe_info.parent_axe_ids = &dset->common.request->axe_id;
-            dset->common.request->ref_count ++;
-            *parent_req = dset->common.request;
-        }
-        else {
-            input_vl.axe_info.num_parents = 0;
-            input_vl.axe_info.parent_axe_ids = NULL;
-            *parent_req = NULL;
-        }
+        input_vl.rcxt_num  = rc->c_version;
     }
 
     /* allocate structure to receive status of read operation
        (contains return value, checksum, and buffer size) */
     status = (H5VL_iod_read_status_t *)malloc(sizeof(H5VL_iod_read_status_t));
 
-#if H5VL_IOD_DEBUG
-    if(!is_vl_data)
-        printf("Dataset Read, axe id %llu, parent %llu\n", 
-               input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
-    else
-        printf("Dataset GET size, axe id %llu, parent %llu\n", 
-               input_vl.axe_info.axe_id, ((input_vl.axe_info.parent_axe_ids!=NULL) ? input_vl.axe_info.parent_axe_ids[0] : 0));
-#endif
-
     /* setup info struct for I/O request. 
        This is to manage the I/O operation once the wait is called. */
     if(NULL == (info = (H5VL_iod_io_info_t *)H5MM_calloc(sizeof(H5VL_iod_io_info_t))))
@@ -2397,23 +2399,30 @@ H5VL_iod_dataset_read(void *_dset, hid_t mem_type_id, hid_t mem_space_id,
             HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to copy datatype");
         if((info->dxpl_id = H5P_copy_plist((H5P_genplist_t *)plist, TRUE)) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTINIT, FAIL, "unable to copy dxpl");
-        info->axe_id = g_axe_id ++;
+
         info->peer = PEER;
         info->read_id = H5VL_DSET_READ_ID;
     }
 
+#if H5VL_IOD_DEBUG
+    if(!is_vl_data)
+        printf("Dataset Read, axe id %llu\n", g_axe_id);
+    else
+        printf("Dataset GET size, axe id %llu\n", g_axe_id);
+#endif
+
     /* forward the call to the IONs */
     if(!is_vl_data) {
         if(H5VL__iod_create_and_forward(H5VL_DSET_READ_ID, HG_DSET_READ, 
                                         (H5VL_iod_object_t *)dset, 0,
-                                        input.axe_info.num_parents, parent_req,
+                                        num_parents, parent_reqs, (H5VL_iod_req_info_t *)rc, 
                                         &input, status, info, req) < 0)
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship dataset read");
     }
     else {
         if(H5VL__iod_create_and_forward(H5VL_DSET_GET_VL_SIZE_ID, HG_DSET_GET_VL_SIZE, 
                                         (H5VL_iod_object_t *)dset, 0,
-                                        input_vl.axe_info.num_parents, parent_req,
+                                        num_parents, parent_reqs, (H5VL_iod_req_info_t *)rc,
                                         &input_vl, status, info, req) < 0)
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship dataset get VL size");
     }
@@ -2442,19 +2451,19 @@ H5VL_iod_dataset_write(void *_dset, hid_t mem_type_id, hid_t mem_space_id,
 {
     H5VL_iod_dset_t *dset = (H5VL_iod_dset_t *)_dset;
     dset_io_in_t input;
-    H5P_genplist_t *plist;
+    H5P_genplist_t *plist = NULL;
     hg_bulk_t *bulk_handle = NULL;
     const H5S_t *mem_space = NULL;
     const H5S_t *file_space = NULL;
     char fake_char;
     int *status = NULL;
-    hsize_t buf_size;  /* size of the contiguous buffer */
-    size_t type_size; /* size of mem type */
-    size_t nelmts;    /* num elements in mem dataspace */
     H5VL_iod_io_info_t *info; /* info struct used to manage I/O parameters once the operation completes*/
     uint32_t internal_cs; /* internal checksum calculated in this function */
     size_t *vl_string_len = NULL; /* array that will contain lengths of strings if the datatype is a VL string type */
-    H5VL_iod_request_t **parent_req = NULL;
+    H5VL_iod_request_t **parent_reqs = NULL;
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -2502,14 +2511,20 @@ H5VL_iod_dataset_write(void *_dset, hid_t mem_type_id, hid_t mem_space_id,
                           &internal_cs, bulk_handle, &vl_string_len) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "can't generate write parameters");
 
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Transaction ID")
+
     /* Verify the checksum value if the dxpl contains a user defined checksum */
     if(H5P_DATASET_XFER_DEFAULT != dxpl_id) {
         uint32_t user_cs;
 
-        /* Get the dcpl plist structure */
-        if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
-            HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
-
         if(H5P_get(plist, H5D_XFER_CHECKSUM_NAME, &user_cs) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to get checksum value");
 
@@ -2520,9 +2535,15 @@ H5VL_iod_dataset_write(void *_dset, hid_t mem_type_id, hid_t mem_space_id,
         }
     }
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests((H5VL_iod_object_t *)dset, (H5VL_iod_req_info_t *)tr, 
+                                    parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
     /* Fill input structure */
     input.coh = dset->common.file->remote_file.coh;
     input.iod_oh = dset->remote_dset.iod_oh;
@@ -2533,24 +2554,13 @@ H5VL_iod_dataset_write(void *_dset, hid_t mem_type_id, hid_t mem_space_id,
     input.space_id = file_space_id;
     input.dset_type_id = dset->remote_dset.type_id;
     input.mem_type_id = mem_type_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != dset->common.request && dset->common.request->state != H5VL_IOD_COMPLETED) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &dset->common.request->axe_id;
-        dset->common.request->ref_count ++;
-        *parent_req = dset->common.request;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-        *parent_req = NULL;
-    }
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
     status = (int *)malloc(sizeof(int));
 
 #if H5VL_IOD_DEBUG
-    printf("Dataset Write, axe id %llu, parent %llu\n", 
-           input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Dataset Write, axe id %llu\n", g_axe_id);
 #endif
 
     /* setup info struct for I/O request 
@@ -2564,8 +2574,8 @@ H5VL_iod_dataset_write(void *_dset, hid_t mem_type_id, hid_t mem_space_id,
 
     if(H5VL__iod_create_and_forward(H5VL_DSET_WRITE_ID, HG_DSET_WRITE, 
                                     (H5VL_iod_object_t *)dset, 0,
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, status, info, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)tr, &input, status, info, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship dataset write");
 
 done:
@@ -2587,15 +2597,16 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t 
-H5VL_iod_dataset_set_extent(void *_dset, const hsize_t size[], hid_t dxpl_id, void **req)
+H5VL_iod_dataset_set_extent(void *_dset, const hsize_t size[], 
+                            hid_t dxpl_id, void **req)
 {
     H5VL_iod_dset_t *dset = (H5VL_iod_dset_t *)_dset;
     dset_set_extent_in_t input;
-    iod_obj_id_t iod_id;
-    iod_handle_t iod_oh;
     int *status = NULL;
-    size_t num_parents;
-    AXE_task_t *parent_axe_ids = NULL;
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
+    H5P_genplist_t *plist = NULL;
     H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;    /* Return value */
 
@@ -2609,18 +2620,26 @@ H5VL_iod_dataset_set_extent(void *_dset, const hsize_t size[], hid_t dxpl_id, vo
         dset->common.request = NULL;
     }
 
-    if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)dset, &num_parents, NULL, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num AXE parents");
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Transaction ID")
+
+    if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)dset, &num_parents, NULL) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num requests");
 
     if(num_parents) {
-        if(NULL == (parent_axe_ids = (AXE_task_t *)H5MM_malloc(sizeof(AXE_task_t) * num_parents)))
-            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent axe IDs");
         if(NULL == (parent_reqs = (H5VL_iod_request_t **)H5MM_malloc
                     (sizeof(H5VL_iod_request_t *) * num_parents)))
             HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent reqs");
-        if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)dset, &num_parents, 
-                                    parent_axe_ids, parent_reqs) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get AXE parents");
+        if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)dset, &num_parents, 
+                                     parent_reqs) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get parent requests");
     }
 
     /* Fill input structure */
@@ -2629,20 +2648,11 @@ H5VL_iod_dataset_set_extent(void *_dset, const hsize_t size[], hid_t dxpl_id, vo
     input.iod_id = dset->remote_dset.iod_id;
     input.dims.rank = H5Sget_simple_extent_ndims(dset->remote_dset.space_id);
     input.dims.size = size;
-    input.axe_info.num_parents = num_parents;
-    input.axe_info.parent_axe_ids = parent_axe_ids;
-    input.axe_info.axe_id = g_axe_id ++;
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
 #if H5VL_IOD_DEBUG
-    {
-        size_t i;
-
-        printf("Dataset Set Extent, axe id %llu, %d parents: ", 
-               input.axe_info.axe_id, num_parents);
-        for(i=0 ; i<num_parents ; i++)
-            printf("%llu ", parent_axe_ids[i]);
-        printf("\n");
-    }
+    printf("Dataset Set Extent, axe id %llu\n", g_axe_id);
 #endif
 
     status = (int *)malloc(sizeof(int));
@@ -2650,7 +2660,7 @@ H5VL_iod_dataset_set_extent(void *_dset, const hsize_t size[], hid_t dxpl_id, vo
     if(H5VL__iod_create_and_forward(H5VL_DSET_SET_EXTENT_ID, HG_DSET_SET_EXTENT, 
                                     (H5VL_iod_object_t *)dset, 1,
                                     num_parents, parent_reqs,
-                                    &input, status, status, req) < 0)
+                                    (H5VL_iod_req_info_t *)tr, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship dataset set_extent");
 
     /* modify the local dataspace of the dataset */
@@ -2672,7 +2682,6 @@ H5VL_iod_dataset_set_extent(void *_dset, const hsize_t size[], hid_t dxpl_id, vo
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to modify size of data space");
     }
 done:
-    parent_axe_ids = (AXE_task_t *)H5MM_xfree(parent_axe_ids);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_dataset_set_extent() */
 
@@ -2691,8 +2700,9 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5VL_iod_dataset_get(void *_dset, H5VL_dataset_get_t get_type, hid_t dxpl_id, 
-                     void **req, va_list arguments)
+H5VL_iod_dataset_get(void *_dset, H5VL_dataset_get_t get_type, 
+                     hid_t UNUSED dxpl_id, 
+                     void UNUSED **req, va_list arguments)
 {
     H5VL_iod_dset_t *dset = (H5VL_iod_dset_t *)_dset;
     herr_t       ret_value = SUCCEED;    /* Return value */
@@ -2776,13 +2786,12 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5VL_iod_dataset_close(void *_dset, hid_t dxpl_id, void **req)
+H5VL_iod_dataset_close(void *_dset, hid_t UNUSED dxpl_id, void **req)
 {
     H5VL_iod_dset_t *dset = (H5VL_iod_dset_t *)_dset;
     dset_close_in_t input;
     int *status;
-    size_t num_parents;
-    AXE_task_t *parent_axe_ids = NULL;
+    size_t num_parents = 0;
     H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;  /* Return value */
 
@@ -2804,48 +2813,35 @@ H5VL_iod_dataset_close(void *_dset, hid_t dxpl_id, void **req)
             HGOTO_ERROR(H5E_DATASET,  H5E_CANTGET, FAIL, "can't wait on all object requests");
     }
 
-    if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)dset, &num_parents, NULL, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num AXE parents");
+    if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)dset, &num_parents, NULL) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num requests");
 
     if(num_parents) {
-        if(NULL == (parent_axe_ids = (AXE_task_t *)H5MM_malloc(sizeof(AXE_task_t) * num_parents)))
-            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent axe IDs");
         if(NULL == (parent_reqs = (H5VL_iod_request_t **)H5MM_malloc
                     (sizeof(H5VL_iod_request_t *) * num_parents)))
             HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent reqs");
-        if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)dset, &num_parents, 
-                                    parent_axe_ids, parent_reqs) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get AXE parents");
+        if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)dset, &num_parents, 
+                                     parent_reqs) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get parent requests");
     }
 
     input.iod_oh = dset->remote_dset.iod_oh;
     input.iod_id = dset->remote_dset.iod_id;
-    input.axe_info.num_parents = num_parents;
-    input.axe_info.parent_axe_ids = parent_axe_ids;
-    input.axe_info.axe_id = g_axe_id ++;
 
-#if H5VL_IOD_DEBUG
-    {
-        size_t i;
+    status = (int *)malloc(sizeof(int));
 
-        printf("Dataset Close %s, axe id %llu, %d parents: ", 
-               dset->common.obj_name, input.axe_info.axe_id, num_parents);
-        for(i=0 ; i<num_parents ; i++)
-            printf("%llu ", parent_axe_ids[i]);
-        printf("\n");
-    }
+#if H5VL_IOD_DEBUG
+    printf("Dataset Close IOD ID %llu, axe id %llu\n", 
+           input.iod_id, g_axe_id);
 #endif
 
-    status = (int *)malloc(sizeof(int));
-
     if(H5VL__iod_create_and_forward(H5VL_DSET_CLOSE_ID, HG_DSET_CLOSE, 
                                     (H5VL_iod_object_t *)dset, 1,
                                     num_parents, parent_reqs,
-                                    &input, status, status, req) < 0)
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship dataset close");
 
 done:
-    parent_axe_ids = (AXE_task_t *)H5MM_xfree(parent_axe_ids);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_dataset_close() */
 
@@ -2864,7 +2860,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static void *
-H5VL_iod_datatype_commit(void *_obj, H5VL_loc_params_t loc_params, const char *name, 
+H5VL_iod_datatype_commit(void *_obj, H5VL_loc_params_t UNUSED loc_params, const char *name, 
                          hid_t type_id, hid_t lcpl_id, hid_t tcpl_id, hid_t tapl_id, 
                          hid_t dxpl_id, void **req)
 {
@@ -2873,19 +2869,37 @@ H5VL_iod_datatype_commit(void *_obj, H5VL_loc_params_t loc_params, const char *n
     dtype_commit_in_t input;
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    char *new_name = NULL; /* resolved path to where we need to start traversal at the server */
-    H5VL_iod_request_t **parent_req = NULL;
+    H5P_genplist_t *plist = NULL;
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
+    H5VL_iod_request_t **parent_reqs = NULL;
     void *ret_value = NULL;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    /* Retrieve the parent AXE id by traversing the path where the
-       dtype should be created. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, name, &iod_id, &iod_oh, 
-                                parent_req, &new_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current working group");
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, NULL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a Transaction ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current location group info");
 
     /* allocate the datatype object that is returned to the user */
     if(NULL == (dtype = H5FL_CALLOC(H5VL_iod_dtype_t)))
@@ -2907,24 +2921,17 @@ H5VL_iod_datatype_commit(void *_obj, H5VL_loc_params_t loc_params, const char *n
     input.coh = obj->file->remote_file.coh;
     input.loc_id = iod_id;
     input.loc_oh = iod_oh;
-    input.name = new_name;
+    input.name = name;
     input.tcpl_id = tcpl_id;
     input.tapl_id = tapl_id;
     input.lcpl_id = lcpl_id;
     input.type_id = type_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
 #if H5VL_IOD_DEBUG
-    printf("Datatype Commit %s IOD ID %llu, axe id %llu, parent %llu\n", 
-           new_name, input.dtype_id, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Datatype Commit %s IOD ID %llu, axe id %llu\n", 
+           name, input.dtype_id, g_axe_id);
 #endif
 
     /* setup the local datatype struct */
@@ -2955,14 +2962,13 @@ H5VL_iod_datatype_commit(void *_obj, H5VL_loc_params_t loc_params, const char *n
 
     if(H5VL__iod_create_and_forward(H5VL_DTYPE_COMMIT_ID, HG_DTYPE_COMMIT, 
                                     (H5VL_iod_object_t *)dtype, 1, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, &dtype->remote_dtype, dtype, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)tr, &input, &dtype->remote_dtype, dtype, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship datatype commit");
 
     ret_value = (void *)dtype;
+
 done:
-    if(new_name) 
-        free(new_name);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_datatype_commit() */
 
@@ -2981,7 +2987,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static void *
-H5VL_iod_datatype_open(void *_obj, H5VL_loc_params_t loc_params, const char *name, 
+H5VL_iod_datatype_open(void *_obj, H5VL_loc_params_t UNUSED loc_params, const char *name, 
                        hid_t tapl_id, hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location object to create the datatype */
@@ -2989,19 +2995,37 @@ H5VL_iod_datatype_open(void *_obj, H5VL_loc_params_t loc_params, const char *nam
     dtype_open_in_t input;
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    char *new_name = NULL; /* resolved path to where we need to start traversal at the server */
-    H5VL_iod_request_t **parent_req = NULL;
+    H5P_genplist_t *plist = NULL;
+    hid_t rcxt_id;
+    H5RC_t *rc;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     void *ret_value = NULL;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    /* Retrieve the parent AXE id by traversing the path where the
-       dtype should be opened. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, name, &iod_id, &iod_oh, 
-                                parent_req, &new_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current working group");
+    /* get the context ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, NULL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for trans_id");
+
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a READ CONTEXT ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)rc, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current location group info");
 
     /* allocate the datatype object that is returned to the user */
     if(NULL == (dtype = H5FL_CALLOC(H5VL_iod_dtype_t)))
@@ -3016,21 +3040,13 @@ H5VL_iod_datatype_open(void *_obj, H5VL_loc_params_t loc_params, const char *nam
     input.coh = obj->file->remote_file.coh;
     input.loc_id = iod_id;
     input.loc_oh = iod_oh;
-    input.name = new_name;
+    input.name = name;
     input.tapl_id = tapl_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
+    input.rcxt_num  = rc->c_version;
 
 #if H5VL_IOD_DEBUG
-    printf("Datatype Open %s LOC ID %llu, axe id %llu, parent %llu\n", 
-           new_name, input.loc_id, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Datatype Open %s LOC ID %llu, axe id %llu\n", 
+           name, input.loc_id, g_axe_id);
 #endif
 
     /* setup the local datatype struct */
@@ -3056,14 +3072,13 @@ H5VL_iod_datatype_open(void *_obj, H5VL_loc_params_t loc_params, const char *nam
 
     if(H5VL__iod_create_and_forward(H5VL_DTYPE_OPEN_ID, HG_DTYPE_OPEN, 
                                     (H5VL_iod_object_t *)dtype, 1, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, &dtype->remote_dtype, dtype, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)rc, &input, &dtype->remote_dtype, dtype, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship datatype open");
 
     ret_value = (void *)dtype;
 
 done:
-    if(new_name) free(new_name);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_datatype_open() */
 
@@ -3152,12 +3167,11 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5VL_iod_datatype_close(void *obj, hid_t dxpl_id, void **req)
+H5VL_iod_datatype_close(void *obj, hid_t UNUSED dxpl_id, void **req)
 {
     H5VL_iod_dtype_t *dtype = (H5VL_iod_dtype_t *)obj;
     dtype_close_in_t input;
-    size_t num_parents;
-    AXE_task_t *parent_axe_ids = NULL;
+    size_t num_parents = 0;
     H5VL_iod_request_t **parent_reqs = NULL;
     int *status;
     herr_t ret_value = SUCCEED;  /* Return value */
@@ -3171,29 +3185,23 @@ H5VL_iod_datatype_close(void *obj, hid_t dxpl_id, void **req)
             HGOTO_ERROR(H5E_FILE,  H5E_CANTGET, FAIL, "can't wait on all object requests");
     }
 
-    if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)dtype, &num_parents, NULL, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num AXE parents");
+    if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)dtype, &num_parents, NULL) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num requests");
 
     if(num_parents) {
-        if(NULL == (parent_axe_ids = (AXE_task_t *)H5MM_malloc(sizeof(AXE_task_t) * num_parents)))
-            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent axe IDs");
-        if(NULL == (parent_reqs = (H5VL_iod_request_t **)H5MM_malloc
-                    (sizeof(H5VL_iod_request_t *) * num_parents)))
+        if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                    H5MM_malloc(sizeof(H5VL_iod_request_t *) * num_parents)))
             HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent reqs");
-        if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)dtype, &num_parents, 
-                                    parent_axe_ids, parent_reqs) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get AXE parents");
+        if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)dtype, &num_parents, 
+                                    parent_reqs) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get parent requests");
     }
 
     input.iod_oh = dtype->remote_dtype.iod_oh;
     input.iod_id = dtype->remote_dtype.iod_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = num_parents;
-    input.axe_info.parent_axe_ids = parent_axe_ids;
 
 #if H5VL_IOD_DEBUG
-    printf("Datatype Close %s, axe id %llu, parent %llu\n", 
-           dtype->common.obj_name, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Datatype Close IOD ID %llu, axe id %llu\n", input.iod_id, g_axe_id);
 #endif
 
     status = (int *)malloc(sizeof(int));
@@ -3201,11 +3209,10 @@ H5VL_iod_datatype_close(void *obj, hid_t dxpl_id, void **req)
     if(H5VL__iod_create_and_forward(H5VL_DTYPE_CLOSE_ID, HG_DTYPE_CLOSE, 
                                     (H5VL_iod_object_t *)dtype, 1,
                                     num_parents, parent_reqs,
-                                    &input, status, status, req) < 0)
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship datatype open");
 
 done:
-    parent_axe_ids = (AXE_task_t *)H5MM_xfree(parent_axe_ids);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_datatype_close() */
 
@@ -3225,18 +3232,21 @@ done:
  */
 static void *
 H5VL_iod_attribute_create(void *_obj, H5VL_loc_params_t loc_params, const char *attr_name, 
-                          hid_t acpl_id, hid_t aapl_id, hid_t dxpl_id, void **req)
+                          hid_t acpl_id, hid_t UNUSED aapl_id, hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location object to create the attribute */
     H5VL_iod_attr_t *attr = NULL; /* the attribute object that is created and passed to the user */
     attr_create_in_t input;
-    H5P_genplist_t *plist;
+    H5P_genplist_t *plist = NULL;
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    char *new_name = NULL;   /* resolved path to where we need to start traversal at the server */
     const char *path; /* path on where the traversal starts relative to the location object specified */
+    char *loc_name = NULL;
     hid_t type_id, space_id;
-    H5VL_iod_request_t **parent_req = NULL;
+    H5VL_iod_request_t **parent_reqs = NULL;
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
     void *ret_value = NULL;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -3251,13 +3261,28 @@ H5VL_iod_attribute_create(void *_obj, H5VL_loc_params_t loc_params, const char *
     if(H5P_get(plist, H5VL_ATTR_SPACE_ID, &space_id) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for space id");
 
-    /* Retrieve the parent AXE id by traversing the path where the
-       attribute should be created. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, ".", &iod_id, &iod_oh, 
-                                parent_req, &new_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current working group");
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, NULL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a Transaction ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current location group info");
 
     /* allocate the attribute object that is returned to the user */
     if(NULL == (attr = H5FL_CALLOC(H5VL_iod_attr_t)))
@@ -3275,24 +3300,22 @@ H5VL_iod_attribute_create(void *_obj, H5VL_loc_params_t loc_params, const char *
     /* increment the index of ARRAY objects created on the container */
     obj->file->remote_file.array_oid_index ++;
 
+    if(H5VL_OBJECT_BY_SELF == loc_params.type)
+        loc_name = strdup(".");
+    else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+        loc_name = strdup(loc_params.loc_data.loc_by_name.name);
+
     /* set the input structure for the HG encode routine */
     input.coh = obj->file->remote_file.coh;
     input.loc_id = iod_id;
     input.loc_oh = iod_oh;
-    input.path = new_name;
+    input.path = loc_name;
     input.attr_name = attr_name;
     input.acpl_id = acpl_id;
     input.type_id = type_id;
     input.space_id = space_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
     /* setup the local attribute struct */
     /* store the entire path of the attribute locally */
@@ -3318,8 +3341,8 @@ H5VL_iod_attribute_create(void *_obj, H5VL_loc_params_t loc_params, const char *
     attr->common.obj_name = strdup(attr_name);
 
 #if H5VL_IOD_DEBUG
-    printf("Attribute Create %s IOD ID %llu, axe id %llu, parent %llu\n", 
-           attr_name, input.attr_id, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Attribute Create %s IOD ID %llu, axe id %llu\n", 
+           attr_name, input.attr_id, g_axe_id);
 #endif
 
     /* copy property lists, dtype, and dspace*/
@@ -3337,15 +3360,16 @@ H5VL_iod_attribute_create(void *_obj, H5VL_loc_params_t loc_params, const char *
 
     if(H5VL__iod_create_and_forward(H5VL_ATTR_CREATE_ID, HG_ATTR_CREATE, 
                                     (H5VL_iod_object_t *)attr, 1, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, &attr->remote_attr, attr, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)tr, &input, &attr->remote_attr, attr, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship attribute create");
 
     ret_value = (void *)attr;
 
 done:
-    if(new_name) 
-        free(new_name);
+    if(loc_name) 
+        HDfree(loc_name);
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_attribute_create() */
 
@@ -3365,27 +3389,46 @@ done:
  */
 static void *
 H5VL_iod_attribute_open(void *_obj, H5VL_loc_params_t loc_params, const char *attr_name, 
-                        hid_t aapl_id, hid_t dxpl_id, void **req)
+                        hid_t UNUSED aapl_id, hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location object to create the attribute */
     H5VL_iod_attr_t *attr = NULL; /* the attribute object that is created and passed to the user */
     attr_open_in_t input;
-    char *new_name = NULL;   /* resolved path to where we need to start traversal at the server */
     const char *path; /* path on where the traversal starts relative to the location object specified */
+    char *loc_name = NULL;
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    H5VL_iod_request_t **parent_req = NULL;
+    H5P_genplist_t *plist = NULL;
+    hid_t rcxt_id;
+    H5RC_t *rc;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     void *ret_value = NULL;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    /* Retrieve the parent AXE id by traversing the path where the
-       attribute should be opened. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, ".", &iod_id, &iod_oh, 
-                                parent_req, &new_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current working group");
+    /* get the context ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, NULL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for trans_id");
+
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a READ CONTEXT ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)rc, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current location group info");
 
     /* allocate the attribute object that is returned to the user */
     if(NULL == (attr = H5FL_CALLOC(H5VL_iod_attr_t)))
@@ -3397,25 +3440,22 @@ H5VL_iod_attribute_open(void *_obj, H5VL_loc_params_t loc_params, const char *at
     attr->remote_attr.type_id = -1;
     attr->remote_attr.space_id = -1;
 
+    if(H5VL_OBJECT_BY_SELF == loc_params.type)
+        loc_name = strdup(".");
+    else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+        loc_name = strdup(loc_params.loc_data.loc_by_name.name);
+
     /* set the input structure for the HG encode routine */
     input.coh = obj->file->remote_file.coh;
     input.loc_id = iod_id;
     input.loc_oh = iod_oh;
-    input.path = new_name;
+    input.path = loc_name;
     input.attr_name = attr_name;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
+    input.rcxt_num  = rc->c_version;
 
 #if H5VL_IOD_DEBUG
-    printf("Attribute Open %s LOC ID %llu, axe id %llu, parent %llu\n", 
-           attr_name, input.loc_id, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Attribute Open %s LOC ID %llu, axe id %llu\n", 
+           attr_name, input.loc_id, g_axe_id);
 #endif
 
     /* setup the local attribute struct */
@@ -3449,15 +3489,15 @@ H5VL_iod_attribute_open(void *_obj, H5VL_loc_params_t loc_params, const char *at
 
     if(H5VL__iod_create_and_forward(H5VL_ATTR_OPEN_ID, HG_ATTR_OPEN, 
                                     (H5VL_iod_object_t *)attr, 1, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, &attr->remote_attr, attr, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)rc, &input, &attr->remote_attr, attr, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship attribute open");
 
     ret_value = (void *)attr;
 
 done:
-    if(new_name) 
-        free(new_name);
+    if(loc_name) 
+        HDfree(loc_name);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_attribute_open() */
 
@@ -3483,12 +3523,26 @@ H5VL_iod_attribute_read(void *_attr, hid_t type_id, void *buf, hid_t dxpl_id, vo
     hg_bulk_t *bulk_handle = NULL;
     H5VL_iod_read_status_t *status = NULL;
     size_t size;
-    H5VL_iod_io_info_t *info;
-    H5VL_iod_request_t **parent_req = NULL;
+    H5VL_iod_io_info_t *info = NULL;
+    hid_t rcxt_id;
+    H5RC_t *rc;
+    size_t num_parents = 0;
+    H5P_genplist_t *plist = NULL;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
+    /* get the context ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a READ CONTEXT ID")
+
     if(-1 == attr->remote_attr.space_id) {
         HDassert(attr->common.request);
         /* Synchronously wait on the request attached to the attribute */
@@ -3508,27 +3562,22 @@ H5VL_iod_attribute_read(void *_attr, hid_t type_id, void *buf, hid_t dxpl_id, vo
     if(HG_SUCCESS != HG_Bulk_handle_create(buf, size, HG_BULK_READWRITE, bulk_handle))
         HGOTO_ERROR(H5E_ATTR, H5E_READERROR, FAIL, "can't create Bulk Data Handle");
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests((H5VL_iod_object_t *)attr, (H5VL_iod_req_info_t *)rc, 
+                                    parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
     /* Fill input structure */
     input.coh = attr->common.file->remote_file.coh;
     input.iod_oh = attr->remote_attr.iod_oh;
     input.iod_id = attr->remote_attr.iod_id;
     input.bulk_handle = *bulk_handle;
     input.type_id = type_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != attr->common.request && attr->common.request->state != H5VL_IOD_COMPLETED) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &attr->common.request->axe_id;
-        attr->common.request->ref_count ++;
-        *parent_req = attr->common.request;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-        *parent_req = NULL;
-    }
+    input.rcxt_num  = rc->c_version;
 
     /* allocate structure to receive status of read operation (contains return value and checksum */
     status = (H5VL_iod_read_status_t *)malloc(sizeof(H5VL_iod_read_status_t));
@@ -3542,8 +3591,8 @@ H5VL_iod_attribute_read(void *_attr, hid_t type_id, void *buf, hid_t dxpl_id, vo
 
     if(H5VL__iod_create_and_forward(H5VL_ATTR_READ_ID, HG_ATTR_READ, 
                                     (H5VL_iod_object_t *)attr, 0,
-                                    input.axe_info.num_parents, parent_req, 
-                                    &input, status, info, req) < 0)
+                                    num_parents, parent_reqs, 
+                                    (H5VL_iod_req_info_t *)rc, &input, status, info, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship attribute read");
 
 done:
@@ -3569,17 +3618,30 @@ H5VL_iod_attribute_write(void *_attr, hid_t type_id, const void *buf, hid_t dxpl
 {
     H5VL_iod_attr_t *attr = (H5VL_iod_attr_t *)_attr;
     attr_io_in_t input;
-    H5P_genplist_t *plist;
+    H5P_genplist_t *plist = NULL;
     hg_bulk_t *bulk_handle = NULL;
     int *status = NULL;
     size_t size;
     H5VL_iod_io_info_t *info;
     uint32_t cs;
-    H5VL_iod_request_t **parent_req = NULL;
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Transaction ID")
+
     if(-1 == attr->remote_attr.space_id) {
         /* Synchronously wait on the request attached to the attribute */
         if(H5VL_iod_request_wait(attr->common.file, attr->common.request) < 0)
@@ -3604,34 +3666,26 @@ H5VL_iod_attribute_write(void *_attr, hid_t type_id, const void *buf, hid_t dxpl
     if(HG_SUCCESS != HG_Bulk_handle_create(buf, size, HG_BULK_READ_ONLY, bulk_handle))
         HGOTO_ERROR(H5E_ATTR, H5E_WRITEERROR, FAIL, "can't create Bulk Data Handle");
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests((H5VL_iod_object_t *)attr, (H5VL_iod_req_info_t *)tr, 
+                                    parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
     /* Fill input structure */
     input.coh = attr->common.file->remote_file.coh;
     input.iod_oh = attr->remote_attr.iod_oh;
     input.iod_id = attr->remote_attr.iod_id;
     input.bulk_handle = *bulk_handle;
     input.type_id = type_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != attr->common.request && attr->common.request->state != H5VL_IOD_COMPLETED) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &attr->common.request->axe_id;
-        attr->common.request->ref_count ++;
-        *parent_req = attr->common.request;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-        *parent_req = NULL;
-    }
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
     status = (int *)malloc(sizeof(int));
 
-    /* Get the dxpl plist structure */
-    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
-        HGOTO_ERROR(H5E_ATTR, H5E_BADATOM, FAIL, "can't find object for ID")
-
     /* setup info struct for I/O request 
        This is to manage the I/O operation once the wait is called. */
     if(NULL == (info = (H5VL_iod_io_info_t *)H5MM_malloc(sizeof(H5VL_iod_io_info_t))))
@@ -3641,8 +3695,8 @@ H5VL_iod_attribute_write(void *_attr, hid_t type_id, const void *buf, hid_t dxpl
 
     if(H5VL__iod_create_and_forward(H5VL_ATTR_WRITE_ID, HG_ATTR_WRITE, 
                                     (H5VL_iod_object_t *)attr, 0,
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, status, info, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)tr, &input, status, info, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship attribute write");
 
 done:
@@ -3671,48 +3725,66 @@ H5VL_iod_attribute_remove(void *_obj, H5VL_loc_params_t loc_params, const char *
     attr_op_in_t input;
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    H5VL_iod_request_t **parent_req = NULL;
-    char *new_name = NULL;   /* resolved path to where we need to start traversal at the server */
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
+    H5P_genplist_t *plist = NULL;
+    H5VL_iod_request_t **parent_reqs = NULL;
     int *status = NULL;
+    char *loc_name = NULL;
     herr_t ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    /* Retrieve the parent AXE id by traversing the path where the
-       attribute should be removed. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Transaction ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, ".", &iod_id, &iod_oh, 
-                                parent_req, &new_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
+
+    if(H5VL_OBJECT_BY_SELF == loc_params.type)
+        loc_name = strdup(".");
+    else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+        loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
     /* set the input structure for the HG encode routine */
     input.coh = obj->file->remote_file.coh;
     input.loc_id = iod_id;
     input.loc_oh = iod_oh;
-    input.path = new_name;
+    input.path = loc_name;
     input.attr_name = attr_name;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
     status = (int *)malloc(sizeof(int));
 
     if(H5VL__iod_create_and_forward(H5VL_ATTR_REMOVE_ID, HG_ATTR_REMOVE, 
                                     (H5VL_iod_object_t *)obj, 1, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, status, status, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)tr, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship attribute remove");
 
 done:
-    if(new_name) 
-        free(new_name);
+    if(loc_name) 
+        HDfree(loc_name);
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_attribute_remove() */
 
@@ -3737,11 +3809,26 @@ H5VL_iod_attribute_get(void *_obj, H5VL_attr_get_t get_type, hid_t dxpl_id,
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location of operation */
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    H5VL_iod_request_t **parent_req = NULL;
+    H5P_genplist_t *plist = NULL;
+    hid_t rcxt_id;
+    H5RC_t *rc;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
+    char *loc_name = NULL;
     herr_t  ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
+    /* get the context ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a READ CONTEXT ID")
+
     switch (get_type) {
         /* H5Aget_space */
         case H5VL_ATTR_GET_SPACE:
@@ -3833,40 +3920,41 @@ H5VL_iod_attribute_get(void *_obj, H5VL_attr_get_t get_type, hid_t dxpl_id,
                 H5VL_loc_params_t loc_params = va_arg (arguments, H5VL_loc_params_t);
                 char *attr_name = va_arg (arguments, char *);
                 htri_t *ret = va_arg (arguments, htri_t *);
-                char *new_name = NULL;
                 attr_op_in_t input;
 
-                /* Retrieve the parent AXE id by traversing the path where the
-                   attribute should be checked. */
-                if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+                /* allocate parent request array */
+                if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                            H5MM_malloc(sizeof(H5VL_iod_request_t *))))
                     HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(obj, loc_params, ".", &iod_id, &iod_oh, 
-                                            parent_req, &new_name, NULL) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+
+                /* retrieve parent requests */
+                if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)rc, parent_reqs, &num_parents) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+                /* retrieve IOD info of location object */
+                if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
+
+                if(H5VL_OBJECT_BY_SELF == loc_params.type)
+                    loc_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+                    loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
                 /* set the input structure for the HG encode routine */
                 input.coh = obj->file->remote_file.coh;
                 input.loc_id = iod_id;
                 input.loc_oh = iod_oh;
-                input.path = new_name;
                 input.attr_name = attr_name;
-                input.axe_info.axe_id = g_axe_id ++;
-                if(NULL != parent_req[0]) {
-                    input.axe_info.num_parents = 1;
-                    input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-                }
-                else {
-                    input.axe_info.num_parents = 0;
-                    input.axe_info.parent_axe_ids = NULL;
-                }
+                input.path = loc_name;
+                input.rcxt_num  = rc->c_version;
 
                 if(H5VL__iod_create_and_forward(H5VL_ATTR_EXISTS_ID, HG_ATTR_EXISTS, 
-                                                obj, 1, input.axe_info.num_parents, parent_req,
-                                                &input, ret, ret, req) < 0)
+                                                obj, 1, num_parents, parent_reqs,
+                                                (H5VL_iod_req_info_t *)rc, &input, ret, ret, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship attribute exists");
 
-                if(new_name) 
-                    free(new_name);
+                if(loc_name) 
+                    HDfree(loc_name);
                 break;
             }
         /* H5Aget_info */
@@ -3893,7 +3981,7 @@ H5VL_iod_attribute_get(void *_obj, H5VL_attr_get_t get_type, hid_t dxpl_id,
             }
         case H5VL_ATTR_GET_STORAGE_SIZE:
             {
-                hsize_t *ret = va_arg (arguments, hsize_t *);
+                //hsize_t *ret = va_arg (arguments, hsize_t *);
                 HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get attr storage size");
                 break;
             }
@@ -3920,13 +4008,12 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5VL_iod_attribute_close(void *_attr, hid_t dxpl_id, void **req)
+H5VL_iod_attribute_close(void *_attr, hid_t UNUSED dxpl_id, void **req)
 {
     H5VL_iod_attr_t *attr = (H5VL_iod_attr_t *)_attr;
     attr_close_in_t input;
     int *status;
-    size_t num_parents;
-    AXE_task_t *parent_axe_ids = NULL;
+    size_t num_parents = 0;
     H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;  /* Return value */
 
@@ -3948,48 +4035,35 @@ H5VL_iod_attribute_close(void *_attr, hid_t dxpl_id, void **req)
             HGOTO_ERROR(H5E_FILE,  H5E_CANTGET, FAIL, "can't wait on all object requests");
     }
 
-    if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)attr, &num_parents, NULL, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num AXE parents");
+    if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)attr, &num_parents, NULL) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num requests");
 
     if(num_parents) {
-        if(NULL == (parent_axe_ids = (AXE_task_t *)H5MM_malloc(sizeof(AXE_task_t) * num_parents)))
-            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent axe IDs");
         if(NULL == (parent_reqs = (H5VL_iod_request_t **)H5MM_malloc
                     (sizeof(H5VL_iod_request_t *) * num_parents)))
             HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent reqs");
-        if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)attr, &num_parents, 
-                                    parent_axe_ids, parent_reqs) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get AXE parents");
+
+        if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)attr, &num_parents, 
+                                     parent_reqs) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get parent requests");
     }
 
     status = (int *)malloc(sizeof(int));
 
     input.iod_oh = attr->remote_attr.iod_oh;
     input.iod_id = attr->remote_attr.iod_id;
-    input.axe_info.num_parents = num_parents;
-    input.axe_info.parent_axe_ids = parent_axe_ids;
-    input.axe_info.axe_id = g_axe_id ++;
 
 #if H5VL_IOD_DEBUG
-    {
-        size_t i;
-
-        printf("Attribute Close, axe id %llu, %d parents: ", 
-               input.axe_info.axe_id, num_parents);
-        for(i=0 ; i<num_parents ; i++)
-            printf("%llu ", parent_axe_ids[i]);
-        printf("\n");
-    }
+    printf("Attribute Close IOD ID %llu, axe id %llu\n", input.iod_id, g_axe_id);
 #endif
 
     if(H5VL__iod_create_and_forward(H5VL_ATTR_CLOSE_ID, HG_ATTR_CLOSE, 
                                     (H5VL_iod_object_t *)attr, 1,
                                     num_parents, parent_reqs,
-                                    &input, status, status, req) < 0)
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship attribute close");
 
 done:
-    parent_axe_ids = (AXE_task_t *)H5MM_xfree(parent_axe_ids);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_attribute_close() */
 
@@ -4012,30 +4086,43 @@ H5VL_iod_link_create(H5VL_link_create_type_t create_type, void *_obj, H5VL_loc_p
                      hid_t lcpl_id, hid_t lapl_id, hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location object */
-    H5VL_iod_object_t *cur_obj = NULL;
     link_create_in_t input;
     int *status;
-    H5P_genplist_t *plist;                      /* Property list pointer */
-    char *loc_name = NULL, *new_name = NULL;
+    H5P_genplist_t *plist = NULL;                      /* Property list pointer */
     char *link_value = NULL; /* Value of soft link */
-    size_t num_parents;
-    AXE_task_t *parent_axe_ids = NULL;
+    size_t num_parents = 0;
     H5VL_iod_request_t **parent_reqs = NULL;
-    H5VL_iod_request_t **parent_req = NULL;
-    H5VL_iod_request_t **target_req;
+    hid_t trans_id;
+    H5TR_t *tr;
     herr_t ret_value = SUCCEED;        /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Transaction ID")
+
     /* Get the plist structure */
     if(NULL == (plist = (H5P_genplist_t *)H5I_object(lcpl_id)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
 
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 3)))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
+
     switch (create_type) {
         case H5VL_LINK_CREATE_HARD:
             {
                 H5VL_iod_object_t *target_obj = NULL;
                 H5VL_loc_params_t target_params;
+                char *loc_name = NULL, *target_name = NULL;
 
                 if(H5P_get(plist, H5VL_LINK_TARGET, &target_obj) < 0)
                     HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for current location");
@@ -4047,27 +4134,41 @@ H5VL_iod_link_create(H5VL_link_create_type_t create_type, void *_obj, H5VL_loc_p
                     obj = target_obj;
                 }
 
+                /* retrieve parent requests */
+                if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+                /* retrieve IOD info of location object */
+                if(H5VL_iod_get_loc_info(obj, &input.loc_id, &input.loc_oh) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
+
+                if(H5VL_OBJECT_BY_SELF == loc_params.type)
+                    loc_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+                    loc_name = strdup(loc_params.loc_data.loc_by_name.name);
+
                 /* Retrieve the parent info by traversing the path where the
-                   link should be created from. */
-                if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                            parent_req, &loc_name, &cur_obj) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+                   link should be created. */
 
                 /* object is H5L_SAME_LOC */
                 if(NULL == target_obj && obj) {
                     target_obj = obj;
                 }
 
-                /* Retrieve the parent info by traversing the path where the
-                   link should be created. */
-                if(NULL == (target_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(target_obj, target_params, ".", 
-                                            &input.target_loc_id, &input.target_loc_oh, 
-                                            target_req, &new_name, NULL) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+                /* retrieve parent requests */
+                if(H5VL_iod_get_parent_requests(target_obj, NULL, 
+                                                &parent_reqs[num_parents], &num_parents) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+                /* retrieve IOD info of location object */
+                if(H5VL_iod_get_loc_info(target_obj, &input.target_loc_id, 
+                                         &input.target_loc_oh) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
+
+                if(H5VL_OBJECT_BY_SELF == target_params.type)
+                    target_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == target_params.type)
+                    target_name = strdup(target_params.loc_data.loc_by_name.name);
 
                 /* set the input structure for the HG encode routine */
                 input.create_type = H5VL_LINK_CREATE_HARD;
@@ -4076,18 +4177,23 @@ H5VL_iod_link_create(H5VL_link_create_type_t create_type, void *_obj, H5VL_loc_p
                 else
                     input.coh = target_obj->file->remote_file.coh;
 
+                input.target_name = target_name;
+                input.loc_name = loc_name;
                 input.lcpl_id = lcpl_id;
                 input.lapl_id = lapl_id;
-                input.loc_name = loc_name;
-                input.target_name = new_name;
-                input.axe_info.axe_id = g_axe_id ++;
                 link_value = strdup("\0");
                 input.link_value = link_value;
+
+                if(loc_name) 
+                    HDfree(loc_name);
+                if(target_name) 
+                    HDfree(target_name);
+
                 break;
             }
         case H5VL_LINK_CREATE_SOFT:
             {
-                char *target_name;
+                char *target_name = NULL, *loc_name = NULL;
                 H5VL_iod_object_t *target_obj = NULL;
                 H5VL_loc_params_t target_params;
 
@@ -4110,32 +4216,42 @@ H5VL_iod_link_create(H5VL_link_create_type_t create_type, void *_obj, H5VL_loc_p
 
                 /* Retrieve the parent info by traversing the path where the
                    link should be created from. */
-                if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                            parent_req, &loc_name, &cur_obj) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
 
-                /* Retrieve the parent info by traversing the path where the
-                   target link should be created. */
-                if(NULL == (target_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(target_obj, target_params, ".", 
-                                            &input.target_loc_id, &input.target_loc_oh, 
-                                            target_req, &new_name, NULL) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+                /* retrieve parent requests */
+                if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+                /* retrieve IOD info of location object */
+                if(H5VL_iod_get_loc_info(obj, &input.loc_id, &input.loc_oh) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
+
+                if(H5VL_OBJECT_BY_SELF == loc_params.type)
+                    loc_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+                    loc_name = strdup(loc_params.loc_data.loc_by_name.name);
+
+                /* retrieve parent requests */
+                if(H5VL_iod_get_parent_requests(target_obj, NULL, 
+                                                &parent_reqs[num_parents], &num_parents) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+                /* retrieve IOD info of location object */
+                if(H5VL_iod_get_loc_info(target_obj, &input.target_loc_id, 
+                                         &input.target_loc_oh) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
 
                 /* set the input structure for the HG encode routine */
                 input.create_type = H5VL_LINK_CREATE_SOFT;
                 input.coh = obj->file->remote_file.coh;
-
-                input.axe_info.axe_id = g_axe_id ++;
+                input.loc_name = loc_name;
+                input.target_name = target_name;
                 input.lcpl_id = lcpl_id;
                 input.lapl_id = lapl_id;
-                input.loc_name = loc_name;
-                input.target_name = new_name;
                 input.link_value = link_value;
 
+                if(loc_name) 
+                    HDfree(loc_name);
+
                 break;
             }
         /* MSC - not supported now */
@@ -4156,71 +4272,16 @@ H5VL_iod_link_create(H5VL_link_create_type_t create_type, void *_obj, H5VL_loc_p
             HGOTO_ERROR(H5E_LINK, H5E_CANTINIT, FAIL, "invalid link creation call")
     }
 
-    if(NULL == (parent_axe_ids = (AXE_task_t *)H5MM_malloc(sizeof(AXE_task_t) * 2)))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent axe IDs");
-    if(NULL == (parent_reqs = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent reqs");
-
-    if(NULL != parent_req[0] && NULL != target_req[0]) {
-        num_parents = 2;
-        parent_axe_ids[0] = parent_req[0]->axe_id;
-        parent_axe_ids[1] = target_req[0]->axe_id;
-        parent_reqs[0] = *parent_req;
-        parent_reqs[1] = *target_req;
-    }
-    else if (NULL != parent_req[0]) {
-        num_parents = 1;
-        parent_axe_ids[0] = parent_req[0]->axe_id;
-        parent_reqs[0] = *parent_req;
-    }
-    else if (NULL != target_req[0]) {
-        num_parents = 1;
-        parent_axe_ids[0] = target_req[0]->axe_id;
-        parent_reqs[0] = *target_req;
-    }
-    else {
-        num_parents = 0;
-    }
-
-    input.axe_info.num_parents = num_parents;
-    input.axe_info.parent_axe_ids = parent_axe_ids;
-
-#if H5VL_IOD_DEBUG
-    if(create_type == H5VL_LINK_CREATE_HARD)
-        printf("Hard Link Create axe %llu: %s ID %llu to %s ID %llu \n", 
-               input.axe_info.axe_id, loc_name, input.loc_id, 
-               new_name, input.target_loc_id);
-    else
-        printf("Soft Link Create axe %llu: %s ID %llu to %s ID %llu\n", 
-               input.axe_info.axe_id, loc_name, input.loc_id,
-               new_name, input.target_loc_id);
-
-    status = (herr_t *)malloc(sizeof(herr_t));
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
-    {
-        size_t i;
-        printf("Link Create Dependencies: ");
-        for(i=0 ; i<num_parents ; i++)
-            printf("%llu ", parent_axe_ids[i]);
-        printf("\n");
-    }
-#endif
-
-    if(H5VL__iod_create_and_forward(H5VL_LINK_CREATE_ID, HG_LINK_CREATE, cur_obj, 1,
-                                    num_parents, parent_reqs,
-                                    &input, status, status, req) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship link move");
+    if(H5VL__iod_create_and_forward(H5VL_LINK_CREATE_ID, HG_LINK_CREATE, 
+                                    obj, 1, num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)tr, &input, status, status, req) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship link create");
 
 done:
 
-    parent_req = (H5VL_iod_request_t **)H5MM_xfree(parent_req);
-    target_req = (H5VL_iod_request_t **)H5MM_xfree(target_req);
-    parent_axe_ids = (AXE_task_t *)H5MM_xfree(parent_axe_ids);
-
-    if(loc_name) 
-        HDfree(loc_name);
-    if(new_name) 
-        HDfree(new_name);
     if(link_value) 
         HDfree(link_value);
 
@@ -4256,31 +4317,54 @@ H5VL_iod_link_move(void *_src_obj, H5VL_loc_params_t loc_params1,
     H5VL_iod_object_t *cur_obj;
     link_move_in_t input;
     int *status;
-    char *src_name = NULL, *dst_name = NULL;
-    size_t num_parents;
-    AXE_task_t *parent_axe_ids = NULL;
     H5VL_iod_request_t **parent_reqs = NULL;
-    H5VL_iod_request_t **src_req;
-    H5VL_iod_request_t **dst_req;
+    H5P_genplist_t *plist = NULL;
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
+    char *src_name = NULL, *dst_name = NULL;
     herr_t ret_value = SUCCEED;        /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    /* Retrieve the parent information by traversing the path where the
-       link should be moved from. */
-        if(NULL == (src_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(src_obj, loc_params1, ".", &input.src_loc_id, &input.src_loc_oh, 
-                                src_req, &src_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
-
-    /* Retrieve the parent information by traversing the path where the
-       link should be moved to. */
-    if(NULL == (dst_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Transaction ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 3)))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(dst_obj, loc_params2, ".", &input.dst_loc_id, &input.dst_loc_oh, 
-                                dst_req, &dst_name, &cur_obj) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(src_obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(src_obj, &input.src_loc_id, &input.src_loc_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
+
+    if(H5VL_OBJECT_BY_SELF == loc_params1.type)
+        src_name = strdup(".");
+    else if(H5VL_OBJECT_BY_NAME == loc_params1.type)
+        src_name = strdup(loc_params1.loc_data.loc_by_name.name);
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(dst_obj, NULL, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(dst_obj, &input.dst_loc_id, &input.dst_loc_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
+
+    if(H5VL_OBJECT_BY_SELF == loc_params2.type)
+        dst_name = strdup(".");
+    else if(H5VL_OBJECT_BY_NAME == loc_params2.type)
+        dst_name = strdup(loc_params2.loc_data.loc_by_name.name);
 
     /* if the object, to be moved is open locally, then update its
        link information */
@@ -4305,65 +4389,25 @@ H5VL_iod_link_move(void *_src_obj, H5VL_loc_params_t loc_params1,
     /* set the input structure for the HG encode routine */
     input.coh = src_obj->file->remote_file.coh;
     input.copy_flag = copy_flag;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.lcpl_id = lcpl_id;
-    input.lapl_id = lapl_id;
     input.src_loc_name = src_name;
     input.dst_loc_name = dst_name;
-
-    if(NULL == (parent_axe_ids = (AXE_task_t *)H5MM_malloc(sizeof(AXE_task_t) * 2)))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent axe IDs");
-    if(NULL == (parent_reqs = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent reqs");
-
-    if(NULL != src_req[0] && NULL != dst_req[0]) {
-        num_parents = 2;
-        parent_axe_ids[0] = src_req[0]->axe_id;
-        parent_axe_ids[1] = dst_req[0]->axe_id;
-        parent_reqs[0] = *src_req;
-        parent_reqs[1] = *dst_req;
-    }
-    else if (NULL != src_req[0]) {
-        num_parents = 1;
-        parent_axe_ids[0] = src_req[0]->axe_id;
-        parent_reqs[0] = *src_req;
-    }
-    else if (NULL != dst_req[0]) {
-        num_parents = 1;
-        parent_axe_ids[0] = dst_req[0]->axe_id;
-        parent_reqs[0] = *dst_req;
-    }
-    else {
-        num_parents = 0;
-    }
-
-    input.axe_info.num_parents = num_parents;
-    input.axe_info.parent_axe_ids = parent_axe_ids;
-
-#if H5VL_IOD_DEBUG
-    {
-        size_t i;
-        printf("Link Move Dependencies: ");
-        for(i=0 ; i<num_parents ; i++)
-            printf("%llu ", parent_axe_ids[i]);
-        printf("\n");
-    }
-#endif
+    input.lcpl_id = lcpl_id;
+    input.lapl_id = lapl_id;
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
     status = (herr_t *)malloc(sizeof(herr_t));
 
     if(H5VL__iod_create_and_forward(H5VL_LINK_MOVE_ID, HG_LINK_MOVE, cur_obj, 1,
                                     num_parents, parent_reqs,
-                                    &input, status, status, req) < 0)
+                                    (H5VL_iod_req_info_t *)tr, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship link move");
 
 done:
-
-    parent_axe_ids = (AXE_task_t *)H5MM_xfree(parent_axe_ids);
-    src_req = (H5VL_iod_request_t **)H5MM_xfree(src_req);
-    dst_req = (H5VL_iod_request_t **)H5MM_xfree(dst_req);
-    if(src_name) free(src_name);
-    if(dst_name) free(dst_name);
+    if(src_name) 
+        free(src_name);
+    if(dst_name) 
+        free(dst_name);
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_link_move() */
@@ -4387,7 +4431,6 @@ static herr_t H5VL_iod_link_iterate(void *_obj, H5VL_loc_params_t loc_params, hb
                                     H5L_iterate_t op, void *op_data, hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj;
-    hid_t temp_id;
     herr_t ret_value = SUCCEED;  /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -4416,12 +4459,41 @@ H5VL_iod_link_get(void *_obj, H5VL_loc_params_t loc_params, H5VL_link_get_t get_
                   hid_t dxpl_id, void **req, va_list arguments)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj;
-    H5VL_iod_request_t **parent_req = NULL;
-    char *new_name = NULL;
+    H5VL_iod_request_t **parent_reqs = NULL;
+    size_t num_parents = 0;
+    hid_t rcxt_id;
+    H5RC_t *rc;
+    H5P_genplist_t *plist = NULL;
+    iod_obj_id_t iod_id;
+    iod_handle_t iod_oh;
+    char *loc_name = NULL;
     herr_t ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
+    /* get the context ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a READ CONTEXT ID");
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)rc, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
+
     switch (get_type) {
         /* H5Lexists */
         case H5VL_LINK_EXISTS:
@@ -4429,40 +4501,30 @@ H5VL_iod_link_get(void *_obj, H5VL_loc_params_t loc_params, H5VL_link_get_t get_
                 link_op_in_t input;
                 htri_t *ret    = va_arg (arguments, htri_t *);
 
-                /* Retrieve the parent info by traversing the path where the
-                   link should be checked. */
-                if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                            parent_req, &new_name, NULL) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+                if(H5VL_OBJECT_BY_SELF == loc_params.type)
+                    loc_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+                    loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
                 /* set the input structure for the HG encode routine */
                 input.coh = obj->file->remote_file.coh;
-                input.path = new_name;
-                input.axe_info.axe_id = g_axe_id ++;
-                if(NULL != parent_req[0]) {
-                    input.axe_info.num_parents = 1;
-                    input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-                }
-                else {
-                    input.axe_info.num_parents = 0;
-                    input.axe_info.parent_axe_ids = NULL;
-                }
+                input.loc_id = iod_id;
+                input.loc_oh = iod_oh;
+                input.rcxt_num  = rc->c_version;
+                input.path = loc_name;
 
 #if H5VL_IOD_DEBUG
-                printf("Link Exists axe %llu: %s ID %llu axe %llu\n", 
-                       input.axe_info.axe_id, new_name, input.loc_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+                printf("Link Exists axe %llu: %s ID %llu\n", 
+                       g_axe_id, loc_name, input.loc_id);
 #endif
 
                 if(H5VL__iod_create_and_forward(H5VL_LINK_EXISTS_ID, HG_LINK_EXISTS, 
-                                                obj, 0, input.axe_info.num_parents, parent_req,
-                                                &input, ret, ret, req) < 0)
+                                                obj, 0, num_parents, parent_reqs,
+                                                (H5VL_iod_req_info_t *)rc, &input, ret, ret, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship link exists");
 
-                if(new_name) 
-                    free(new_name);
-
+                if(loc_name) 
+                    HDfree(loc_name);
                 break;
             }
         /* H5Lget_info/H5Lget_info_by_idx */
@@ -4471,40 +4533,31 @@ H5VL_iod_link_get(void *_obj, H5VL_loc_params_t loc_params, H5VL_link_get_t get_
                 H5L_ff_info_t *linfo  = va_arg (arguments, H5L_ff_info_t *);
                 link_op_in_t input;
 
-                /* Retrieve the parent info by traversing the path where the
-                   link should be checked. */
-                if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                            parent_req, &new_name, NULL) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+                if(H5VL_OBJECT_BY_SELF == loc_params.type)
+                    loc_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+                    loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
                 /* set the input structure for the HG encode routine */
                 input.coh = obj->file->remote_file.coh;
-                input.path = new_name;
-                input.axe_info.axe_id = g_axe_id ++;
-                if(NULL != parent_req[0]) {
-                    input.axe_info.num_parents = 1;
-                    input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-                }
-                else {
-                    input.axe_info.num_parents = 0;
-                    input.axe_info.parent_axe_ids = NULL;
-                }
+                input.loc_id = iod_id;
+                input.loc_oh = iod_oh;
+                input.rcxt_num  = rc->c_version;
+                input.path = loc_name;
 
 #if H5VL_IOD_DEBUG
-                printf("Link get info axe %llu: %s ID %llu axe %llu\n", 
-                       input.axe_info.axe_id, new_name, input.loc_id, 
-                       ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+                printf("Link get info axe %llu: %s ID %llu\n", 
+                       g_axe_id, loc_name, input.loc_id);
 #endif
 
                 if(H5VL__iod_create_and_forward(H5VL_LINK_GET_INFO_ID, HG_LINK_GET_INFO, 
-                                                obj, 0, input.axe_info.num_parents, parent_req,
-                                                &input, linfo, linfo, req) < 0)
+                                                obj, 0, num_parents, parent_reqs,
+                                                (H5VL_iod_req_info_t *)rc, &input, linfo, linfo, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship link get_info");
 
-                if(new_name) 
-                    free(new_name);
+                if(loc_name) 
+                    HDfree(loc_name);
+
                 break;
             }
         /* H5Lget_val/H5Lget_val_by_idx */
@@ -4515,27 +4568,18 @@ H5VL_iod_link_get(void *_obj, H5VL_loc_params_t loc_params, H5VL_link_get_t get_
                 link_get_val_in_t input;
                 link_get_val_out_t *result;
 
-                /* Retrieve the parent info by traversing the path where the
-                   link should be checked. */
-                if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                            parent_req, &new_name, NULL) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+                if(H5VL_OBJECT_BY_SELF == loc_params.type)
+                    loc_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+                    loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
                 /* set the input structure for the HG encode routine */
                 input.coh = obj->file->remote_file.coh;
-                input.path = new_name;
                 input.length = size;
-                input.axe_info.axe_id = g_axe_id ++;
-                if(NULL != parent_req[0]) {
-                    input.axe_info.num_parents = 1;
-                    input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-                }
-                else {
-                    input.axe_info.num_parents = 0;
-                    input.axe_info.parent_axe_ids = NULL;
-                }
+                input.loc_id = iod_id;
+                input.loc_oh = iod_oh;
+                input.rcxt_num  = rc->c_version;
+                input.path = loc_name;
 
                 if(NULL == (result = (link_get_val_out_t *)malloc
                             (sizeof(link_get_val_out_t)))) {
@@ -4546,17 +4590,18 @@ H5VL_iod_link_get(void *_obj, H5VL_loc_params_t loc_params, H5VL_link_get_t get_
                 result->value.val = buf;
 
 #if H5VL_IOD_DEBUG
-                printf("Link get val axe %llu: %s ID %llu axe %llu\n", 
-                       input.axe_info.axe_id, new_name, input.loc_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+                printf("Link get val axe %llu: %s ID %llu\n", 
+                       g_axe_id, loc_name, input.loc_id);
 #endif
 
                 if(H5VL__iod_create_and_forward(H5VL_LINK_GET_VAL_ID, HG_LINK_GET_VAL, obj, 0,
-                                                input.axe_info.num_parents, parent_req,
-                                                &input, result, result, req) < 0)
+                                                num_parents, parent_reqs,
+                                                (H5VL_iod_req_info_t *)rc, &input, result, result, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship link get_val");
 
-                if(new_name) 
-                    free(new_name);
+                if(loc_name) 
+                    HDfree(loc_name);
+
                 break;
             }
         /* H5Lget_name_by_idx */
@@ -4593,49 +4638,66 @@ H5VL_iod_link_remove(void *_obj, H5VL_loc_params_t loc_params, hid_t dxpl_id, vo
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj;
     H5VL_iod_object_t *cur_obj;
     link_op_in_t input;
-    H5VL_iod_request_t **parent_req = NULL;
+    H5VL_iod_request_t **parent_reqs = NULL;
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
+    H5P_genplist_t *plist = NULL;
     int *status;
-    char *new_name = NULL;
+    char *loc_name = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    /* Retrieve the parent info by traversing the path where the
-       link should be removed. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Transaction ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                parent_req, &new_name, &cur_obj) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &input.loc_id, &input.loc_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
+
+    if(H5VL_OBJECT_BY_SELF == loc_params.type)
+        loc_name = strdup(".");
+    else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+        loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
     /* set the input structure for the HG encode routine */
     input.coh = obj->file->remote_file.coh;
-    input.path = new_name;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
+    input.path = loc_name;
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
 #if H5VL_IOD_DEBUG
-    printf("Link Remove axe %llu: %s ID %llu axe %llu\n", 
-           input.axe_info.axe_id, new_name, input.loc_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Link Remove axe %llu: %s ID %llu\n", 
+           g_axe_id, loc_name, input.loc_id);
 #endif
 
     status = (int *)malloc(sizeof(int));
 
     if(H5VL__iod_create_and_forward(H5VL_LINK_REMOVE_ID, HG_LINK_REMOVE, cur_obj, 1, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, status, status, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)tr, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship link remove");
 
 done:
-    if(new_name) 
-        free(new_name);
+    if(loc_name) 
+        HDfree(loc_name);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_link_remove() */
 
@@ -4658,12 +4720,26 @@ H5VL_iod_object_open(void *_obj, H5VL_loc_params_t loc_params,
                      H5I_type_t *opened_type, hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location object to open the group */
-    char *new_name = NULL;
-    H5VL_iod_request_t **parent_req = NULL;
+    H5P_genplist_t *plist = NULL;
+    hid_t rcxt_id;
+    H5RC_t *rc;
+    size_t num_parents = 0;
+    char *loc_name = NULL;
+    H5VL_iod_request_t **parent_reqs = NULL;
     void *ret_value;
 
     FUNC_ENTER_NOAPI_NOINIT
 
+    /* get the context ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, NULL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for trans_id");
+
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a READ CONTEXT ID")
+
     if(H5VL_OBJECT_BY_ADDR == loc_params.type) {
         switch(loc_params.loc_data.loc_by_addr.obj_type) {
         case H5O_TYPE_DATASET:
@@ -4686,9 +4762,7 @@ H5VL_iod_object_open(void *_obj, H5VL_loc_params_t loc_params,
                 input.loc_oh.cookie = IOD_OH_UNDEFINED;
                 input.name = ".";
                 input.dapl_id = H5P_DATASET_ACCESS_DEFAULT;
-                input.axe_info.axe_id = g_axe_id ++;
-                input.axe_info.num_parents = 0;
-                input.axe_info.parent_axe_ids = NULL;
+                input.rcxt_num  = rc->c_version;
 
                 dset->dapl_id = H5P_DATASET_ACCESS_DEFAULT;
 
@@ -4700,7 +4774,7 @@ H5VL_iod_object_open(void *_obj, H5VL_loc_params_t loc_params,
 
                 if(H5VL__iod_create_and_forward(H5VL_DSET_OPEN_ID, HG_DSET_OPEN, 
                                                 (H5VL_iod_object_t *)dset, 1, 0, NULL,
-                                                &input, &dset->remote_dset, dset, req) < 0)
+                                                (H5VL_iod_req_info_t *)rc, &input, &dset->remote_dset, dset, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship dataset create");
 
                 *opened_type = H5I_DATASET;
@@ -4727,9 +4801,7 @@ H5VL_iod_object_open(void *_obj, H5VL_loc_params_t loc_params,
                 input.loc_oh.cookie = IOD_OH_UNDEFINED;
                 input.name = ".";
                 input.tapl_id = H5P_DATATYPE_ACCESS_DEFAULT;
-                input.axe_info.axe_id = g_axe_id ++;
-                input.axe_info.num_parents = 0;
-                input.axe_info.parent_axe_ids = NULL;
+                input.rcxt_num  = rc->c_version;
 
                 dtype->tapl_id = H5P_DATATYPE_ACCESS_DEFAULT;
 
@@ -4741,7 +4813,7 @@ H5VL_iod_object_open(void *_obj, H5VL_loc_params_t loc_params,
 
                 if(H5VL__iod_create_and_forward(H5VL_DTYPE_OPEN_ID, HG_DTYPE_OPEN, 
                                                 (H5VL_iod_object_t *)dtype, 1, 0, NULL,
-                                                &input, &dtype->remote_dtype, dtype, req) < 0)
+                                                (H5VL_iod_req_info_t *)rc, &input, &dtype->remote_dtype, dtype, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship datatype open");
 
                 *opened_type = H5I_DATATYPE;
@@ -4767,9 +4839,7 @@ H5VL_iod_object_open(void *_obj, H5VL_loc_params_t loc_params,
                 input.loc_oh.cookie = IOD_OH_UNDEFINED;
                 input.name = ".";
                 input.gapl_id = H5P_GROUP_ACCESS_DEFAULT;
-                input.axe_info.axe_id = g_axe_id ++;
-                input.axe_info.num_parents = 0;
-                input.axe_info.parent_axe_ids = NULL;
+                input.rcxt_num  = rc->c_version;
 
                 grp->gapl_id = H5P_GROUP_ACCESS_DEFAULT;
 
@@ -4781,7 +4851,7 @@ H5VL_iod_object_open(void *_obj, H5VL_loc_params_t loc_params,
 
                 if(H5VL__iod_create_and_forward(H5VL_GROUP_OPEN_ID, HG_GROUP_OPEN, 
                                                 (H5VL_iod_object_t *)grp, 1, 0, NULL,
-                                                &input, &grp->remote_group, grp, req) < 0)
+                                                (H5VL_iod_req_info_t *)rc, &input, &grp->remote_group, grp, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship group open");
 
                 *opened_type = H5I_GROUP;
@@ -4809,9 +4879,7 @@ H5VL_iod_object_open(void *_obj, H5VL_loc_params_t loc_params,
                 input.loc_oh.cookie = IOD_OH_UNDEFINED;
                 input.name = ".";
                 input.mapl_id = H5P_GROUP_ACCESS_DEFAULT;
-                input.axe_info.axe_id = g_axe_id ++;
-                input.axe_info.num_parents = 0;
-                input.axe_info.parent_axe_ids = NULL;
+                input.rcxt_num  = rc->c_version;
 
                 map->mapl_id = H5P_GROUP_ACCESS_DEFAULT;
 
@@ -4823,7 +4891,7 @@ H5VL_iod_object_open(void *_obj, H5VL_loc_params_t loc_params,
 
                 if(H5VL__iod_create_and_forward(H5VL_MAP_OPEN_ID, HG_MAP_OPEN, 
                                                 (H5VL_iod_object_t *)map, 1, 0, NULL, 
-                                                &input, &map->remote_map, map, req) < 0)
+                                                (H5VL_iod_req_info_t *)rc, &input, &map->remote_map, map, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship map open");
 
                 *opened_type = H5I_MAP;
@@ -4839,34 +4907,39 @@ H5VL_iod_object_open(void *_obj, H5VL_loc_params_t loc_params,
         object_op_in_t input;
         H5VL_iod_remote_object_t remote_obj; /* generic remote object structure */
 
-        /* Retrieve the parent AXE id by traversing the path where the
-           object should be opened. */
-        if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-        if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                    parent_req, &new_name, NULL) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current working group");
+        /* allocate parent request array */
+        if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                    H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate parent req element");
+
+        /* retrieve parent requests */
+        if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)rc, parent_reqs, &num_parents) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to retrieve parent requests");
+
+        /* retrieve IOD info of location object */
+        if(H5VL_iod_get_loc_info(obj, &input.loc_id, &input.loc_oh) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current location group info");
+
+        if(H5VL_OBJECT_BY_SELF == loc_params.type)
+            loc_name = strdup(".");
+        else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+            loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
         /* set the input structure for the HG encode routine */
         input.coh = obj->file->remote_file.coh;
-        input.loc_name = new_name;
-        input.axe_info.axe_id = g_axe_id ++;
-        if(NULL != parent_req[0]) {
-            input.axe_info.num_parents = 1;
-            input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-        }
-        else {
-            input.axe_info.num_parents = 0;
-            input.axe_info.parent_axe_ids = NULL;
-        }
+        input.loc_name = loc_name;
+        input.rcxt_num  = rc->c_version;
 
         if(H5VL__iod_create_and_forward(H5VL_OBJECT_OPEN_ID, HG_OBJECT_OPEN, 
-                                        obj, 1, input.axe_info.num_parents, parent_req,
-                                        &input, &remote_obj, &remote_obj, req) < 0)
+                                        obj, 1, num_parents, parent_reqs,
+                                        (H5VL_iod_req_info_t *)rc, &input, &remote_obj, &remote_obj, req) < 0)
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship object open");
 
         *opened_type = remote_obj.obj_type;
 
+        if(loc_name) 
+            HDfree(loc_name);
+
         switch(remote_obj.obj_type) {
         case H5I_DATASET:
             {
@@ -5053,8 +5126,6 @@ H5VL_iod_object_open(void *_obj, H5VL_loc_params_t loc_params,
         }
     }
 done:
-    if(new_name) 
-        free(new_name);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_object_open */
 
@@ -5073,8 +5144,8 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t 
-H5VL_iod_object_copy(void *_src_obj, H5VL_loc_params_t loc_params1, const char *src_name, 
-                     void *_dst_obj, H5VL_loc_params_t loc_params2, const char *dst_name, 
+H5VL_iod_object_copy(void *_src_obj, H5VL_loc_params_t UNUSED loc_params1, const char *src_name, 
+                     void *_dst_obj, H5VL_loc_params_t UNUSED loc_params2, const char *dst_name, 
                      hid_t ocpypl_id, hid_t lcpl_id, hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *src_obj = (H5VL_iod_object_t *)_src_obj;
@@ -5082,96 +5153,62 @@ H5VL_iod_object_copy(void *_src_obj, H5VL_loc_params_t loc_params1, const char *
     H5VL_iod_object_t *cur_obj;
     object_copy_in_t input;
     int *status;
-    char *new_src_name = NULL, *new_dst_name = NULL;
-    size_t num_parents;
-    AXE_task_t *parent_axe_ids = NULL;
     H5VL_iod_request_t **parent_reqs = NULL;
-    H5VL_iod_request_t **src_req;
-    H5VL_iod_request_t **dst_req;
+    H5P_genplist_t *plist = NULL;
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
     herr_t ret_value = SUCCEED;        /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    /* Retrieve the parent information by traversing the path where the
-       link should be moved from. */
-        if(NULL == (src_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(src_obj, loc_params1, src_name, 
-                                &input.src_loc_id, &input.src_loc_oh, 
-                                src_req, &new_src_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
-
-    /* Retrieve the parent information by traversing the path where the
-       link should be moved to. */
-    if(NULL == (dst_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(dst_obj, loc_params2, dst_name, 
-                                &input.dst_loc_id, &input.dst_loc_oh, 
-                                dst_req, &new_dst_name, &cur_obj) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
 
-    /* set the input structure for the HG encode routine */
-    input.coh = src_obj->file->remote_file.coh;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.lcpl_id = lcpl_id;
-    input.ocpypl_id = ocpypl_id;
-    input.src_loc_name = new_src_name;
-    input.dst_loc_name = new_dst_name;
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Transaction ID")
 
-    if(NULL == (parent_axe_ids = (AXE_task_t *)H5MM_malloc(sizeof(AXE_task_t) * 2)))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent axe IDs");
-    if(NULL == (parent_reqs = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent reqs");
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 3)))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
-    if(NULL != src_req[0] && NULL != dst_req[0]) {
-        num_parents = 2;
-        parent_axe_ids[0] = src_req[0]->axe_id;
-        parent_axe_ids[1] = dst_req[0]->axe_id;
-        parent_reqs[0] = *src_req;
-        parent_reqs[1] = *dst_req;
-    }
-    else if (NULL != src_req[0]) {
-        num_parents = 1;
-        parent_axe_ids[0] = src_req[0]->axe_id;
-        parent_reqs[0] = *src_req;
-    }
-    else if (NULL != dst_req[0]) {
-        num_parents = 1;
-        parent_axe_ids[0] = dst_req[0]->axe_id;
-        parent_reqs[0] = *dst_req;
-    }
-    else {
-        num_parents = 0;
-    }
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(src_obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(src_obj, &input.src_loc_id, &input.src_loc_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
 
-    input.axe_info.num_parents = num_parents;
-    input.axe_info.parent_axe_ids = parent_axe_ids;
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(dst_obj, NULL, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(dst_obj, &input.dst_loc_id, &input.dst_loc_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
 
-#if H5VL_IOD_DEBUG
-    {
-        size_t i;
-        printf("Object Copy Dependencies: ");
-        for(i=0 ; i<num_parents ; i++)
-            printf("%llu ", parent_axe_ids[i]);
-        printf("\n");
-    }
-#endif
+    /* set the input structure for the HG encode routine */
+    input.coh = src_obj->file->remote_file.coh;
+    input.src_loc_name = src_name;
+    input.dst_loc_name = dst_name;
+    input.lcpl_id = lcpl_id;
+    input.ocpypl_id = ocpypl_id;
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
     status = (herr_t *)malloc(sizeof(herr_t));
 
     if(H5VL__iod_create_and_forward(H5VL_OBJECT_COPY_ID, HG_OBJECT_COPY, 
                                     (H5VL_iod_object_t *)cur_obj, 1,
                                     num_parents, parent_reqs,
-                                    &input, status, status, req) < 0)
+                                    (H5VL_iod_req_info_t *)tr, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship object copy");
 
 done:
-    parent_axe_ids = (AXE_task_t *)H5MM_xfree(parent_axe_ids);
-    src_req = (H5VL_iod_request_t **)H5MM_xfree(src_req);
-    dst_req = (H5VL_iod_request_t **)H5MM_xfree(dst_req);
-    if(new_src_name) free(new_src_name);
-    if(new_dst_name) free(new_dst_name);
-
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_object_copy() */
 
@@ -5194,7 +5231,6 @@ static herr_t H5VL_iod_object_visit(void *_obj, H5VL_loc_params_t loc_params, H5
                                     hid_t dxpl_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj;
-    hid_t temp_id;
     herr_t ret_value = SUCCEED;  /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -5223,58 +5259,80 @@ H5VL_iod_object_misc(void *_obj, H5VL_loc_params_t loc_params, H5VL_object_misc_
                      hid_t dxpl_id, void **req, va_list arguments)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj;
+    iod_obj_id_t iod_id;
+    iod_handle_t iod_oh;
     int *status = NULL;
-    H5VL_iod_request_t **parent_req = NULL;
+    size_t num_parents = 0;
+    hid_t trans_id;
+    H5TR_t *tr;
+    H5P_genplist_t *plist = NULL;
+    H5VL_iod_request_t **parent_reqs = NULL;
+    char *loc_name = NULL;
     herr_t ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
+    /* get the transaction ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_TRANS_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Transaction ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
+
     switch (misc_type) {
         /* H5Arename/rename_by_name */
         case H5VL_ATTR_RENAME:
             {
                 const char    *old_name  = va_arg (arguments, const char *);
                 const char    *new_name  = va_arg (arguments, const char *);
-                char *loc_name = NULL;
                 attr_rename_in_t input;
 
-                /* Retrieve the parent AXE id by traversing the path where the
-                   attribute is located. */
-                if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                            parent_req, &loc_name, NULL) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+                if(H5VL_OBJECT_BY_SELF == loc_params.type)
+                    loc_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+                    loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
                 /* set the input structure for the HG encode routine */
                 input.coh = obj->file->remote_file.coh;
-                input.path = loc_name;
                 input.old_attr_name = old_name;
                 input.new_attr_name = new_name;
-                input.axe_info.axe_id = g_axe_id ++;
-                if(NULL != parent_req[0]) {
-                    input.axe_info.num_parents = 1;
-                    input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-                }
-                else {
-                    input.axe_info.num_parents = 0;
-                    input.axe_info.parent_axe_ids = NULL;
-                }
+                input.loc_id = iod_id;
+                input.loc_oh = iod_oh;
+                input.path = loc_name;
+                input.trans_num = tr->trans_num;
+                input.rcxt_num  = tr->c_version;
 
 #if H5VL_IOD_DEBUG
-                printf("Attribute Rename %s to %s LOC ID %llu, axe id %llu, parent %llu\n", 
-                       old_name, new_name, input.loc_id, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+                printf("Attribute Rename %s to %s LOC ID %llu, axe id %llu\n", 
+                       old_name, new_name, input.loc_id, g_axe_id);
 #endif
 
                 status = (herr_t *)malloc(sizeof(herr_t));
 
                 if(H5VL__iod_create_and_forward(H5VL_ATTR_RENAME_ID, HG_ATTR_RENAME, 
-                                                obj, 1, input.axe_info.num_parents, parent_req,
-                                                &input, status, status, req) < 0)
+                                                obj, 1, num_parents, parent_reqs,
+                                                (H5VL_iod_req_info_t *)tr, &input, status, status, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship attribute rename");
 
                 if(loc_name) 
-                    free(loc_name);
+                    HDfree(loc_name);
+
                 break;
             }
         /* H5Oset_comment */
@@ -5282,35 +5340,26 @@ H5VL_iod_object_misc(void *_obj, H5VL_loc_params_t loc_params, H5VL_object_misc_
             {
                 const char    *comment  = va_arg (arguments, char *);
                 object_set_comment_in_t input;
-                char *loc_name = NULL;
 
-                /* Retrieve the parent AXE id by traversing the path where the
-                   object is located. */
-                if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                           parent_req, &loc_name, NULL) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+                if(H5VL_OBJECT_BY_SELF == loc_params.type)
+                    loc_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+                    loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
                 /* set the input structure for the HG encode routine */
                 input.coh = obj->file->remote_file.coh;
-                input.path = loc_name;
                 input.comment = comment;
-                input.axe_info.axe_id = g_axe_id ++;
-                if(NULL != parent_req[0]) {
-                    input.axe_info.num_parents = 1;
-                    input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-                }
-                else {
-                    input.axe_info.num_parents = 0;
-                    input.axe_info.parent_axe_ids = NULL;
-                }
+                input.loc_id = iod_id;
+                input.loc_oh = iod_oh;
+                input.path = loc_name;
+                input.trans_num = tr->trans_num;
+                input.rcxt_num  = tr->c_version;
 
                 status = (herr_t *)malloc(sizeof(herr_t));
 
                 if(H5VL__iod_create_and_forward(H5VL_OBJECT_SET_COMMENT_ID, HG_OBJECT_SET_COMMENT, 
-                                                obj, 0, input.axe_info.num_parents, parent_req,
-                                                &input, status, status, req) < 0)
+                                                obj, 0, num_parents, parent_reqs,
+                                                (H5VL_iod_req_info_t *)tr, &input, status, status, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship object set_comment");
 
                 /* store the comment locally if the object is open */
@@ -5318,16 +5367,17 @@ H5VL_iod_object_misc(void *_obj, H5VL_loc_params_t loc_params, H5VL_object_misc_
                     obj->comment = HDstrdup(comment);
 
                 if(loc_name) 
-                    free(loc_name);
+                    HDfree(loc_name);
                 break;
             }
         /* H5Oincr_refcount / H5Odecr_refcount */
         case H5VL_OBJECT_CHANGE_REF_COUNT:
             {
-                int update_ref  = va_arg (arguments, int);
+                //int update_ref  = va_arg (arguments, int);
             }
         case H5VL_REF_CREATE:
             {
+                /*
                 void        *ref      = va_arg (arguments, void *);
                 const char  *name     = va_arg (arguments, char *);
                 H5R_type_t  ref_type  = va_arg (arguments, H5R_type_t);
@@ -5338,6 +5388,7 @@ H5VL_iod_object_misc(void *_obj, H5VL_loc_params_t loc_params, H5VL_object_misc_
                     ref_size = sizeof(hdset_reg_ref_t);
                 else if (ref_type == H5R_OBJECT)
                     ref_size = sizeof(hobj_ref_t);
+                */
             }
         default:
             HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't recognize this operation type")
@@ -5366,13 +5417,41 @@ H5VL_iod_object_get(void *_obj, H5VL_loc_params_t loc_params, H5VL_object_get_t
                     hid_t dxpl_id, void **req, va_list arguments)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj;
-    int *status;
-    char *new_name = NULL;
-    H5VL_iod_request_t **parent_req = NULL;
+    size_t num_parents = 0;
+    hid_t rcxt_id;
+    H5RC_t *rc;
+    H5P_genplist_t *plist = NULL;
+    iod_obj_id_t iod_id;
+    iod_handle_t iod_oh;
+    H5VL_iod_request_t **parent_reqs = NULL;
+    char *loc_name = NULL;
     herr_t ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
+    /* get the context ID */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+    if(H5P_get(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a READ CONTEXT ID");
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)rc, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current location group info");
+
     switch (get_type) {
         /* H5Oexists_by_name */
         case H5VL_OBJECT_EXISTS:
@@ -5380,39 +5459,30 @@ H5VL_iod_object_get(void *_obj, H5VL_loc_params_t loc_params, H5VL_object_get_t
                 htri_t	  *ret = va_arg (arguments, htri_t *);
                 object_op_in_t input;
 
-                /* Retrieve the parent info by traversing the path where the
-                   object should be checked. */
-                if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                            parent_req, &new_name, NULL) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+                if(H5VL_OBJECT_BY_SELF == loc_params.type)
+                    loc_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+                    loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
                 /* set the input structure for the HG encode routine */
                 input.coh = obj->file->remote_file.coh;
-                input.axe_info.axe_id = g_axe_id ++;
-                input.loc_name = new_name;
-                if(NULL != parent_req[0]) {
-                    input.axe_info.num_parents = 1;
-                    input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-                }
-                else {
-                    input.axe_info.num_parents = 0;
-                    input.axe_info.parent_axe_ids = NULL;
-                }
+                input.loc_id = iod_id;
+                input.loc_oh = iod_oh;
+                input.rcxt_num  = rc->c_version;
+                input.loc_name = loc_name;
 
 #if H5VL_IOD_DEBUG
-                printf("Object Exists axe %llu: %s ID %llu axe %llu\n", 
-                       input.axe_info.axe_id, new_name, input.loc_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+                printf("Object Exists axe %llu: %s ID %llu\n", 
+                       g_axe_id, input.loc_name, input.loc_id);
 #endif
 
                 if(H5VL__iod_create_and_forward(H5VL_OBJECT_EXISTS_ID, HG_OBJECT_EXISTS, 
-                                                obj, 0, input.axe_info.num_parents, parent_req,
-                                                &input, ret, ret, req) < 0)
+                                                obj, 0, num_parents, parent_reqs,
+                                                (H5VL_iod_req_info_t *)rc, &input, ret, ret, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship object exists");
 
-                if(new_name) 
-                    free(new_name);
+                if(loc_name) 
+                    HDfree(loc_name);
                 break;
             }
         /* H5Oget_comment / H5Oget_comment_by_name */
@@ -5442,30 +5512,21 @@ H5VL_iod_object_get(void *_obj, H5VL_loc_params_t loc_params, H5VL_object_get_t
 
                 /* Otherwise Go to the server */
 
-                /* Retrieve the parent info by traversing the path where the
-                   object should be checked. */
-                if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                            parent_req, &new_name, NULL) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+                if(H5VL_OBJECT_BY_SELF == loc_params.type)
+                    loc_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+                    loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
                 /* set the input structure for the HG encode routine */
                 input.coh = obj->file->remote_file.coh;
-                input.path = new_name;
+                input.loc_id = iod_id;
+                input.loc_oh = iod_oh;
+                input.rcxt_num  = rc->c_version;
+                input.path = loc_name;
                 if(comment)
                     input.length = size;
                 else
                     input.length = 0;
-                input.axe_info.axe_id = g_axe_id ++;
-                if(NULL != parent_req[0]) {
-                    input.axe_info.num_parents = 1;
-                    input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-                }
-                else {
-                    input.axe_info.num_parents = 0;
-                    input.axe_info.parent_axe_ids = NULL;
-                }
 
                 if(NULL == (result = (object_get_comment_out_t *)malloc
                             (sizeof(object_get_comment_out_t)))) {
@@ -5477,17 +5538,17 @@ H5VL_iod_object_get(void *_obj, H5VL_loc_params_t loc_params, H5VL_object_get_t
                 result->name.value = comment;
 
 #if H5VL_IOD_DEBUG
-                printf("Object Get Comment axe %llu: %s ID %llu axe %llu\n", 
-                       input.axe_info.axe_id, new_name, input.loc_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+                printf("Object Get Comment axe %llu: %s ID %llu\n", 
+                       g_axe_id, loc_name, input.loc_id);
 #endif
 
                 if(H5VL__iod_create_and_forward(H5VL_OBJECT_GET_COMMENT_ID, HG_OBJECT_GET_COMMENT, 
-                                                obj, 0, input.axe_info.num_parents, parent_req,
-                                                &input, result, result, req) < 0)
+                                                obj, 0, num_parents, parent_reqs,
+                                                (H5VL_iod_req_info_t *)rc, &input, result, result, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship object get_comment");
 
-                if(new_name) 
-                    free(new_name);
+                if(loc_name) 
+                    HDfree(loc_name);
                 break;
             }
         /* H5Oget_info / H5Oget_info_by_name / H5Oget_info_by_idx */
@@ -5496,64 +5557,55 @@ H5VL_iod_object_get(void *_obj, H5VL_loc_params_t loc_params, H5VL_object_get_t
                 H5O_ff_info_t  *oinfo = va_arg (arguments, H5O_ff_info_t *);
                 object_op_in_t input;
 
-                /* Retrieve the parent info by traversing the path where the
-                   object should be checked. */
-                if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-                    HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-                if(H5VL_iod_get_parent_info(obj, loc_params, ".", &input.loc_id, &input.loc_oh, 
-                                            parent_req, &new_name, NULL) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to resolve current working group");
+                if(H5VL_OBJECT_BY_SELF == loc_params.type)
+                    loc_name = strdup(".");
+                else if(H5VL_OBJECT_BY_NAME == loc_params.type)
+                    loc_name = strdup(loc_params.loc_data.loc_by_name.name);
 
                 /* set the input structure for the HG encode routine */
                 input.coh = obj->file->remote_file.coh;
-                input.loc_name = new_name;
-                input.axe_info.axe_id = g_axe_id ++;
-                if(NULL != parent_req[0]) {
-                    input.axe_info.num_parents = 1;
-                    input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-                }
-                else {
-                    input.axe_info.num_parents = 0;
-                    input.axe_info.parent_axe_ids = NULL;
-                }
+                input.loc_id = iod_id;
+                input.loc_oh = iod_oh;
+                input.rcxt_num  = rc->c_version;
+                input.loc_name = loc_name;
 
 #if H5VL_IOD_DEBUG
-                printf("Object get_info axe %llu: %s ID %llu axe %llu\n", 
-                       input.axe_info.axe_id, new_name, input.loc_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+                printf("Object get_info axe %llu: %s ID %llu\n", 
+                       g_axe_id, input.loc_name, input.loc_id);
 #endif
 
                 if(H5VL__iod_create_and_forward(H5VL_OBJECT_GET_INFO_ID, HG_OBJECT_GET_INFO, 
-                                                obj, 0, input.axe_info.num_parents, parent_req,
-                                                &input, oinfo, oinfo, req) < 0)
+                                                obj, 0, num_parents, parent_reqs,
+                                                (H5VL_iod_req_info_t *)rc, &input, oinfo, oinfo, req) < 0)
                     HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship object get_info");
 
-                if(new_name) 
-                    free(new_name);
+                if(loc_name) 
+                    HDfree(loc_name);
                 break;
             }
         /* H5Rget_region */
         case H5VL_REF_GET_REGION:
             {
-                hid_t       *ret     =  va_arg (arguments, hid_t *);
-                H5R_type_t  ref_type =  va_arg (arguments, H5R_type_t);
-                void        *ref     =  va_arg (arguments, void *);
-                H5S_t       *space = NULL;    /* Dataspace object */
+                //hid_t       *ret     =  va_arg (arguments, hid_t *);
+                //H5R_type_t  ref_type =  va_arg (arguments, H5R_type_t);
+                //void        *ref     =  va_arg (arguments, void *);
+                //H5S_t       *space = NULL;    /* Dataspace object */
             }
         /* H5Rget_obj_type2 */
         case H5VL_REF_GET_TYPE:
             {
-                H5O_type_t  *obj_type  =  va_arg (arguments, H5O_type_t *);
-                H5R_type_t  ref_type   =  va_arg (arguments, H5R_type_t);
-                const void  *ref       =  va_arg (arguments, const void *);
+                //H5O_type_t  *obj_type  =  va_arg (arguments, H5O_type_t *);
+                //H5R_type_t  ref_type   =  va_arg (arguments, H5R_type_t);
+                //const void  *ref       =  va_arg (arguments, const void *);
             }
         /* H5Rget_name */
         case H5VL_REF_GET_NAME:
             {
-                ssize_t     *ret       = va_arg (arguments, ssize_t *);
-                char        *name      = va_arg (arguments, char *);
-                size_t      size       = va_arg (arguments, size_t);
-                H5R_type_t  ref_type   = va_arg (arguments, H5R_type_t);
-                void        *ref       = va_arg (arguments, void *);
+                //ssize_t     *ret       = va_arg (arguments, ssize_t *);
+                //char        *name      = va_arg (arguments, char *);
+                //size_t      size       = va_arg (arguments, size_t);
+                //H5R_type_t  ref_type   = va_arg (arguments, H5R_type_t);
+                //void        *ref       = va_arg (arguments, void *);
             }
         default:
             HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't get this type of information from object")
@@ -5563,7 +5615,7 @@ done:
 } /* end H5VL_iod_object_get() */
 
 void *
-H5VL_iod_map_create(void *_obj, H5VL_loc_params_t loc_params, const char *name, 
+H5VL_iod_map_create(void *_obj, H5VL_loc_params_t UNUSED loc_params, const char *name, 
                     hid_t keytype, hid_t valtype, hid_t lcpl_id, hid_t mcpl_id, 
                     hid_t mapl_id, hid_t trans_id, void **req)
 {
@@ -5572,19 +5624,29 @@ H5VL_iod_map_create(void *_obj, H5VL_loc_params_t loc_params, const char *name,
     map_create_in_t input;
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    H5VL_iod_request_t **parent_req = NULL;
-    char *new_name = NULL; /* resolved path to where we need to start traversal at the server */
+    H5VL_iod_request_t **parent_reqs = NULL;
+    size_t num_parents = 0;
+    H5TR_t *tr;
     void *ret_value = NULL;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    /* Retrieve the parent AXE id by traversing the path where the
-       map should be created. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, name, &iod_id, &iod_oh, 
-                                parent_req, &new_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current working group");
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a Transaction ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current location group info");
 
     /* allocate the map object that is returned to the user */
     if(NULL == (map = H5FL_CALLOC(H5VL_iod_map_t)))
@@ -5607,25 +5669,18 @@ H5VL_iod_map_create(void *_obj, H5VL_loc_params_t loc_params, const char *name,
     input.coh = obj->file->remote_file.coh;
     input.loc_id = iod_id;
     input.loc_oh = iod_oh;
-    input.name = new_name;
+    input.name = name;
     input.keytype_id = keytype;
     input.valtype_id = valtype;
     input.mcpl_id = mcpl_id;
     input.mapl_id = mapl_id;
     input.lcpl_id = lcpl_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
 #if H5VL_IOD_DEBUG
-    printf("Map Create %s, IOD ID %llu, axe id %llu, parent %llu\n", 
-           new_name, input.map_id, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Map Create %s, IOD ID %llu, axe id %llu\n", 
+           name, input.map_id, g_axe_id);
 #endif
 
     /* setup the local map struct */
@@ -5658,40 +5713,48 @@ H5VL_iod_map_create(void *_obj, H5VL_loc_params_t loc_params, const char *name,
 
     if(H5VL__iod_create_and_forward(H5VL_MAP_CREATE_ID, HG_MAP_CREATE, 
                                     (H5VL_iod_object_t *)map, 1, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, &map->remote_map, map, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)tr, &input, &map->remote_map, map, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship map create");
 
     ret_value = (void *)map;
 
 done:
-    if(new_name) 
-        free(new_name);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_map_create() */
 
 void *
-H5VL_iod_map_open(void *_obj, H5VL_loc_params_t loc_params, const char *name, hid_t mapl_id, 
-                  hid_t rcxt_id, void **req)
+H5VL_iod_map_open(void *_obj, H5VL_loc_params_t UNUSED loc_params, const char *name, 
+                  hid_t mapl_id, hid_t rcxt_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location object to create the group */
     H5VL_iod_map_t *map = NULL; /* the map object that is created and passed to the user */
     map_open_in_t input;
     iod_obj_id_t iod_id;
     iod_handle_t iod_oh;
-    H5VL_iod_request_t **parent_req = NULL;
-    char *new_name = NULL; /* resolved path to where we need to start traversal at the server */
+    H5VL_iod_request_t **parent_reqs = NULL;
+    H5RC_t *rc;
+    size_t num_parents = 0;
     void *ret_value = NULL;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    /* Retrieve the parent AXE id by traversing the path where the
-       map should be created. */
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
-    if(H5VL_iod_get_parent_info(obj, loc_params, name, &iod_id, &iod_oh, 
-                                parent_req, &new_name, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current working group");
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a READ CONTEXT ID")
+
+    /* allocate parent request array */
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't allocate parent req element");
+
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(obj, (H5VL_iod_req_info_t *)rc, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to retrieve parent requests");
+
+    /* retrieve IOD info of location object */
+    if(H5VL_iod_get_loc_info(obj, &iod_id, &iod_oh) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "Failed to resolve current location group info");
 
     /* allocate the map object that is returned to the user */
     if(NULL == (map = H5FL_CALLOC(H5VL_iod_map_t)))
@@ -5706,21 +5769,13 @@ H5VL_iod_map_open(void *_obj, H5VL_loc_params_t loc_params, const char *name, hi
     input.coh = obj->file->remote_file.coh;
     input.loc_id = iod_id;
     input.loc_oh = iod_oh;
-    input.name = new_name;
+    input.name = name;
     input.mapl_id = mapl_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != parent_req[0]) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &parent_req[0]->axe_id;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-    }
+    input.rcxt_num  = rc->c_version;
 
 #if H5VL_IOD_DEBUG
-    printf("Map Open %s LOC ID %llu, axe id %llu, parent %llu, name len %zu\n", 
-           new_name, input.loc_id, input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0), strlen(input.name));
+    printf("Map Open %s LOC ID %llu, axe id %llu\n", 
+           name, input.loc_id, g_axe_id);
 #endif
 
     /* setup the local map struct */
@@ -5746,14 +5801,13 @@ H5VL_iod_map_open(void *_obj, H5VL_loc_params_t loc_params, const char *name, hi
     map->common.file->nopen_objs ++;
 
     if(H5VL__iod_create_and_forward(H5VL_MAP_OPEN_ID, HG_MAP_OPEN, (H5VL_iod_object_t *)map, 1, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, &map->remote_map, map, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)rc, &input, &map->remote_map, map, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship map open");
 
     ret_value = (void *)map;
 
 done:
-    if(new_name) free(new_name);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_map_open() */
 
@@ -5766,7 +5820,9 @@ H5VL_iod_map_set(void *_map, hid_t key_mem_type_id, const void *key,
     map_set_in_t input;
     size_t key_size, val_size;
     int *status = NULL;
-    H5VL_iod_request_t **parent_req = NULL;
+    size_t num_parents = 0;
+    H5TR_t *tr;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -5795,9 +5851,19 @@ H5VL_iod_map_set(void *_map, hid_t key_mem_type_id, const void *key,
         val_size = H5T_GET_SIZE(dt);
     }
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Transaction ID")
+
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests((H5VL_iod_object_t *)map, (H5VL_iod_req_info_t *)tr, 
+                                    parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
     /* Fill input structure */
     input.coh = map->common.file->remote_file.coh;
     input.iod_oh = map->remote_map.iod_oh;
@@ -5811,30 +5877,19 @@ H5VL_iod_map_set(void *_map, hid_t key_mem_type_id, const void *key,
     input.val_memtype_id = val_mem_type_id;
     input.val.buf_size = val_size;
     input.val.buf = value;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != map->common.request && map->common.request->state != H5VL_IOD_COMPLETED) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &map->common.request->axe_id;
-        map->common.request->ref_count ++;
-        *parent_req = map->common.request;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-        *parent_req = NULL;
-    }
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
     status = (int *)malloc(sizeof(int));
 
 #if H5VL_IOD_DEBUG
-    printf("MAP set, axe id %llu, parent %llu\n", 
-           input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("MAP set, axe id %llu\n", g_axe_id);
 #endif
 
     if(H5VL__iod_create_and_forward(H5VL_MAP_SET_ID, HG_MAP_SET, 
                                     (H5VL_iod_object_t *)map, 0,
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, status, status, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)tr, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship map set");
 
 done:
@@ -5850,7 +5905,9 @@ H5VL_iod_map_get(void *_map, hid_t key_mem_type_id, const void *key,
     map_get_in_t input;
     map_get_out_t *output;
     size_t key_size, val_size;
-    H5VL_iod_request_t **parent_req = NULL;
+    H5RC_t *rc;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -5879,9 +5936,19 @@ H5VL_iod_map_get(void *_map, hid_t key_mem_type_id, const void *key,
         val_size = H5T_GET_SIZE(dt);
     }
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a READ CONTEXT ID")
+
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests((H5VL_iod_object_t *)map, (H5VL_iod_req_info_t *)rc, 
+                                    parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
     /* Fill input structure */
     input.coh = map->common.file->remote_file.coh;
     input.iod_oh = map->remote_map.iod_oh;
@@ -5893,22 +5960,10 @@ H5VL_iod_map_get(void *_map, hid_t key_mem_type_id, const void *key,
     input.key.buf_size = key_size;
     input.key.buf = key;
     input.val_memtype_id = val_mem_type_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != map->common.request && map->common.request->state != H5VL_IOD_COMPLETED) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &map->common.request->axe_id;
-        map->common.request->ref_count ++;
-        *parent_req = map->common.request;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-        *parent_req = NULL;
-    }
+    input.rcxt_num  = rc->c_version;
 
 #if H5VL_IOD_DEBUG
-    printf("MAP Get, axe id %llu, parent %llu\n", 
-           input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("MAP Get, axe id %llu\n", g_axe_id);
 #endif
 
     if(NULL == (output = (map_get_out_t *)H5MM_calloc(sizeof(map_get_out_t))))
@@ -5919,8 +5974,8 @@ H5VL_iod_map_get(void *_map, hid_t key_mem_type_id, const void *key,
 
     if(H5VL__iod_create_and_forward(H5VL_MAP_GET_ID, HG_MAP_GET, 
                                     (H5VL_iod_object_t *)map, 0,
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, output, output, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)rc, &input, output, output, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship map get");
 
 done:
@@ -5929,7 +5984,7 @@ done:
 
 herr_t 
 H5VL_iod_map_get_types(void *_map, hid_t *key_type_id, hid_t *val_type_id, 
-                       hid_t rcxt_id, void **req)
+                       hid_t UNUSED rcxt_id, void UNUSED **req)
 {
     H5VL_iod_map_t *map = (H5VL_iod_map_t *)_map;
     herr_t ret_value = SUCCEED;
@@ -5960,40 +6015,40 @@ H5VL_iod_map_get_count(void *_map, hsize_t *count, hid_t rcxt_id, void **req)
 {
     H5VL_iod_map_t *map = (H5VL_iod_map_t *)_map;
     map_get_count_in_t input;
-    H5VL_iod_request_t **parent_req = NULL;
+    H5RC_t *rc;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a READ CONTEXT ID")
+
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests((H5VL_iod_object_t *)map, (H5VL_iod_req_info_t *)rc, 
+                                    parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
     /* Fill input structure */
     input.coh = map->common.file->remote_file.coh;
     input.iod_oh = map->remote_map.iod_oh;
     input.iod_id = map->remote_map.iod_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != map->common.request && map->common.request->state != H5VL_IOD_COMPLETED) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &map->common.request->axe_id;
-        map->common.request->ref_count ++;
-        *parent_req = map->common.request;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-        *parent_req = NULL;
-    }
+    input.rcxt_num  = rc->c_version;
 
 #if H5VL_IOD_DEBUG
-    printf("MAP Get count, axe id %llu, parent %llu\n", 
-           input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("MAP Get count, axe id %llu\n", g_axe_id);
 #endif
 
     if(H5VL__iod_create_and_forward(H5VL_MAP_GET_COUNT_ID, HG_MAP_GET_COUNT, 
                                     (H5VL_iod_object_t *)map, 0,
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, count, count, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)rc, &input, count, count, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship map get_count");
 
 done:
@@ -6007,7 +6062,9 @@ H5VL_iod_map_exists(void *_map, hid_t key_mem_type_id, const void *key,
     H5VL_iod_map_t *map = (H5VL_iod_map_t *)_map;
     map_op_in_t input;
     size_t key_size;
-    H5VL_iod_request_t **parent_req = NULL;
+    H5RC_t *rc;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -6021,9 +6078,19 @@ H5VL_iod_map_exists(void *_map, hid_t key_mem_type_id, const void *key,
         key_size = H5T_GET_SIZE(dt);
     }
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    /* get the RC object */
+    if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a READ CONTEXT ID")
+
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests((H5VL_iod_object_t *)map, (H5VL_iod_req_info_t *)rc, 
+                                    parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
     /* Fill input structure */
     input.coh = map->common.file->remote_file.coh;
     input.iod_oh = map->remote_map.iod_oh;
@@ -6032,28 +6099,16 @@ H5VL_iod_map_exists(void *_map, hid_t key_mem_type_id, const void *key,
     input.key_memtype_id = key_mem_type_id;
     input.key.buf_size = key_size;
     input.key.buf = key;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != map->common.request && map->common.request->state != H5VL_IOD_COMPLETED) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &map->common.request->axe_id;
-        map->common.request->ref_count ++;
-        *parent_req = map->common.request;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-        *parent_req = NULL;
-    }
+    input.rcxt_num  = rc->c_version;
 
 #if H5VL_IOD_DEBUG
-    printf("MAP EXISTS, axe id %llu, parent %llu\n", 
-           input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("MAP EXISTS, axe id %llu\n", g_axe_id);
 #endif
 
     if(H5VL__iod_create_and_forward(H5VL_MAP_EXISTS_ID, HG_MAP_EXISTS, 
                                     (H5VL_iod_object_t *)map, 0,
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, exists, exists, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)rc, &input, exists, exists, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship map exists");
 
 done:
@@ -6080,7 +6135,9 @@ H5VL_iod_map_delete(void *_map, hid_t key_mem_type_id, const void *key,
     map_op_in_t input;
     size_t key_size;
     int *status = NULL;
-    H5VL_iod_request_t **parent_req = NULL;
+    size_t num_parents = 0;
+    H5TR_t *tr;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -6094,9 +6151,19 @@ H5VL_iod_map_delete(void *_map, hid_t key_mem_type_id, const void *key,
         key_size = H5T_GET_SIZE(dt);
     }
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    /* get the TR object */
+    if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a Transaction ID")
+
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *) * 2)))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests((H5VL_iod_object_t *)map, (H5VL_iod_req_info_t *)tr, 
+                                    parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
     /* Fill input structure */
     input.coh = map->common.file->remote_file.coh;
     input.iod_oh = map->remote_map.iod_oh;
@@ -6105,30 +6172,19 @@ H5VL_iod_map_delete(void *_map, hid_t key_mem_type_id, const void *key,
     input.key_memtype_id = key_mem_type_id;
     input.key.buf_size = key_size;
     input.key.buf = key;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != map->common.request && map->common.request->state != H5VL_IOD_COMPLETED) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &map->common.request->axe_id;
-        map->common.request->ref_count ++;
-        *parent_req = map->common.request;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-        *parent_req = NULL;
-    }
+    input.trans_num = tr->trans_num;
+    input.rcxt_num  = tr->c_version;
 
 #if H5VL_IOD_DEBUG
-    printf("MAP DELETE, axe id %llu, parent %llu\n", 
-           input.axe_info.axe_id, ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("MAP DELETE, axe id %llu\n", g_axe_id);
 #endif
 
     status = (int *)malloc(sizeof(int));
 
     if(H5VL__iod_create_and_forward(H5VL_MAP_DELETE_ID, HG_MAP_DELETE, 
                                     (H5VL_iod_object_t *)map, 1,
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, status, status, req) < 0)
+                                    num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)tr, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship map delete");
 
 done:
@@ -6140,8 +6196,7 @@ herr_t H5VL_iod_map_close(void *_map, void **req)
     H5VL_iod_map_t *map = (H5VL_iod_map_t *)_map;
     map_close_in_t input;
     int *status;
-    size_t num_parents;
-    AXE_task_t *parent_axe_ids = NULL;
+    size_t num_parents = 0;
     H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
@@ -6154,47 +6209,34 @@ herr_t H5VL_iod_map_close(void *_map, void **req)
             HGOTO_ERROR(H5E_SYM,  H5E_CANTGET, FAIL, "can't wait on all object requests");
     }
 
-    if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)map, &num_parents, NULL, NULL) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num AXE parents");
+    if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)map, &num_parents, NULL) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get num requests");
 
     if(num_parents) {
-        if(NULL == (parent_axe_ids = (AXE_task_t *)H5MM_malloc(sizeof(AXE_task_t) * num_parents)))
-            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent axe IDs");
         if(NULL == (parent_reqs = (H5VL_iod_request_t **)H5MM_malloc
                     (sizeof(H5VL_iod_request_t *) * num_parents)))
             HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent reqs");
-        if(H5VL_iod_get_axe_parents((H5VL_iod_object_t *)map, &num_parents, 
-                                    parent_axe_ids, parent_reqs) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get AXE parents");
+        if(H5VL_iod_get_obj_requests((H5VL_iod_object_t *)map, &num_parents, 
+                                     parent_reqs) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get parents requests");
     }
 
     input.iod_oh = map->remote_map.iod_oh;
     input.iod_id = map->remote_map.iod_id;
-    input.axe_info.num_parents = num_parents;
-    input.axe_info.parent_axe_ids = parent_axe_ids;
-    input.axe_info.axe_id = g_axe_id ++;
 
 #if H5VL_IOD_DEBUG
-    {
-        size_t i;
-
-        printf("Map Close %s, axe id %llu, %d parents: ", 
-               map->common.obj_name, input.axe_info.axe_id, num_parents);
-        for(i=0 ; i<num_parents ; i++)
-            printf("%llu ", parent_axe_ids[i]);
-        printf("\n");
-    }
+    printf("Map Close IOD ID %llu, axe id %llu\n", input.iod_id, g_axe_id);
 #endif
 
     status = (int *)malloc(sizeof(int));
 
-    if(H5VL__iod_create_and_forward(H5VL_MAP_CLOSE_ID, HG_MAP_CLOSE, (H5VL_iod_object_t *)map, 1,
+    if(H5VL__iod_create_and_forward(H5VL_MAP_CLOSE_ID, HG_MAP_CLOSE, 
+                                    (H5VL_iod_object_t *)map, 1,
                                     num_parents, parent_reqs,
-                                    &input, status, status, req) < 0)
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship map close");
 
 done:
-    parent_axe_ids = (AXE_task_t *)H5MM_xfree(parent_axe_ids);
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_iod_map_close() */
 
@@ -6425,9 +6467,6 @@ H5VL_iod_rc_acquire(H5VL_iod_file_t *file, H5RC_t *rc, uint64_t *c_version,
     input.coh = file->remote_file.coh;
     input.c_version = *c_version;
     input.rcapl_id = rcapl_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = 0;
-    input.axe_info.parent_axe_ids = NULL;
 
     /* setup the info structure for updating the RC on completion */
     if(NULL == (rc_info = (H5VL_iod_rc_info_t *)H5MM_calloc(sizeof(H5VL_iod_rc_info_t))))
@@ -6438,23 +6477,20 @@ H5VL_iod_rc_acquire(H5VL_iod_file_t *file, H5RC_t *rc, uint64_t *c_version,
 
 #if H5VL_IOD_DEBUG
     printf("Read Context Acquire, version %llu, axe id %llu\n", 
-           input.c_version, input.axe_info.axe_id);
+           input.c_version, g_axe_id);
 #endif
 
     if(H5VL__iod_create_and_forward(H5VL_RC_ACQUIRE_ID, HG_RC_ACQUIRE, 
                                     (H5VL_iod_object_t *)file, 0, 0, NULL,
-                                    &input, &rc_info->result, rc_info, req) < 0)
+                                    NULL, &input, &rc_info->result, rc_info, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship VOL op");
 
-#if 0
-    /* MSC - this is not needed because the user is repsonsible to wait on the acquire */
     if(NULL != req) {
         H5VL_iod_request_t *request = (H5VL_iod_request_t *)(*req);
 
-        rc->request = request;
-        request->ref_count ++;
+        rc->req_info.request = request;
+        //request->ref_count ++;
     }
-#endif
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -6479,35 +6515,89 @@ H5VL_iod_rc_release(H5RC_t *rc, void **req)
 {
     rc_release_in_t input;
     int *status = NULL;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)H5MM_malloc
+                (sizeof(H5VL_iod_request_t *) * (rc->req_info.num_req + 1))))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent reqs");
+
+    /* retrieve start request */
+    if(H5VL_iod_get_parent_requests(NULL, (H5VL_iod_req_info_t *)rc, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+    if(rc->req_info.num_req) {
+        H5VL_iod_request_t *cur_req = rc->req_info.head;
+        H5VL_iod_request_t *next_req = NULL;
+        H5VL_iod_request_t *prev;
+        H5VL_iod_request_t *next;
+
+        while(cur_req) {
+            if(cur_req->state == H5VL_IOD_PENDING) {
+                parent_reqs[num_parents] = cur_req;
+                cur_req->ref_count ++;
+                num_parents ++;
+            }
+
+            next_req = cur_req->trans_next;
+
+            /* remove the current request from the linked list */
+            prev = cur_req->trans_prev;
+            next = cur_req->trans_next;
+            if (prev) {
+                if (next) {
+                    prev->trans_next = next;
+                    next->trans_prev = prev;
+                }
+                else {
+                    prev->trans_next = NULL;
+                    rc->req_info.tail = prev;
+                }
+            }
+            else {
+                if (next) {
+                    next->trans_prev = NULL;
+                    rc->req_info.head = next;
+                }
+                else {
+                    rc->req_info.head = NULL;
+                    rc->req_info.tail = NULL;
+                }
+            }
+
+            cur_req->trans_prev = NULL;
+            cur_req->trans_next = NULL;
+
+            rc->req_info.num_req --;
+
+            cur_req = next_req;
+        }
+        HDassert(0 == rc->req_info.num_req);
+    }
+
     /* set the input structure for the HG encode routine */
     input.coh = rc->file->remote_file.coh;
     input.c_version = rc->c_version;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = 0;
-    input.axe_info.parent_axe_ids = NULL;
 
     status = (int *)malloc(sizeof(int));
 
 #if H5VL_IOD_DEBUG
     printf("Read Context Release, version %llu, axe id %llu\n", 
-           input.c_version, input.axe_info.axe_id);
+           input.c_version, g_axe_id);
 #endif
 
     if(H5VL__iod_create_and_forward(H5VL_RC_RELEASE_ID, HG_RC_RELEASE, 
-                                    (H5VL_iod_object_t *)rc->file, 0, 0, NULL,
-                                    &input, status, status, req) < 0)
+                                    (H5VL_iod_object_t *)rc->file, 0, 
+                                    num_parents, parent_reqs,
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship VOL op");
 
-#if 0
-    /* MSC - this is not needed because the user is repsonsible to wait on the acquire */
-    if(NULL != rc->request) {
-        H5VL_iod_request_decr_rc(rc->request);
-    }
-#endif
+    //if(NULL != rc->req_info.request) {
+    //H5VL_iod_request_decr_rc(rc->req_info.request);
+    //}
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -6539,20 +6629,17 @@ H5VL_iod_rc_persist(H5RC_t *rc, void **req)
     /* set the input structure for the HG encode routine */
     input.coh = rc->file->remote_file.coh;
     input.c_version = rc->c_version;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = 0;
-    input.axe_info.parent_axe_ids = NULL;
 
     status = (int *)malloc(sizeof(int));
 
 #if H5VL_IOD_DEBUG
     printf("Read Context Persist, version %llu, axe id %llu\n", 
-           input.c_version, input.axe_info.axe_id);
+           input.c_version, g_axe_id);
 #endif
 
     if(H5VL__iod_create_and_forward(H5VL_RC_PERSIST_ID, HG_RC_PERSIST, 
                                     (H5VL_iod_object_t *)rc->file, 0, 0, NULL,
-                                    &input, status, status, req) < 0)
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship VOL op");
 
 done:
@@ -6586,20 +6673,17 @@ H5VL_iod_rc_snapshot(H5RC_t *rc, const char *snapshot_name, void **req)
     input.coh = rc->file->remote_file.coh;
     input.c_version = rc->c_version;
     input.snapshot_name = snapshot_name;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = 0;
-    input.axe_info.parent_axe_ids = NULL;
 
     status = (int *)malloc(sizeof(int));
 
 #if H5VL_IOD_DEBUG
     printf("Read Context Snapshot, version %llu, axe id %llu\n", 
-           input.c_version, input.axe_info.axe_id);
+           input.c_version, g_axe_id);
 #endif
 
     if(H5VL__iod_create_and_forward(H5VL_RC_SNAPSHOT_ID, HG_RC_SNAPSHOT, 
                                     (H5VL_iod_object_t *)rc->file, 0, 0, NULL,
-                                    &input, status, status, req) < 0)
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship VOL op");
 
 done:
@@ -6633,27 +6717,22 @@ H5VL_iod_tr_start(H5TR_t *tr, hid_t trspl_id, void **req)
     input.coh = tr->file->remote_file.coh;
     input.trans_num = tr->trans_num;
     input.trspl_id = trspl_id;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = 0;
-    input.axe_info.parent_axe_ids = NULL;
 
     status = (int *)malloc(sizeof(int));
 
 #if H5VL_IOD_DEBUG
     printf("Transaction start, number %llu, axe id %llu\n", 
-           input.trans_num, input.axe_info.axe_id);
+           input.trans_num, g_axe_id);
 #endif
 
     if(H5VL__iod_create_and_forward(H5VL_TR_START_ID, HG_TR_START, 
                                     (H5VL_iod_object_t *)tr->file, 0, 0, NULL,
-                                    &input, status, status, req) < 0)
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship VOL op");
 
     if(NULL != req) {
         H5VL_iod_request_t *request = (H5VL_iod_request_t *)(*req);
-
-        tr->request = request;
-        request->ref_count ++;
+        tr->req_info.request = request;
     }
 
 done:
@@ -6679,52 +6758,92 @@ H5VL_iod_tr_finish(H5TR_t *tr, hbool_t acquire, hid_t trfpl_id, void **req)
 {
     tr_finish_in_t input;
     int *status = NULL;
-    H5VL_iod_request_t **parent_req = NULL;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)H5MM_malloc
+                (sizeof(H5VL_iod_request_t *) * (tr->req_info.num_req + 1))))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate array of parent reqs");
+
+    /* retrieve start request */
+    if(H5VL_iod_get_parent_requests(NULL, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
+    if(tr->req_info.num_req) {
+        H5VL_iod_request_t *cur_req = tr->req_info.head;
+        H5VL_iod_request_t *next_req = NULL;
+        H5VL_iod_request_t *prev;
+        H5VL_iod_request_t *next;
+
+        while(cur_req) {
+            /* add a dependency if the current request in the list is pending */
+            if(cur_req->state == H5VL_IOD_PENDING) {
+                parent_reqs[num_parents] = cur_req;
+                cur_req->ref_count ++;
+                num_parents ++;
+            }
+
+            next_req = cur_req->trans_next;
+
+            /* remove the current request from the linked list */
+            prev = cur_req->trans_prev;
+            next = cur_req->trans_next;
+            if (prev) {
+                if (next) {
+                    prev->trans_next = next;
+                    next->trans_prev = prev;
+                }
+                else {
+                    prev->trans_next = NULL;
+                    tr->req_info.tail = prev;
+                }
+            }
+            else {
+                if (next) {
+                    next->trans_prev = NULL;
+                    tr->req_info.head = next;
+                }
+                else {
+                    tr->req_info.head = NULL;
+                    tr->req_info.tail = NULL;
+                }
+            }
+
+            cur_req->trans_prev = NULL;
+            cur_req->trans_next = NULL;
+
+            tr->req_info.num_req --;
+
+            cur_req = next_req;
+        }
+        HDassert(0 == tr->req_info.num_req);
+    }
 
     /* set the input structure for the HG encode routine */
     input.coh = tr->file->remote_file.coh;
     input.trans_num = tr->trans_num;
     input.trfpl_id = trfpl_id;
     input.acquire = acquire;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = 0;
-    input.axe_info.parent_axe_ids = NULL;
-
-    if(NULL != tr->request && tr->request->state != H5VL_IOD_COMPLETED) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &tr->request->axe_id;
-        tr->request->ref_count ++;
-        *parent_req = tr->request;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-        *parent_req = NULL;
-    }
 
     status = (int *)malloc(sizeof(int));
 
 #if H5VL_IOD_DEBUG
-    printf("Transaction Finish, %llu, axe id %llu, Parent %llu\n", 
-           input.trans_num, input.axe_info.axe_id,
-           ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Transaction Finish, %llu, axe id %llu\n", 
+           input.trans_num, g_axe_id);
 #endif
 
     if(H5VL__iod_create_and_forward(H5VL_TR_FINISH_ID, HG_TR_FINISH, 
                                     (H5VL_iod_object_t *)tr->file, 0, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, status, status, req) < 0)
+                                    num_parents, parent_reqs,
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship VOL op");
 
-    if(NULL != tr->request) {
-        H5VL_iod_request_decr_rc(tr->request);
-    }
+    //if(NULL != tr->req_info.request) {
+    //H5VL_iod_request_decr_rc(tr->req_info.request);
+    //}
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -6749,44 +6868,36 @@ H5VL_iod_tr_set_dependency(H5TR_t *tr, uint64_t trans_num, void **req)
 {
     tr_set_depend_in_t input;
     int *status = NULL;
-    H5VL_iod_request_t **parent_req = NULL;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(NULL, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
     /* set the input structure for the HG encode routine */
     input.coh = tr->file->remote_file.coh;
     input.child_trans_num = tr->trans_num;
     input.parent_trans_num = trans_num;
-    input.axe_info.axe_id = g_axe_id ++;
-
-    if(NULL != tr->request && tr->request->state != H5VL_IOD_COMPLETED) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &tr->request->axe_id;
-        tr->request->ref_count ++;
-        *parent_req = tr->request;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-        *parent_req = NULL;
-    }
 
 #if H5VL_IOD_DEBUG
-    printf("Transaction Set Dependency, %llu on %llu axe id %llu, Parent %llu\n", 
-           input.child_trans_num, input.parent_trans_num, input.axe_info.axe_id,
-           ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Transaction Set Dependency, %llu on %llu axe id %llu\n", 
+           input.child_trans_num, input.parent_trans_num, g_axe_id);
 #endif
 
     status = (int *)malloc(sizeof(int));
 
     if(H5VL__iod_create_and_forward(H5VL_TR_SET_DEPEND_ID, HG_TR_SET_DEPEND, 
                                     (H5VL_iod_object_t *)tr->file, 0, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, status, status, req) < 0)
+                                    num_parents, parent_reqs,
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship VOL op");
 
 done:
@@ -6820,20 +6931,17 @@ H5VL_iod_tr_skip(H5VL_iod_file_t *file, uint64_t start_trans_num, uint64_t count
     input.coh = file->remote_file.coh;
     input.start_trans_num = start_trans_num;
     input.count = count;
-    input.axe_info.axe_id = g_axe_id ++;
-    input.axe_info.num_parents = 0;
-    input.axe_info.parent_axe_ids = NULL;
 
 #if H5VL_IOD_DEBUG
     printf("Transaction Skip, tr %llu count %llu,, axe id %llu\n", 
-           input.start_trans_num, input.count, input.axe_info.axe_id);
+           input.start_trans_num, input.count, g_axe_id);
 #endif
 
     status = (int *)malloc(sizeof(int));
 
     if(H5VL__iod_create_and_forward(H5VL_TR_SKIP_ID, HG_TR_SKIP, 
                                     (H5VL_iod_object_t *)file, 0, 0, NULL,
-                                    &input, status, status, req) < 0)
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship VOL op");
 
 done:
@@ -6859,42 +6967,78 @@ H5VL_iod_tr_abort(H5TR_t *tr, void **req)
 {
     tr_abort_in_t input;
     int *status = NULL;
-    H5VL_iod_request_t **parent_req = NULL;
+    size_t num_parents = 0;
+    H5VL_iod_request_t **parent_reqs = NULL;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    if(NULL == (parent_req = (H5VL_iod_request_t **)H5MM_malloc(sizeof(H5VL_iod_request_t *))))
+    if(NULL == (parent_reqs = (H5VL_iod_request_t **)
+                H5MM_malloc(sizeof(H5VL_iod_request_t *))))
         HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate parent req element");
 
+    /* retrieve parent requests */
+    if(H5VL_iod_get_parent_requests(NULL, (H5VL_iod_req_info_t *)tr, parent_reqs, &num_parents) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "Failed to retrieve parent requests");
+
     /* set the input structure for the HG encode routine */
     input.coh = tr->file->remote_file.coh;
     input.trans_num = tr->trans_num;
-    input.axe_info.axe_id = g_axe_id ++;
-    if(NULL != tr->request && tr->request->state != H5VL_IOD_COMPLETED) {
-        input.axe_info.num_parents = 1;
-        input.axe_info.parent_axe_ids = &tr->request->axe_id;
-        tr->request->ref_count ++;
-        *parent_req = tr->request;
-    }
-    else {
-        input.axe_info.num_parents = 0;
-        input.axe_info.parent_axe_ids = NULL;
-        *parent_req = NULL;
+
+    /* remove all nodes from the transaction linked list */
+    if(tr->req_info.num_req) {
+        H5VL_iod_request_t *cur_req = tr->req_info.head;
+        H5VL_iod_request_t *next_req = NULL;
+        H5VL_iod_request_t *prev;
+        H5VL_iod_request_t *next;
+
+        while(cur_req) {
+            next_req = cur_req->trans_next;
+
+            prev = cur_req->trans_prev;
+            next = cur_req->trans_next;
+            if (prev) {
+                if (next) {
+                    prev->trans_next = next;
+                    next->trans_prev = prev;
+                }
+                else {
+                    prev->trans_next = NULL;
+                    tr->req_info.tail = prev;
+                }
+            }
+            else {
+                if (next) {
+                    next->trans_prev = NULL;
+                    tr->req_info.head = next;
+                }
+                else {
+                    tr->req_info.head = NULL;
+                    tr->req_info.tail = NULL;
+                }
+            }
+
+            cur_req->trans_prev = NULL;
+            cur_req->trans_next = NULL;
+
+            tr->req_info.num_req --;
+
+            cur_req = next_req;
+        }
+        HDassert(0 == tr->req_info.num_req);
     }
 
     status = (int *)malloc(sizeof(int));
 
 #if H5VL_IOD_DEBUG
-    printf("Transaction Abort, tr %llu, axe id %llu, Parent %llu\n", 
-           input.trans_num, input.axe_info.axe_id,
-           ((input.axe_info.parent_axe_ids!=NULL) ? input.axe_info.parent_axe_ids[0] : 0));
+    printf("Transaction Abort, tr %llu, axe id %llu\n", 
+           input.trans_num, g_axe_id);
 #endif
 
     if(H5VL__iod_create_and_forward(H5VL_TR_ABORT_ID, HG_TR_ABORT, 
                                     (H5VL_iod_object_t *)tr->file, 0, 
-                                    input.axe_info.num_parents, parent_req,
-                                    &input, status, status, req) < 0)
+                                    num_parents, parent_reqs,
+                                    NULL, &input, status, status, req) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship VOL op");
 
 done:
diff --git a/src/H5VLiod_attr.c b/src/H5VLiod_attr.c
index 06838a7..afa0b85 100644
--- a/src/H5VLiod_attr.c
+++ b/src/H5VLiod_attr.c
@@ -51,6 +51,8 @@ H5VL_iod_server_attr_create_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t loc_handle = input->loc_oh; /* location handle to start lookup */
     iod_obj_id_t loc_id = input->loc_id; /* The ID of the current location object */
     iod_obj_id_t attr_id = input->attr_id; /* The ID of the attribute that needs to be created */
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t attr_oh, attr_kv_oh, obj_oh, mdkv_oh; /* object handles */
     iod_obj_id_t obj_id, mdkv_id;
     const char *loc_name = input->path; /* path to start hierarchy traversal */
@@ -220,6 +222,7 @@ H5VL_iod_server_attr_open_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t coh = input->coh; /* container handle */
     iod_handle_t loc_handle = input->loc_oh; /* location handle to start traversal */
     iod_obj_id_t loc_id = input->loc_id; /* location ID */
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t attr_kv_oh, attr_oh, obj_oh, mdkv_oh;
     iod_obj_id_t obj_id;
     iod_obj_id_t attr_id;
@@ -372,6 +375,7 @@ H5VL_iod_server_attr_read_cb(AXE_engine_t UNUSED axe_engine,
     iod_obj_id_t iod_id = input->iod_id; /* attribute's ID */
     hg_bulk_t bulk_handle = input->bulk_handle; /* bulk handle for data */
     hid_t type_id = input->type_id; /* datatype ID of data */
+    iod_trans_id_t rtid = input->rcxt_num;
     hg_bulk_block_t bulk_block_handle; /* HG block handle */
     hg_bulk_request_t bulk_request; /* HG request */
     iod_mem_desc_t mem_desc; /* memory descriptor used for reading array */
@@ -520,6 +524,8 @@ H5VL_iod_server_attr_write_cb(AXE_engine_t UNUSED axe_engine,
     iod_obj_id_t iod_id = input->iod_id; /* attribute's ID */
     hg_bulk_t bulk_handle = input->bulk_handle; /* bulk handle for data */
     hid_t type_id = input->type_id; /* datatype ID of data */
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     hg_bulk_block_t bulk_block_handle; /* HG block handle */
     hg_bulk_request_t bulk_request; /* HG request */
     iod_mem_desc_t mem_desc; /* memory descriptor used for writing array */
@@ -667,6 +673,7 @@ H5VL_iod_server_attr_exists_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t coh = input->coh; /* container handle */
     iod_handle_t loc_handle = input->loc_oh; /* location handle to start lookup */
     iod_obj_id_t loc_id = input->loc_id; /* The ID of the current location object */
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t obj_oh; /* current object handle accessed */
     iod_handle_t attr_kv_oh; /* KV handle holding attributes for object */
     iod_obj_id_t obj_id;
@@ -772,6 +779,8 @@ H5VL_iod_server_attr_rename_cb(AXE_engine_t UNUSED axe_engine,
     const char *loc_name = input->path; /* path to start hierarchy traversal */
     const char *old_name = input->old_attr_name;
     const char *new_name = input->new_attr_name;
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_kv_params_t kvs; /* KV lists for objects - used to unlink attribute object */
     iod_kv_t kv; /* KV entry */
     H5VL_iod_link_t iod_link;
@@ -880,6 +889,8 @@ H5VL_iod_server_attr_remove_cb(AXE_engine_t UNUSED axe_engine,
     iod_obj_id_t obj_id, attr_id;
     const char *loc_name = input->path; /* path to start hierarchy traversal */
     const char *attr_name = input->attr_name; /* attribute's name */
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_kv_params_t kvs;
     iod_kv_t kv;
     H5VL_iod_link_t iod_link;
diff --git a/src/H5VLiod_client.c b/src/H5VLiod_client.c
index 4e126e9..def20e9 100644
--- a/src/H5VLiod_client.c
+++ b/src/H5VLiod_client.c
@@ -68,7 +68,7 @@ H5VL_iod_request_decr_rc(H5VL_iod_request_t *request)
     request->ref_count --;
 
     if(0 == request->ref_count) {
-        request->parent_reqs = (H5VL_iod_request_t **)H5MM_xfree(request->parent_reqs);
+        //request->parent_reqs = (H5VL_iod_request_t **)H5MM_xfree(request->parent_reqs);
         request = (H5VL_iod_request_t *)H5MM_xfree(request);
     }
 
@@ -89,24 +89,40 @@ H5VL_iod_request_decr_rc(H5VL_iod_request_t *request)
 herr_t
 H5VL_iod_request_add(H5VL_iod_file_t *file, H5VL_iod_request_t *request)
 {
+    H5VL_iod_req_info_t *req_info = request->trans_info;
+
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
     HDassert(request);
 
     if (file->request_list_tail) {
-        file->request_list_tail->next = request;
-        request->prev = file->request_list_tail;
+        file->request_list_tail->file_next = request;
+        request->file_prev = file->request_list_tail;
         file->request_list_tail = request;
     }
     else {
         file->request_list_head = request;
         file->request_list_tail = request;
-        request->prev = NULL;
+        request->file_prev = NULL;
     }
-    request->next = NULL;
-
+    request->file_next = NULL;
     file->num_req ++;
 
+    if(req_info) {
+        if (req_info->tail) {
+            req_info->tail->trans_next = request;
+            request->trans_prev = req_info->tail;
+            req_info->tail = request;
+        }
+        else {
+            req_info->head = request;
+            req_info->tail = request;
+            request->trans_prev = NULL;
+        }
+        request->trans_next = NULL;
+        req_info->num_req ++;
+    }
+
     FUNC_LEAVE_NOAPI(SUCCEED)
 }
 
@@ -138,21 +154,24 @@ H5VL_iod_request_delete(H5VL_iod_file_t *file, H5VL_iod_request_t *request)
         H5VL_iod_request_decr_rc(request->parent_reqs[u]);
     }
 
-    prev = request->prev;
-    next = request->next;
+    request->parent_reqs = (H5VL_iod_request_t **)H5MM_xfree(request->parent_reqs);
+
+    /* remove the request from the container link list */
+    prev = request->file_prev;
+    next = request->file_next;
     if (prev) {
         if (next) {
-            prev->next = next;
-            next->prev = prev;
+            prev->file_next = next;
+            next->file_prev = prev;
         }
         else {
-            prev->next = NULL;
+            prev->file_next = NULL;
             file->request_list_tail = prev;
         }
     }
     else {
         if (next) {
-            next->prev = NULL;
+            next->file_prev = NULL;
             file->request_list_head = next;
         }
         else {
@@ -163,8 +182,8 @@ H5VL_iod_request_delete(H5VL_iod_file_t *file, H5VL_iod_request_t *request)
 
     if(request == request->obj->request)
         request->obj->request = NULL;
-    request->prev = NULL;
-    request->next = NULL;
+    request->file_prev = NULL;
+    request->file_next = NULL;
 
     file->num_req --;
 
@@ -228,7 +247,7 @@ H5VL_iod_request_wait(H5VL_iod_file_t *file, H5VL_iod_request_t *request)
                 if(HG_FILE_CLOSE != cur_req->type && cur_req->req != request->req) {
                     hg_status_t tmp_status;
 
-                    tmp_req = cur_req->next;
+                    tmp_req = cur_req->file_next;
 
                     HDassert(cur_req->state == H5VL_IOD_PENDING);
                     ret = HG_Wait(*((hg_request_t *)cur_req->req), 0, &tmp_status);
@@ -288,7 +307,7 @@ H5VL_iod_request_wait_all(H5VL_iod_file_t *file)
     while(cur_req) {
         H5VL_iod_request_t *tmp_req = NULL;
 
-        tmp_req = cur_req->next;
+        tmp_req = cur_req->file_next;
 
         HDassert(cur_req->state == H5VL_IOD_PENDING);
         ret = HG_Wait(*((hg_request_t *)cur_req->req), HG_MAX_IDLE_TIME, &status);
@@ -346,7 +365,7 @@ H5VL_iod_request_wait_some(H5VL_iod_file_t *file, const void *object)
     while(cur_req) {
         H5VL_iod_request_t *tmp_req;
 
-        tmp_req = cur_req->next;
+        tmp_req = cur_req->file_next;
 
         /* If the request is pending on the object we want, complete it */
         if(cur_req->obj == object) {
@@ -557,8 +576,9 @@ H5VL_iod_request_complete(H5VL_iod_file_t *file, H5VL_iod_request_t *req)
                 H5VL_iod_dset_t *dset = (H5VL_iod_dset_t *)req->obj;
                 uint32_t internal_cs = 0;
                 size_t buf_size = status->buf_size;
-                hg_status_t hg_status;
-                hg_request_t hg_req;       /* Local function shipper request */
+                hid_t rcxt_id;
+                H5RC_t *rc;
+                H5P_genplist_t *plist = NULL;
                 H5VL_iod_read_status_t vl_status;
 
                 if(NULL == (read_buf = (void *)HDmalloc(buf_size)))
@@ -569,6 +589,16 @@ H5VL_iod_request_complete(H5VL_iod_file_t *file, H5VL_iod_request_t *req)
                                                        HG_BULK_READWRITE, info->bulk_handle))
                     HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "can't create Bulk Data Handle");
 
+                /* get the context ID */
+                if(NULL == (plist = (H5P_genplist_t *)H5I_object(info->dxpl_id)))
+                    HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+                if(H5P_get(plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+                    HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get property value for trans_id");
+
+                /* get the RC object */
+                if(NULL == (rc = (H5RC_t *)H5I_object_verify(rcxt_id, H5I_RC)))
+                    HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a READ CONTEXT ID")
+
                 /* Fill input structure for reading data */
                 input.coh = file->remote_file.coh;
                 input.iod_oh = dset->remote_dset.iod_oh;
@@ -579,27 +609,12 @@ H5VL_iod_request_complete(H5VL_iod_file_t *file, H5VL_iod_request_t *req)
                 input.space_id = info->file_space_id;
                 input.mem_type_id = info->mem_type_id;
                 input.dset_type_id = dset->remote_dset.type_id;
-                input.axe_info.axe_id = info->axe_id;
-                input.axe_info.num_parents = 0;
-                input.axe_info.parent_axe_ids = NULL;
-
-                input.axe_info.start_range = 0;
-                input.axe_info.count = 0;
-
-                /* forward call to IONs */
-                if(HG_Forward(info->peer, info->read_id, &input, &vl_status, &hg_req) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to ship dataset read");
 
-                if(HG_Wait(hg_req, HG_MAX_IDLE_TIME, &hg_status) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to wait on mercury handle");
-
-                if(!hg_status) {
-                    fprintf(stderr, "Wait timeout reached\n");
-                    req->status = H5AO_FAILED;
-                    req->state = H5VL_IOD_COMPLETED;
-                    H5VL_iod_request_delete(file, req);
-                    goto done;
-                }
+                if(H5VL__iod_create_and_forward(info->read_id, HG_DSET_READ, 
+                                                (H5VL_iod_object_t *)dset, 0, 0, NULL,
+                                                (H5VL_iod_req_info_t *)rc,
+                                                &input, &vl_status, NULL, NULL) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "failed to create and ship dataset read");
 
                 /* Free memory handle */
                 if(HG_SUCCESS != HG_Bulk_handle_free(*info->bulk_handle)) {
@@ -753,22 +768,6 @@ H5VL_iod_request_complete(H5VL_iod_file_t *file, H5VL_iod_request_t *req)
             H5VL_iod_request_delete(file, req);
             break;
         }
-    case HG_FILE_FLUSH:
-        {
-            int *status = (int *)req->data;
-
-            if(SUCCEED != *status) {
-                fprintf(stderr, "File flush failed at the server\n");
-                req->status = H5AO_FAILED;
-                req->state = H5VL_IOD_COMPLETED;
-            }
-
-            free(status);
-            req->data = NULL;
-            file->common.request = NULL;
-            H5VL_iod_request_delete(file, req);
-            break;
-        }
     case HG_FILE_CLOSE:
         {
             int *status = (int *)req->data;
@@ -1212,16 +1211,6 @@ H5VL_iod_request_cancel(H5VL_iod_file_t *file, H5VL_iod_request_t *req)
             H5VL_iod_request_delete(file, req);
             break;
         }
-    case HG_FILE_FLUSH:
-        {
-            int *status = (int *)req->data;
-
-            free(status);
-            req->data = NULL;
-            file->common.request = NULL;
-            H5VL_iod_request_delete(file, req);
-            break;
-        }
     case HG_FILE_CREATE:
     case HG_FILE_OPEN:
     case HG_FILE_CLOSE:
@@ -1489,6 +1478,8 @@ H5VL_iod_request_cancel(H5VL_iod_file_t *file, H5VL_iod_request_t *req)
             break;
         }
     case HG_RC_RELEASE:
+    case HG_RC_PERSIST:
+    case HG_RC_SNAPSHOT:
     case HG_TR_START:
     case HG_TR_FINISH:
     case HG_TR_SET_DEPEND:
@@ -1515,20 +1506,19 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5VL_iod_get_axe_parents
+ * Function:    H5VL_iod_get_obj_requests
  *
- * Purpose:     returns the number of axe_id tasks that are associated 
+ * Purpose:     returns the number of requests that are associated 
  *              with a particular object. If the parent array is not NULL, 
- *              the axe_ids are returned in parents too.
+ *              the request pointers are stored.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5VL_iod_get_axe_parents(H5VL_iod_object_t *obj, /*IN/OUT*/ size_t *count, 
-                         /*OUT*/ AXE_task_t *parent_axe_ids, 
-                         /*OUT*/ H5VL_iod_request_t **parent_reqs)
+H5VL_iod_get_obj_requests(H5VL_iod_object_t *obj, /*IN/OUT*/ size_t *count, 
+                          /*OUT*/ H5VL_iod_request_t **parent_reqs)
 {
     H5VL_iod_file_t *file = obj->file;
     H5VL_iod_request_t *cur_req = file->request_list_head;
@@ -1540,9 +1530,6 @@ H5VL_iod_get_axe_parents(H5VL_iod_object_t *obj, /*IN/OUT*/ size_t *count,
         /* If the request is pending on the object we want, add its axe_id */
         if(cur_req->obj == obj) {
             if(cur_req->status == H5AO_PENDING) {
-                if(NULL != parent_axe_ids) {
-                    parent_axe_ids[size] = cur_req->axe_id;
-                }
                 if(NULL != parent_reqs) {
                     parent_reqs[size] = cur_req;
                     cur_req->ref_count ++;
@@ -1550,196 +1537,93 @@ H5VL_iod_get_axe_parents(H5VL_iod_object_t *obj, /*IN/OUT*/ size_t *count,
                 size ++;
             }
         }
-        cur_req = cur_req->next;
+        cur_req = cur_req->file_next;
     }
 
     *count = size;
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5VL_iod_get_axe_parents */
+} /* end H5VL_iod_get_obj_requests */
 
-
-/*-------------------------------------------------------------------------
- * Function:    H5VL_iod_get_parent_info
- *
- * Purpose:     This routine traverses the path in name, or in loc_params 
- *              if the path is specified there, to determine the components
- *              of the path that are present locally in the ID space. 
- *              Once a component in the path is not found, the routine
- *              breaks at that point and stores the remaining path in new_name.
- *              This is where the traversal can begin at the server. 
- *              The IOD ID, OH, and axe_id belonging to the last object 
- *              present are returned too. 
- *
- * Return:	Non-negative on success/Negative on failure
- *
- *-------------------------------------------------------------------------
- */
 herr_t
-H5VL_iod_get_parent_info(H5VL_iod_object_t *obj, H5VL_loc_params_t loc_params, 
-                         const char *name, /*OUT*/iod_obj_id_t *iod_id, 
-                         /*OUT*/iod_handle_t *iod_oh, /*OUT*/H5VL_iod_request_t **parent_req, 
-                         /*OUT*/char **new_name, /*OUT*/H5VL_iod_object_t **last_obj)
+H5VL_iod_get_loc_info(H5VL_iod_object_t *obj, iod_obj_id_t *iod_id, 
+                      iod_handle_t *iod_oh)
 {
-    iod_obj_id_t cur_id;
-    iod_handle_t cur_oh;
-    size_t cur_size; /* current size of the path traversed so far */
-    char *cur_name;  /* full path to object that is currently being looked for */
-    H5VL_iod_object_t *cur_obj = obj;   /* current object in the traversal loop */
-    H5VL_iod_object_t *next_obj = NULL; /* the next object to traverse */
-    const char *path;        /* specified path for the object to traverse to */
-    H5WB_t *wb = NULL;       /* Wrapped buffer for temporary buffer */
-    char comp_buf[1024];     /* Temporary buffer for path components */
-    char *comp;              /* Pointer to buffer for path components */
-    size_t nchars;	     /* component name length	*/
-    H5VL_iod_file_t *file = obj->file; /* pointer to file where the search happens */
-    hbool_t last_comp = FALSE; /* Flag to indicate that a component is the last component in the name */
+    iod_obj_id_t id;
+    iod_handle_t oh;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    if(loc_params.type == H5VL_OBJECT_BY_SELF)
-        path = name;
-    else if (loc_params.type == H5VL_OBJECT_BY_NAME)
-        path = loc_params.loc_data.loc_by_name.name;
-
-    if (NULL == (cur_name = (char *)malloc(HDstrlen(obj->obj_name) + HDstrlen(path) + 2)))
-	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "can't allocate");
-
-    HDstrcpy(cur_name, obj->obj_name);
-    cur_size = HDstrlen(obj->obj_name);
-
-    if(obj->obj_type != H5I_FILE) {
-        HDstrcat(cur_name, "/");
-        cur_size += 1;
-    }
-        
-    /* Wrap the local buffer for serialized header info */
-    if(NULL == (wb = H5WB_wrap(comp_buf, sizeof(comp_buf))))
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't wrap buffer")
-    /* Get a pointer to a buffer that's large enough  */
-    if(NULL == (comp = (char *)H5WB_actual(wb, (HDstrlen(path) + 1))))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't get actual buffer")
-
-    /* Traverse the path */
-    while((path = H5G__component(path, &nchars)) && *path) {
-        const char *s;                  /* Temporary string pointer */
-
-	/*
-	 * Copy the component name into a null-terminated buffer so
-	 * we can pass it down to the other symbol table functions.
-	 */
-	HDmemcpy(comp, path, nchars);
-	comp[nchars] = '\0';
-
-	/*
-	 * The special name `.' is a no-op.
-	 */
-	if('.' == comp[0] && !comp[1]) {
-	    path += nchars;
-	    continue;
-	} /* end if */
-
-        /* Check if this is the last component of the name */
-        if(!((s = H5G__component(path + nchars, NULL)) && *s))
-            last_comp = TRUE;
-
-        HDstrcat(cur_name, comp);
-        cur_size += nchars;
-        cur_name[cur_size] = '\0';
-
-        if(NULL == (next_obj = (const H5VL_iod_object_t *)H5I_search_name(file, cur_name, H5I_GROUP))) {
-            if(last_comp) {
-                if(NULL == (next_obj = (const H5VL_iod_object_t *)H5I_search_name
-                            (file, cur_name, H5I_DATASET))
-                   && NULL == (next_obj = (H5VL_iod_object_t *)H5I_search_name
-                               (file, cur_name, H5I_DATATYPE))
-                   && NULL == (next_obj = (H5VL_iod_object_t *)H5I_search_name
-                               (file, cur_name, H5I_MAP)))
-                    break;
-            }
-            else {
-                break;
-            }
-        }
-
-#if H5VL_IOD_DEBUG
-        printf("Found %s Locally\n", comp);
-#endif
-
-	/* Advance to next component in string */
-	path += nchars;
-        HDstrcat(cur_name, "/");
-        cur_size += 1;
-        cur_obj = next_obj;
-    }
-
-    switch(cur_obj->obj_type) {
+    switch(obj->obj_type) {
         case H5I_FILE:
-            cur_oh = cur_obj->file->remote_file.root_oh;
-            cur_id = cur_obj->file->remote_file.root_id;
+            oh = obj->file->remote_file.root_oh;
+            id = obj->file->remote_file.root_id;
             break;
         case H5I_GROUP:
-            cur_oh = ((const H5VL_iod_group_t *)cur_obj)->remote_group.iod_oh;
-            cur_id = ((const H5VL_iod_group_t *)cur_obj)->remote_group.iod_id;
+            oh = ((const H5VL_iod_group_t *)obj)->remote_group.iod_oh;
+            id = ((const H5VL_iod_group_t *)obj)->remote_group.iod_id;
             break;
         case H5I_DATASET:
-            cur_oh = ((const H5VL_iod_dset_t *)cur_obj)->remote_dset.iod_oh;
-            cur_id = ((const H5VL_iod_dset_t *)cur_obj)->remote_dset.iod_id;
+            oh = ((const H5VL_iod_dset_t *)obj)->remote_dset.iod_oh;
+            id = ((const H5VL_iod_dset_t *)obj)->remote_dset.iod_id;
             break;
         case H5I_DATATYPE:
-            cur_oh = ((const H5VL_iod_dtype_t *)cur_obj)->remote_dtype.iod_oh;
-            cur_id = ((const H5VL_iod_dtype_t *)cur_obj)->remote_dtype.iod_id;
+            oh = ((const H5VL_iod_dtype_t *)obj)->remote_dtype.iod_oh;
+            id = ((const H5VL_iod_dtype_t *)obj)->remote_dtype.iod_id;
             break;
         case H5I_MAP:
-            cur_oh = ((const H5VL_iod_map_t *)cur_obj)->remote_map.iod_oh;
-            cur_id = ((const H5VL_iod_map_t *)cur_obj)->remote_map.iod_id;
+            oh = ((const H5VL_iod_map_t *)obj)->remote_map.iod_oh;
+            id = ((const H5VL_iod_map_t *)obj)->remote_map.iod_id;
             break;
         default:
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "bad location object");
     }
 
-    if(cur_obj->request && cur_obj->request->status == H5AO_PENDING) {
-        *parent_req = cur_obj->request;
-        cur_obj->request->ref_count ++;
-    }
-    else {
-        *parent_req = NULL;
-        HDassert(cur_oh.cookie != IOD_OH_UNDEFINED);
-    }
-
-    *iod_id = cur_id;
-    *iod_oh = cur_oh;
-
-    if(*path)
-        *new_name = strdup(path);
-    else
-        *new_name = strdup(".");
-
-    if(last_obj)
-        *last_obj = cur_obj;
+    *iod_id = id;
+    *iod_oh = oh;
 
 done:
-    free(cur_name);
-    /* Release temporary component buffer */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_SYM, H5E_CANTRELEASE, FAIL, "can't release wrapped buffer")
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5VL_iod_get_parent_info */
+} /* end H5VL_iod_get_loc_info() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5VL_iod_get_axe_parents
+ * Function:    H5VL_iod_get_parent_requests
  *
- * Purpose:     routine to generate an IOD ID based on the object type, 
- *              rank and total ranks, and current index or 
- *              number of pre-existing IDs.
+ * Purpose:     Returns the parent requests associated with an object 
+ *              and transaction.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  *-------------------------------------------------------------------------
  */
 herr_t
+H5VL_iod_get_parent_requests(H5VL_iod_object_t *obj, H5VL_iod_req_info_t *req_info, 
+                             H5VL_iod_request_t **parent_reqs, size_t *num_parents)
+{
+    size_t count = 0;
+
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    if(obj && obj->request && obj->request->status == H5AO_PENDING) {
+        parent_reqs[count] = obj->request;
+        obj->request->ref_count ++;
+        count ++;
+    }
+
+    if(req_info && req_info->request && req_info->request->status == H5AO_PENDING) {
+        parent_reqs[count] = req_info->request;
+        req_info->request->ref_count ++;
+        count ++;
+    }
+
+    *num_parents += count;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5VL_iod_get_parent_requests */
+
+herr_t
 H5VL_iod_gen_obj_id(int myrank, int nranks, uint64_t cur_index, 
                     iod_obj_type_t type, uint64_t *id)
 {
@@ -2371,6 +2255,174 @@ H5VL_iod_get_axe_id(int myrank, int nranks, int cur_index, uint64_t *id)
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 }
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL_iod_get_parent_info
+ *
+ * Purpose:     This routine traverses the path in name, or in loc_params 
+ *              if the path is specified there, to determine the components
+ *              of the path that are present locally in the ID space. 
+ *              Once a component in the path is not found, the routine
+ *              breaks at that point and stores the remaining path in new_name.
+ *              This is where the traversal can begin at the server. 
+ *              The IOD ID, OH, and axe_id belonging to the last object 
+ *              present are returned too. 
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VL_iod_get_parent_info(H5VL_iod_object_t *obj, H5VL_loc_params_t loc_params, 
+                         const char *name, /*OUT*/iod_obj_id_t *iod_id, 
+                         /*OUT*/iod_handle_t *iod_oh, /*OUT*/H5VL_iod_request_t **parent_req, 
+                         /*OUT*/char **new_name, /*OUT*/H5VL_iod_object_t **last_obj)
+{
+    iod_obj_id_t cur_id;
+    iod_handle_t cur_oh;
+    size_t cur_size; /* current size of the path traversed so far */
+    char *cur_name;  /* full path to object that is currently being looked for */
+    H5VL_iod_object_t *cur_obj = obj;   /* current object in the traversal loop */
+    H5VL_iod_object_t *next_obj = NULL; /* the next object to traverse */
+    const char *path;        /* specified path for the object to traverse to */
+    H5WB_t *wb = NULL;       /* Wrapped buffer for temporary buffer */
+    char comp_buf[1024];     /* Temporary buffer for path components */
+    char *comp;              /* Pointer to buffer for path components */
+    size_t nchars;	     /* component name length	*/
+    H5VL_iod_file_t *file = obj->file; /* pointer to file where the search happens */
+    hbool_t last_comp = FALSE; /* Flag to indicate that a component is the last component in the name */
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    if(loc_params.type == H5VL_OBJECT_BY_SELF)
+        path = name;
+    else if (loc_params.type == H5VL_OBJECT_BY_NAME)
+        path = loc_params.loc_data.loc_by_name.name;
+
+    if (NULL == (cur_name = (char *)malloc(HDstrlen(obj->obj_name) + HDstrlen(path) + 2)))
+	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "can't allocate");
+
+    HDstrcpy(cur_name, obj->obj_name);
+    cur_size = HDstrlen(obj->obj_name);
+
+    if(obj->obj_type != H5I_FILE) {
+        HDstrcat(cur_name, "/");
+        cur_size += 1;
+    }
+        
+    /* Wrap the local buffer for serialized header info */
+    if(NULL == (wb = H5WB_wrap(comp_buf, sizeof(comp_buf))))
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't wrap buffer")
+    /* Get a pointer to a buffer that's large enough  */
+    if(NULL == (comp = (char *)H5WB_actual(wb, (HDstrlen(path) + 1))))
+        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't get actual buffer")
+
+    /* Traverse the path */
+    while((path = H5G__component(path, &nchars)) && *path) {
+        const char *s;                  /* Temporary string pointer */
+
+	/*
+	 * Copy the component name into a null-terminated buffer so
+	 * we can pass it down to the other symbol table functions.
+	 */
+	HDmemcpy(comp, path, nchars);
+	comp[nchars] = '\0';
+
+	/*
+	 * The special name `.' is a no-op.
+	 */
+	if('.' == comp[0] && !comp[1]) {
+	    path += nchars;
+	    continue;
+	} /* end if */
+
+        /* Check if this is the last component of the name */
+        if(!((s = H5G__component(path + nchars, NULL)) && *s))
+            last_comp = TRUE;
+
+        HDstrcat(cur_name, comp);
+        cur_size += nchars;
+        cur_name[cur_size] = '\0';
+
+        if(NULL == (next_obj = (const H5VL_iod_object_t *)H5I_search_name(file, cur_name, H5I_GROUP))) {
+            if(last_comp) {
+                if(NULL == (next_obj = (const H5VL_iod_object_t *)H5I_search_name
+                            (file, cur_name, H5I_DATASET))
+                   && NULL == (next_obj = (H5VL_iod_object_t *)H5I_search_name
+                               (file, cur_name, H5I_DATATYPE))
+                   && NULL == (next_obj = (H5VL_iod_object_t *)H5I_search_name
+                               (file, cur_name, H5I_MAP)))
+                    break;
+            }
+            else {
+                break;
+            }
+        }
+
+#if H5VL_IOD_DEBUG
+        printf("Found %s Locally\n", comp);
+#endif
+
+	/* Advance to next component in string */
+	path += nchars;
+        HDstrcat(cur_name, "/");
+        cur_size += 1;
+        cur_obj = next_obj;
+    }
+
+    switch(cur_obj->obj_type) {
+        case H5I_FILE:
+            cur_oh = cur_obj->file->remote_file.root_oh;
+            cur_id = cur_obj->file->remote_file.root_id;
+            break;
+        case H5I_GROUP:
+            cur_oh = ((const H5VL_iod_group_t *)cur_obj)->remote_group.iod_oh;
+            cur_id = ((const H5VL_iod_group_t *)cur_obj)->remote_group.iod_id;
+            break;
+        case H5I_DATASET:
+            cur_oh = ((const H5VL_iod_dset_t *)cur_obj)->remote_dset.iod_oh;
+            cur_id = ((const H5VL_iod_dset_t *)cur_obj)->remote_dset.iod_id;
+            break;
+        case H5I_DATATYPE:
+            cur_oh = ((const H5VL_iod_dtype_t *)cur_obj)->remote_dtype.iod_oh;
+            cur_id = ((const H5VL_iod_dtype_t *)cur_obj)->remote_dtype.iod_id;
+            break;
+        case H5I_MAP:
+            cur_oh = ((const H5VL_iod_map_t *)cur_obj)->remote_map.iod_oh;
+            cur_id = ((const H5VL_iod_map_t *)cur_obj)->remote_map.iod_id;
+            break;
+        default:
+            HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "bad location object");
+    }
+
+    if(cur_obj->request && cur_obj->request->status == H5AO_PENDING) {
+        *parent_req = cur_obj->request;
+        cur_obj->request->ref_count ++;
+    }
+    else {
+        *parent_req = NULL;
+        HDassert(cur_oh.cookie != IOD_OH_UNDEFINED);
+    }
+
+    *iod_id = cur_id;
+    *iod_oh = cur_oh;
+
+    if(*path)
+        *new_name = strdup(path);
+    else
+        *new_name = strdup(".");
+
+    if(last_obj)
+        *last_obj = cur_obj;
+
+done:
+    free(cur_name);
+    /* Release temporary component buffer */
+    if(wb && H5WB_unwrap(wb) < 0)
+        HDONE_ERROR(H5E_SYM, H5E_CANTRELEASE, FAIL, "can't release wrapped buffer")
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL_iod_get_parent_info */
 #endif
 
 #endif /* H5_HAVE_EFF */
diff --git a/src/H5VLiod_client.h b/src/H5VLiod_client.h
index cc6edc2..b6b43e7 100644
--- a/src/H5VLiod_client.h
+++ b/src/H5VLiod_client.h
@@ -29,13 +29,13 @@
 
 /* forward declaration of file struct */
 struct H5VL_iod_file_t;
+/* forward declaration of object struct */
 struct H5VL_iod_object_t;
 
-/* types for requests */
+/* enum for types of requests */
 typedef enum H5RQ_type_t {
     HG_FILE_CREATE,
     HG_FILE_OPEN,
-    HG_FILE_FLUSH,
     HG_FILE_CLOSE,
     HG_ATTR_CREATE,
     HG_ATTR_OPEN,
@@ -94,20 +94,30 @@ typedef enum H5RQ_type_t {
 
 /* the client IOD VOL request struct */
 typedef struct H5VL_iod_request_t {
-    H5RQ_type_t type;
-    void *data;
-    void *req;
-    struct H5VL_iod_object_t *obj;
-    H5VL_iod_state_t state;
-    H5_status_t status;
-    uint64_t axe_id;
-    size_t num_parents;
-    struct H5VL_iod_request_t **parent_reqs;
-    struct H5VL_iod_request_t *prev;
-    struct H5VL_iod_request_t *next;
+    H5RQ_type_t type; /* The operation type of this request */
+    void *data; /* data associated with request (usually used at completion time) */
+    void *req; /* the request pointer correponding to the Mercury request */
+    struct H5VL_iod_object_t *obj; /* The object pointer that this request is associated with */
+    H5VL_iod_state_t state; /* current internal state of the request */
+    H5_status_t status; /* external status given to use of request */
+    uint64_t axe_id; /* The AXE ID this request was assigned */
+    unsigned ref_count; /* reference count to know when this request can be freed. */
+    H5VL_iod_req_info_t *trans_info; /* pointer to transaction or read context struct for this request */
+
+    size_t num_parents; /* Number of parents this request has (in AXE) */
+    struct H5VL_iod_request_t **parent_reqs; /* an array of the parent request pointers */
+
+    /* Linked list pointers for the container this request was generated. */
+    struct H5VL_iod_request_t *file_prev; 
+    struct H5VL_iod_request_t *file_next;
+
+    /* Linked list pointers for all IOD VOL requests in the library */
     struct H5VL_iod_request_t *global_prev;
     struct H5VL_iod_request_t *global_next;
-    unsigned ref_count;
+
+    /* Linked list pointers for the transaction this request belong to */
+    struct H5VL_iod_request_t *trans_prev;
+    struct H5VL_iod_request_t *trans_next;
 } H5VL_iod_request_t;
 
 /* struct that contains the information about the IOD container */
@@ -279,17 +289,16 @@ H5_DLL herr_t H5VL_iod_request_complete(H5VL_iod_file_t *file, H5VL_iod_request_
 H5_DLL herr_t H5VL_iod_request_cancel(H5VL_iod_file_t *file, H5VL_iod_request_t *req);
 H5_DLL herr_t H5VL_iod_request_decr_rc(H5VL_iod_request_t *request);
 
-H5_DLL herr_t H5VL_iod_get_parent_info(H5VL_iod_object_t *obj, H5VL_loc_params_t loc_params, 
-                                       const char *name, /*OUT*/iod_obj_id_t *iod_id, 
-                                       /*OUT*/iod_handle_t *iod_oh, 
-                                       /*OUT*/H5VL_iod_request_t **parent_req, 
-                                       /*OUT*/char **new_name, /*OUT*/H5VL_iod_object_t **last_obj);
-H5_DLL herr_t H5VL_iod_get_axe_parents(H5VL_iod_object_t *obj, /*IN/OUT*/ size_t *count, 
-                                       /*OUT*/ AXE_task_t *parent_axe_ids, 
-                                       /*OUT*/ H5VL_iod_request_t **parent_reqs);
+H5_DLL herr_t H5VL_iod_get_parent_requests(H5VL_iod_object_t *obj, H5VL_iod_req_info_t *req_info, 
+                                           H5VL_iod_request_t **parent_reqs, size_t *num_parents);
+H5_DLL  herr_t H5VL_iod_get_loc_info(H5VL_iod_object_t *obj, iod_obj_id_t *iod_id, 
+                                     iod_handle_t *iod_oh);
+H5_DLL herr_t H5VL_iod_get_obj_requests(H5VL_iod_object_t *obj, /*IN/OUT*/ size_t *count, 
+                                        /*OUT*/ H5VL_iod_request_t **parent_reqs);
 H5_DLL herr_t H5VL__iod_create_and_forward(hg_id_t op_id, H5RQ_type_t op_type, 
                                            H5VL_iod_object_t *request_obj, htri_t track,
                                            size_t num_parents, H5VL_iod_request_t **parent_reqs,
+                                           H5VL_iod_req_info_t *req_info,
                                            void *input, void *output, void *data, void **req);
 
 H5_DLL herr_t H5VL_iod_gen_obj_id(int myrank, int nranks, uint64_t cur_index, 
diff --git a/src/H5VLiod_common.h b/src/H5VLiod_common.h
index aa92625..628b358 100644
--- a/src/H5VLiod_common.h
+++ b/src/H5VLiod_common.h
@@ -105,13 +105,12 @@ MERCURY_GEN_PROC(file_open_out_t, ((iod_handle_t)(coh)) ((iod_handle_t)(root_oh)
                  ((uint64_t)(kv_oid_index)) ((uint64_t)(array_oid_index)) 
                  ((uint64_t)(blob_oid_index))
                  ((iod_obj_id_t)(root_id)) ((hid_t)(fcpl_id)))
-MERCURY_GEN_PROC(file_flush_in_t, ((axe_t)(axe_info)) 
-                 ((iod_handle_t)(coh)) ((int32_t)(scope)))
 MERCURY_GEN_PROC(file_close_in_t, ((axe_t)(axe_info)) 
                  ((iod_handle_t)(coh)) ((iod_handle_t)(root_oh))
                  ((iod_obj_id_t)(root_id)))
 
-MERCURY_GEN_PROC(attr_create_in_t, ((axe_t)(axe_info))
+MERCURY_GEN_PROC(attr_create_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) ((iod_obj_id_t)(attr_id))
                  ((hg_string_t)(path))
@@ -119,21 +118,25 @@ MERCURY_GEN_PROC(attr_create_in_t, ((axe_t)(axe_info))
                  ((hid_t)(type_id)) ((hid_t)(space_id)))
 MERCURY_GEN_PROC(attr_create_out_t, ((iod_handle_t)(iod_oh)))
 MERCURY_GEN_PROC(attr_open_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) ((hg_string_t)(path)) 
                  ((hg_string_t)(attr_name)))
 MERCURY_GEN_PROC(attr_open_out_t, ((iod_handle_t)(iod_oh)) ((iod_obj_id_t)(iod_id)) 
                  ((hid_t)(acpl_id)) ((hid_t)(type_id)) ((hid_t)(space_id)))
 MERCURY_GEN_PROC(attr_op_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) 
                  ((hg_string_t)(path)) ((hg_string_t)(attr_name)))
 MERCURY_GEN_PROC(attr_rename_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) 
                  ((hg_string_t)(path)) ((hg_string_t)(old_attr_name)) 
                  ((hg_string_t)(new_attr_name)))
 MERCURY_GEN_PROC(attr_io_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(iod_oh)) 
                  ((iod_obj_id_t)(iod_id))
                  ((hid_t)(type_id)) ((hg_bulk_t)(bulk_handle)))
@@ -141,12 +144,14 @@ MERCURY_GEN_PROC(attr_close_in_t, ((axe_t)(axe_info))
                  ((iod_handle_t)(iod_oh)) ((iod_obj_id_t)(iod_id)))
 
 MERCURY_GEN_PROC(group_create_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) ((iod_obj_id_t)(grp_id))
                  ((hg_string_t)(name)) ((hid_t)(gapl_id)) 
                  ((hid_t)(gcpl_id)) ((hid_t)(lcpl_id)))
 MERCURY_GEN_PROC(group_create_out_t, ((iod_handle_t)(iod_oh)))
 MERCURY_GEN_PROC(group_open_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) ((hg_string_t)(name))
                  ((hid_t)(gapl_id)))
@@ -156,6 +161,7 @@ MERCURY_GEN_PROC(group_close_in_t, ((axe_t)(axe_info))
                  ((iod_handle_t)(iod_oh)) ((iod_obj_id_t)(iod_id)))
 
 MERCURY_GEN_PROC(map_create_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) ((iod_obj_id_t)(map_id))
                  ((hg_string_t)(name)) 
@@ -164,18 +170,21 @@ MERCURY_GEN_PROC(map_create_in_t, ((axe_t)(axe_info))
                  ((hid_t)(lcpl_id)))
 MERCURY_GEN_PROC(map_create_out_t, ((iod_handle_t)(iod_oh)))
 MERCURY_GEN_PROC(map_open_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) 
                  ((hg_string_t)(name)) ((hid_t)(mapl_id)))
 MERCURY_GEN_PROC(map_open_out_t, ((iod_handle_t)(iod_oh)) ((iod_obj_id_t)(iod_id)) 
                  ((hid_t)(keytype_id)) ((hid_t)(valtype_id)) ((hid_t)(mcpl_id)))
 MERCURY_GEN_PROC(map_set_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(iod_oh))
                  ((iod_obj_id_t)(iod_id)) 
                  ((hid_t)(key_maptype_id)) ((hid_t)(key_memtype_id)) ((binary_buf_t)(key))
                  ((hid_t)(val_maptype_id)) ((hid_t)(val_memtype_id)) ((binary_buf_t)(val))
                  ((hid_t)(dxpl_id)))
 MERCURY_GEN_PROC(map_get_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(iod_oh))
                  ((iod_obj_id_t)(iod_id)) 
                  ((hid_t)(key_maptype_id)) ((hid_t)(key_memtype_id)) ((binary_buf_t)(key))
@@ -183,9 +192,11 @@ MERCURY_GEN_PROC(map_get_in_t, ((axe_t)(axe_info))
                  ((hid_t)(dxpl_id)))
 MERCURY_GEN_PROC(map_get_out_t, ((int32_t)(ret)) ((value_t)(val)))
 MERCURY_GEN_PROC(map_get_count_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(iod_oh))
                  ((iod_obj_id_t)(iod_id)))
 MERCURY_GEN_PROC(map_op_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(iod_oh))
                  ((iod_obj_id_t)(iod_id)) 
                  ((hid_t)(key_maptype_id)) ((hid_t)(key_memtype_id)) ((binary_buf_t)(key)))
@@ -193,6 +204,7 @@ MERCURY_GEN_PROC(map_close_in_t, ((axe_t)(axe_info))
                  ((iod_handle_t)(iod_oh)) ((iod_obj_id_t)(iod_id)))
 
 MERCURY_GEN_PROC(dset_create_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) ((iod_obj_id_t)(dset_id)) 
                  ((hg_string_t)(name))
@@ -200,21 +212,25 @@ MERCURY_GEN_PROC(dset_create_in_t, ((axe_t)(axe_info))
                  ((hid_t)(type_id)) ((hid_t)(space_id)))
 MERCURY_GEN_PROC(dset_create_out_t, ((iod_handle_t)(iod_oh)))
 MERCURY_GEN_PROC(dset_open_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) 
                  ((hg_string_t)(name)) ((hid_t)(dapl_id)))
 MERCURY_GEN_PROC(dset_open_out_t, ((iod_handle_t)(iod_oh)) ((iod_obj_id_t)(iod_id)) 
                  ((hid_t)(dcpl_id)) ((hid_t)(type_id)) ((hid_t)(space_id)))
 MERCURY_GEN_PROC(dset_set_extent_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(iod_oh)) 
                  ((iod_obj_id_t)(iod_id)) ((dims_t)(dims)))
 MERCURY_GEN_PROC(dset_io_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(iod_oh)) 
                  ((iod_obj_id_t)(iod_id))
                  ((hid_t)(dset_type_id)) ((hid_t)(mem_type_id))
                  ((hid_t)(space_id)) ((hid_t)(dxpl_id)) ((uint32_t)(checksum))
                  ((hg_bulk_t)(bulk_handle)))
 MERCURY_GEN_PROC(dset_get_vl_size_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(iod_oh)) 
                  ((iod_obj_id_t)(iod_id)) ((hid_t)(mem_type_id))
                  ((hid_t)(space_id)) ((hid_t)(dxpl_id)))
@@ -223,6 +239,7 @@ MERCURY_GEN_PROC(dset_close_in_t, ((axe_t)(axe_info))
                  ((iod_handle_t)(iod_oh)) ((iod_obj_id_t)(iod_id)))
 
 MERCURY_GEN_PROC(dtype_commit_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) ((iod_obj_id_t)(dtype_id)) 
                  ((hg_string_t)(name))
@@ -230,6 +247,7 @@ MERCURY_GEN_PROC(dtype_commit_in_t, ((axe_t)(axe_info))
                  ((hid_t)(type_id)))
 MERCURY_GEN_PROC(dtype_commit_out_t, ((iod_handle_t)(iod_oh)))
 MERCURY_GEN_PROC(dtype_open_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh))
                  ((iod_obj_id_t)(loc_id)) 
                  ((hg_string_t)(name)) ((hid_t)(tapl_id)))
@@ -239,6 +257,7 @@ MERCURY_GEN_PROC(dtype_close_in_t, ((axe_t)(axe_info))
                  ((iod_handle_t)(iod_oh)) ((iod_obj_id_t)(iod_id)))
 
 MERCURY_GEN_PROC(link_create_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((int8_t)(create_type)) ((iod_handle_t)(coh)) 
                  ((iod_handle_t)(loc_oh)) ((iod_obj_id_t)(loc_id))
                  ((hg_string_t)(loc_name))
@@ -247,6 +266,7 @@ MERCURY_GEN_PROC(link_create_in_t, ((axe_t)(axe_info))
                  ((hg_string_t)(link_value))
                  ((hid_t)(lapl_id)) ((hid_t)(lcpl_id)))
 MERCURY_GEN_PROC(link_move_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((hbool_t)(copy_flag)) ((iod_handle_t)(coh)) 
                  ((iod_handle_t)(src_loc_oh)) ((iod_obj_id_t)(src_loc_id))
                  ((hg_string_t)(src_loc_name))
@@ -254,16 +274,19 @@ MERCURY_GEN_PROC(link_move_in_t, ((axe_t)(axe_info))
                  ((hg_string_t)(dst_loc_name))
                  ((hid_t)(lapl_id)) ((hid_t)(lcpl_id)))
 MERCURY_GEN_PROC(link_op_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh)) 
                  ((iod_obj_id_t)(loc_id)) 
                  ((hg_string_t)(path)))
 MERCURY_GEN_PROC(link_get_val_in_t, ((axe_t)(axe_info))
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh)) 
                  ((iod_obj_id_t)(loc_id)) 
                  ((hg_string_t)(path)) ((uint64_t)(length)))
 MERCURY_GEN_PROC(link_get_val_out_t, ((int32_t)(ret)) ((value_t)(value)))
 
 MERCURY_GEN_PROC(object_op_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh)) 
                  ((iod_obj_id_t)(loc_id)) 
                  ((hg_string_t)(loc_name)))
@@ -271,6 +294,7 @@ MERCURY_GEN_PROC(object_open_out_t, ((int32_t)(obj_type))
                  ((iod_handle_t)(iod_oh)) ((iod_obj_id_t)(iod_id)) 
                  ((hid_t)(cpl_id)) ((hid_t)(type_id)) ((hid_t)(space_id)))
 MERCURY_GEN_PROC(object_copy_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) 
                  ((iod_handle_t)(src_loc_oh)) ((iod_obj_id_t)(src_loc_id))
                  ((hg_string_t)(src_loc_name))
@@ -278,10 +302,12 @@ MERCURY_GEN_PROC(object_copy_in_t, ((axe_t)(axe_info))
                  ((hg_string_t)(dst_loc_name))
                  ((hid_t)(ocpypl_id)) ((hid_t)(lcpl_id)))
 MERCURY_GEN_PROC(object_set_comment_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num)) ((uint64_t)(trans_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh)) 
                  ((iod_obj_id_t)(loc_id)) 
                  ((hg_string_t)(path)) ((hg_string_t)(comment)))
 MERCURY_GEN_PROC(object_get_comment_in_t, ((axe_t)(axe_info)) 
+                 ((uint64_t)(rcxt_num))
                  ((iod_handle_t)(coh)) ((iod_handle_t)(loc_oh)) 
                  ((iod_obj_id_t)(loc_id))
                  ((hg_string_t)(path)) ((uint64_t)(length)))
diff --git a/src/H5VLiod_dset.c b/src/H5VLiod_dset.c
index fcb6455..bf35869 100644
--- a/src/H5VLiod_dset.c
+++ b/src/H5VLiod_dset.c
@@ -90,6 +90,8 @@ H5VL_iod_server_dset_create_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t loc_handle = input->loc_oh; /* location handle to start lookup */
     iod_obj_id_t loc_id = input->loc_id; /* The ID of the current location object */
     iod_obj_id_t dset_id = input->dset_id; /* The ID of the dataset that needs to be created */
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t dset_oh, cur_oh, mdkv_oh;
     iod_obj_id_t cur_id, mdkv_id, attr_id;
     const char *name = input->name; /* name of dset including path to create */
@@ -282,6 +284,7 @@ H5VL_iod_server_dset_open_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t coh = input->coh; /* container handle */
     iod_handle_t loc_handle = input->loc_oh; /* location handle to start lookup */
     iod_obj_id_t loc_id = input->loc_id; /* The ID of the current location object */
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_obj_id_t dset_id; /* ID of the dataset to open */
     iod_handle_t dset_oh, mdkv_oh;
     const char *name = input->name; /* name of dset including path to open */
@@ -432,6 +435,7 @@ H5VL_iod_server_dset_read_cb(AXE_engine_t UNUSED axe_engine,
     hid_t dxpl_id = input->dxpl_id; /* transfer property list */
     hid_t src_id = input->dset_type_id; /* the datatype of the dataset's element */
     hid_t dst_id = input->mem_type_id; /* the memory type of the elements */
+    iod_trans_id_t rtid = input->rcxt_num;
     hg_bulk_block_t bulk_block_handle; /* HG block handle */
     hg_bulk_request_t bulk_request; /* HG request */
     size_t size, buf_size;
@@ -646,6 +650,7 @@ H5VL_iod_server_dset_get_vl_size_cb(AXE_engine_t UNUSED axe_engine,
     iod_obj_id_t iod_id = input->iod_id; /* dset ID */
     hid_t space_id = input->space_id; /* file space selection */
     hid_t dxpl_id = input->dxpl_id; /* transfer property list */
+    iod_trans_id_t rtid = input->rcxt_num;
     size_t buf_size;
     void *buf = NULL; /* buffer to hold blob IDs */
     size_t nelmts; /* number of elements selected to read */
@@ -854,6 +859,8 @@ H5VL_iod_server_dset_write_cb(AXE_engine_t UNUSED axe_engine,
     uint32_t cs = input->checksum; /* checksum recieved for data */
     hid_t src_id = input->mem_type_id; /* the memory type of the elements */
     hid_t dst_id = input->dset_type_id; /* the datatype of the dataset's element */
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     hg_bulk_block_t bulk_block_handle; /* HG block handle */
     hg_bulk_request_t bulk_request; /* HG request */
     size_t size, buf_size;
@@ -1031,6 +1038,8 @@ H5VL_iod_server_dset_set_extent_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t coh = input->coh;
     iod_handle_t iod_oh = input->iod_oh;
     iod_obj_id_t iod_id = input->iod_id; 
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     /* int rank = input->dims.rank;  rank of dataset */
     hbool_t opened_locally = FALSE;
     herr_t ret_value = SUCCEED;
diff --git a/src/H5VLiod_dtype.c b/src/H5VLiod_dtype.c
index f102171..3c6ac58 100644
--- a/src/H5VLiod_dtype.c
+++ b/src/H5VLiod_dtype.c
@@ -51,6 +51,8 @@ H5VL_iod_server_dtype_commit_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t loc_handle = input->loc_oh; /* location handle to start lookup */
     iod_obj_id_t loc_id = input->loc_id; /* The ID of the current location object */
     iod_obj_id_t dtype_id = input->dtype_id; /* The ID of the datatype that needs to be created */
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t dtype_oh, cur_oh, mdkv_oh;
     iod_obj_id_t cur_id, mdkv_id, attr_id;
     const char *name = input->name; /* name of dtype including path to commit */
@@ -256,6 +258,7 @@ H5VL_iod_server_dtype_open_cb(AXE_engine_t UNUSED axe_engine,
     iod_obj_id_t dtype_id; /* ID of datatype to open */
     iod_handle_t dtype_oh, mdkv_oh;
     const char *name = input->name; /* name of dtype including path to open */
+    iod_trans_id_t rtid = input->rcxt_num;
     size_t buf_size; /* size of serialized datatype */
     void *buf = NULL;
     iod_mem_desc_t *mem_desc = NULL; /* memory descriptor used for reading */
diff --git a/src/H5VLiod_file.c b/src/H5VLiod_file.c
index 4a37b2f..ca44f02 100644
--- a/src/H5VLiod_file.c
+++ b/src/H5VLiod_file.c
@@ -55,6 +55,7 @@ H5VL_iod_server_file_create_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t mdkv_oh; /* metadata object handle for KV to store file's metadata */
     iod_obj_id_t mdkv_id, attr_id; /* metadata and attribute KV IDs for the file */
     iod_ret_t ret;
+    iod_trans_id_t first_tid = 0;
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -73,7 +74,7 @@ H5VL_iod_server_file_create_cb(AXE_engine_t UNUSED axe_engine,
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "can't create container");
 
     /* create the root group */
-    ret = iod_obj_create(coh, IOD_TID_UNKNOWN, NULL, IOD_OBJ_KV, NULL, NULL, 
+    ret = iod_obj_create(coh, first_tid, NULL, IOD_OBJ_KV, NULL, NULL, 
                          &input->root_id, NULL);
     if(0 == ret || EEXISTS == ret) {
         /* root group has been created, open it */
@@ -94,12 +95,12 @@ H5VL_iod_server_file_create_cb(AXE_engine_t UNUSED axe_engine,
         hid_t fcpl_id;
 
         /* create the metadata KV object for the root group */
-        if(iod_obj_create(coh, IOD_TID_UNKNOWN, NULL, IOD_OBJ_KV, 
+        if(iod_obj_create(coh, first_tid, NULL, IOD_OBJ_KV, 
                           NULL, NULL, &mdkv_id, NULL) < 0)
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't create metadata KV object");
 
         /* create the attribute KV object for the root group */
-        if(iod_obj_create(coh, IOD_TID_UNKNOWN, NULL, IOD_OBJ_KV, 
+        if(iod_obj_create(coh, first_tid, NULL, IOD_OBJ_KV, 
                           NULL, NULL, &attr_id, NULL) < 0)
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't create metadata KV object");
 
@@ -110,7 +111,7 @@ H5VL_iod_server_file_create_cb(AXE_engine_t UNUSED axe_engine,
         sp.filler2_id = IOD_ID_UNDEFINED;
 
         /* set scratch pad in root group */
-        if (iod_obj_set_scratch(root_oh, IOD_TID_UNKNOWN, &sp, NULL, NULL) < 0)
+        if (iod_obj_set_scratch(root_oh, first_tid, &sp, NULL, NULL) < 0)
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't set scratch pad");
 
         /* Store Metadata in scratch pad */
@@ -125,7 +126,7 @@ H5VL_iod_server_file_create_cb(AXE_engine_t UNUSED axe_engine,
         fcpl_id = input->fcpl_id;
 
         /* insert plist metadata */
-        if(H5VL_iod_insert_plist(mdkv_oh, IOD_TID_UNKNOWN, fcpl_id, 
+        if(H5VL_iod_insert_plist(mdkv_oh, first_tid, fcpl_id, 
                                  NULL, NULL, NULL) < 0)
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't insert link count KV value");
 
@@ -137,21 +138,21 @@ H5VL_iod_server_file_create_cb(AXE_engine_t UNUSED axe_engine,
 
         key = strdup(H5VL_IOD_KEY_KV_IDS_INDEX);
         kv.key = (char *)key;
-        if (iod_kv_set(mdkv_oh, IOD_TID_UNKNOWN, NULL, &kv, NULL, NULL) < 0)
+        if (iod_kv_set(mdkv_oh, first_tid, NULL, &kv, NULL, NULL) < 0)
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't set KV pair in parent");
         free(key); 
         key = NULL;
 
         key = strdup(H5VL_IOD_KEY_ARRAY_IDS_INDEX);
         kv.key = (char *)key;
-        if (iod_kv_set(mdkv_oh, IOD_TID_UNKNOWN, NULL, &kv, NULL, NULL) < 0)
+        if (iod_kv_set(mdkv_oh, first_tid, NULL, &kv, NULL, NULL) < 0)
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't set KV pair in parent");
         free(key); 
         key = NULL;
 
         key = strdup(H5VL_IOD_KEY_BLOB_IDS_INDEX);
         kv.key = (char *)key;
-        if (iod_kv_set(mdkv_oh, IOD_TID_UNKNOWN, NULL, &kv, NULL, NULL) < 0)
+        if (iod_kv_set(mdkv_oh, first_tid, NULL, &kv, NULL, NULL) < 0)
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't set KV pair in parent");
         free(key); 
         key = NULL;
@@ -320,50 +321,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5VL_iod_server_file_flush_cb
- *
- * Purpose:	Flushs iod HDF5 file.
- *
- * Return:	Success:	SUCCEED 
- *		Failure:	Negative
- *
- * Programmer:  Mohamad Chaarawi
- *              January, 2013
- *
- *-------------------------------------------------------------------------
- */
-void
-H5VL_iod_server_file_flush_cb(AXE_engine_t UNUSED axe_engine, 
-                              size_t UNUSED num_n_parents, AXE_task_t UNUSED n_parents[], 
-                              size_t UNUSED num_s_parents, AXE_task_t UNUSED s_parents[], 
-                              void *_op_data)
-{
-    op_data_t *op_data = (op_data_t *)_op_data;
-    file_flush_in_t *input = (file_flush_in_t *)op_data->input;
-    iod_handle_t coh = input->coh;
-    H5F_scope_t scope = input->scope;
-    herr_t ret_value = SUCCEED;
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    /* MSC - TODO */
-
-#if H5_DO_NATIVE
-    ret_value = H5Fflush(coh.cookie, scope);
-#endif
-
-done:
-    if(HG_SUCCESS != HG_Handler_start_output(op_data->hg_handle, &ret_value))
-        HDONE_ERROR(H5E_SYM, H5E_CANTDEC, FAIL, "can't send result of file flush to client");
-
-    input = (file_flush_in_t *)H5MM_xfree(input);
-    op_data = (op_data_t *)H5MM_xfree(op_data);
-
-    FUNC_LEAVE_NOAPI_VOID
-} /* end H5VL_iod_server_file_flush_cb() */
-
-
-/*-------------------------------------------------------------------------
  * Function:	H5VL_iod_server_file_close_cb
  *
  * Purpose:	Closes iod HDF5 file.
diff --git a/src/H5VLiod_group.c b/src/H5VLiod_group.c
index b40d180..89d202d 100644
--- a/src/H5VLiod_group.c
+++ b/src/H5VLiod_group.c
@@ -54,6 +54,8 @@ H5VL_iod_server_group_create_cb(AXE_engine_t UNUSED axe_engine,
     iod_obj_id_t loc_id = input->loc_id; /* The ID of the current location object */
     iod_obj_id_t grp_id = input->grp_id; /* The ID of the group that needs to be created */
     const char *name = input->name; /* path relative to loc_id and loc_oh  */
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t grp_oh, cur_oh, mdkv_oh;
     iod_obj_id_t cur_id, mdkv_id, attr_id;
     char *last_comp = NULL; /* the name of the group obtained from traversal function */
@@ -207,6 +209,7 @@ H5VL_iod_server_group_open_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t loc_handle = input->loc_oh; /* location handle to start lookup */
     iod_obj_id_t loc_id = input->loc_id; /* The ID of the current location object */
     const char *name = input->name; /* group name including path to open */
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_obj_id_t grp_id; /* The ID of the group that needs to be opened */
     iod_handle_t grp_oh, mdkv_oh; /* The group handle and its metadata KV handle */
     scratch_pad_t sp;
diff --git a/src/H5VLiod_link.c b/src/H5VLiod_link.c
index 21f9e20..fb8c89c 100644
--- a/src/H5VLiod_link.c
+++ b/src/H5VLiod_link.c
@@ -48,6 +48,8 @@ H5VL_iod_server_link_create_cb(AXE_engine_t UNUSED axe_engine,
     link_create_in_t *input = (link_create_in_t *)op_data->input;
     H5VL_link_create_type_t create_type = input->create_type;
     iod_handle_t coh = input->coh; /* the container handle */
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t src_oh; /* The handle for creation src object */
     iod_obj_id_t src_id; /* The ID of the creation src object */
     iod_handle_t target_oh;
@@ -191,6 +193,8 @@ H5VL_iod_server_link_move_cb(AXE_engine_t UNUSED axe_engine,
     link_move_in_t *input = (link_move_in_t *)op_data->input;
     hbool_t copy_flag = input->copy_flag;
     iod_handle_t coh = input->coh; /* the container handle */
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t src_oh; /* The handle for src object group */
     iod_obj_id_t src_id; /* The ID of the src object */
     iod_handle_t dst_oh; /* The handle for the dst object where link is created*/
@@ -366,6 +370,7 @@ H5VL_iod_server_link_exists_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t cur_oh;
     iod_obj_id_t cur_id;
     const char *loc_name = input->path;
+    iod_trans_id_t rtid = input->rcxt_num;
     char *last_comp = NULL;
     htri_t ret = -1;
     iod_size_t kv_size = 0;
@@ -450,6 +455,7 @@ H5VL_iod_server_link_get_info_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t cur_oh;
     iod_obj_id_t cur_id;
     const char *loc_name = input->path;
+    iod_trans_id_t rtid = input->rcxt_num;
     char *last_comp = NULL;
     H5VL_iod_link_t iod_link;
     herr_t ret_value = SUCCEED;
@@ -549,6 +555,7 @@ H5VL_iod_server_link_get_val_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t loc_oh = input->loc_oh;
     iod_obj_id_t loc_id = input->loc_id;
     size_t length = input->length;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t cur_oh;
     iod_obj_id_t cur_id;
     const char *loc_name = input->path;
@@ -646,6 +653,8 @@ H5VL_iod_server_link_remove_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t coh = input->coh;
     iod_handle_t loc_oh = input->loc_oh;
     iod_obj_id_t loc_id = input->loc_id;
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t cur_oh;
     iod_obj_id_t cur_id;
     const char *loc_name = input->path;
diff --git a/src/H5VLiod_map.c b/src/H5VLiod_map.c
index b413faf..f49260f 100644
--- a/src/H5VLiod_map.c
+++ b/src/H5VLiod_map.c
@@ -56,6 +56,8 @@ H5VL_iod_server_map_create_cb(AXE_engine_t UNUSED axe_engine,
     const char *name = input->name; /* path relative to loc_id and loc_oh  */
     hid_t keytype = input->keytype_id;
     hid_t valtype = input->valtype_id;
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t map_oh, cur_oh, mdkv_oh;
     iod_obj_id_t cur_id, mdkv_id, attr_id;
     char *last_comp; /* the name of the group obtained from traversal function */
@@ -205,6 +207,7 @@ H5VL_iod_server_map_open_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t loc_handle = input->loc_oh;
     iod_obj_id_t loc_id = input->loc_id;
     const char *name = input->name;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_obj_id_t map_id; /* The ID of the map that needs to be opened */
     iod_handle_t map_oh, mdkv_oh;
     scratch_pad_t sp;
@@ -311,6 +314,8 @@ H5VL_iod_server_map_set_cb(AXE_engine_t UNUSED axe_engine,
     binary_buf_t key = input->key;
     binary_buf_t val = input->val;
     hid_t dxpl_id = input->dxpl_id;
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_size_t key_size, val_size;
     size_t src_size, dst_size;
     void *key_buf = NULL, *val_buf = NULL;
@@ -432,6 +437,7 @@ H5VL_iod_server_map_get_cb(AXE_engine_t UNUSED axe_engine,
     hid_t val_maptype_id = input->val_maptype_id;
     binary_buf_t key = input->key;
     hid_t dxpl_id = input->dxpl_id;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_size_t key_size, val_size;
     size_t src_size, dst_size;
     void *key_buf = NULL, *val_buf = NULL;
@@ -557,7 +563,8 @@ H5VL_iod_server_map_get_count_cb(AXE_engine_t UNUSED axe_engine,
     map_get_count_in_t *input = (map_get_count_in_t *)op_data->input;
     iod_handle_t coh = input->coh;
     iod_handle_t iod_oh = input->iod_oh;
-    iod_obj_id_t iod_id = input->iod_id; 
+    iod_obj_id_t iod_id = input->iod_id;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_size_t num;
     hbool_t opened_locally = FALSE;
     herr_t ret_value = SUCCEED;
@@ -636,6 +643,7 @@ H5VL_iod_server_map_exists_cb(AXE_engine_t UNUSED axe_engine,
     hid_t key_memtype_id = input->key_memtype_id;
     hid_t key_maptype_id = input->key_maptype_id;
     binary_buf_t key = input->key;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_size_t key_size, val_size;
     size_t src_size, dst_size;
     void *key_buf = NULL;
@@ -738,6 +746,8 @@ H5VL_iod_server_map_delete_cb(AXE_engine_t UNUSED axe_engine,
     hid_t key_memtype_id = input->key_memtype_id;
     hid_t key_maptype_id = input->key_maptype_id;
     binary_buf_t key = input->key;
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_size_t key_size;
     size_t src_size, dst_size;
     void *key_buf = NULL;
diff --git a/src/H5VLiod_obj.c b/src/H5VLiod_obj.c
index 3c1e8b9..83a618a 100644
--- a/src/H5VLiod_obj.c
+++ b/src/H5VLiod_obj.c
@@ -48,6 +48,7 @@ H5VL_iod_server_object_open_cb(AXE_engine_t UNUSED axe_engine,
     object_op_in_t *input = (object_op_in_t *)op_data->input;
     object_open_out_t output;
     iod_handle_t coh = input->coh; /* the container handle */
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t obj_oh; /* The handle for object */
     iod_obj_id_t obj_id; /* The ID of the object */
     iod_handle_t mdkv_oh;
@@ -244,6 +245,8 @@ H5VL_iod_server_object_copy_cb(AXE_engine_t UNUSED axe_engine,
     op_data_t *op_data = (op_data_t *)_op_data;
     object_copy_in_t *input = (object_copy_in_t *)op_data->input;
     iod_handle_t coh = input->coh; /* the container handle */
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t dst_oh; /* The handle for the dst object where link is created*/
     iod_obj_id_t dst_id; /* The ID of the dst object where link is created*/
     iod_obj_id_t obj_id; /* The ID of the object to be moved/copied */
@@ -419,6 +422,7 @@ H5VL_iod_server_object_exists_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t coh = input->coh;
     iod_handle_t loc_oh = input->loc_oh;
     iod_obj_id_t loc_id = input->loc_id;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t obj_oh;
     iod_obj_id_t obj_id;
     const char *loc_name = input->loc_name;
@@ -488,6 +492,7 @@ H5VL_iod_server_object_get_info_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t coh = input->coh;
     iod_handle_t loc_oh = input->loc_oh;
     iod_obj_id_t loc_id = input->loc_id;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t obj_oh, mdkv_oh, attrkv_oh;
     iod_obj_id_t obj_id;
     scratch_pad_t sp;
@@ -613,6 +618,8 @@ H5VL_iod_server_object_set_comment_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t coh = input->coh;
     iod_handle_t loc_oh = input->loc_oh;
     iod_obj_id_t loc_id = input->loc_id;
+    iod_trans_id_t wtid = input->trans_num;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t obj_oh, mdkv_oh;
     iod_obj_id_t obj_id;
     const char *loc_name = input->path;
@@ -703,6 +710,7 @@ H5VL_iod_server_object_get_comment_cb(AXE_engine_t UNUSED axe_engine,
     iod_handle_t loc_oh = input->loc_oh;
     iod_obj_id_t loc_id = input->loc_id;
     size_t length = input->length;
+    iod_trans_id_t rtid = input->rcxt_num;
     iod_handle_t obj_oh, mdkv_oh;
     iod_obj_id_t obj_id;
     const char *loc_name = input->path;
diff --git a/src/H5VLiod_server.c b/src/H5VLiod_server.c
index 77fba12..9bcbc5d 100644
--- a/src/H5VLiod_server.c
+++ b/src/H5VLiod_server.c
@@ -60,8 +60,6 @@ H5VLiod_start_handler(MPI_Comm comm, MPI_Info UNUSED info)
                              file_create_in_t, file_create_out_t);
     MERCURY_HANDLER_REGISTER("file_open", H5VL_iod_server_file_open, 
                              file_open_in_t, file_open_out_t);
-    MERCURY_HANDLER_REGISTER("file_flush", H5VL_iod_server_file_flush, 
-                             file_flush_in_t, ret_t);
     MERCURY_HANDLER_REGISTER("file_close", H5VL_iod_server_file_close, 
                              file_close_in_t, ret_t);
 
@@ -463,58 +461,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5VL_iod_server_file_flush
- *
- * Purpose:	Function shipper registered call for File Flush.
- *              Inserts the real worker routine into the Async Engine.
- *
- * Return:	Success:	HG_SUCCESS 
- *		Failure:	Negative
- *
- * Programmer:  Mohamad Chaarawi
- *              January, 2013
- *
- *-------------------------------------------------------------------------
- */
-int
-H5VL_iod_server_file_flush(hg_handle_t handle)
-{
-    op_data_t *op_data = NULL;
-    file_flush_in_t *input = NULL;
-    int ret_value = HG_SUCCESS;
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    if(NULL == (op_data = (op_data_t *)H5MM_malloc(sizeof(op_data_t))))
-	HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, HG_FAIL, "can't allocate axe op_data struct");
-
-    if(NULL == (input = (file_flush_in_t *) H5MM_malloc(sizeof(file_flush_in_t))))
-	HGOTO_ERROR(H5E_FILE, H5E_NOSPACE, HG_FAIL, "can't allocate input struct for decoding");
-
-    if(HG_FAIL == HG_Handler_get_input(handle, input))
-	HGOTO_ERROR(H5E_FILE, H5E_CANTGET, HG_FAIL, "can't get input parameters");
-
-    if(NULL == engine)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, HG_FAIL, "AXE engine not started");
-
-    if(input->axe_info.count && 
-       H5VL__iod_server_finish_axe_tasks(engine, input->axe_info.start_range,  
-                                         input->axe_info.count) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, HG_FAIL, "Unable to cleanup AXE tasks");
-
-    op_data->hg_handle = handle;
-    op_data->input = (void *)input;
-
-    if (AXE_SUCCEED != AXEcreate_barrier_task(engine, input->axe_info.axe_id,
-                                              H5VL_iod_server_file_flush_cb, op_data, NULL))
-        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, HG_FAIL, "can't insert task into async engine");
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5VL_iod_server_file_flush() */
-
-
-/*-------------------------------------------------------------------------
  * Function:	H5VL_iod_server_file_close
  *
  * Purpose:	Function shipper registered call for File Close.
diff --git a/src/H5VLiod_server.h b/src/H5VLiod_server.h
index 435b0e5..1207abc 100644
--- a/src/H5VLiod_server.h
+++ b/src/H5VLiod_server.h
@@ -81,7 +81,6 @@ H5_DLL int H5VL_iod_server_eff_init(hg_handle_t handle);
 H5_DLL int H5VL_iod_server_eff_finalize(hg_handle_t handle);
 H5_DLL int H5VL_iod_server_file_create(hg_handle_t handle);
 H5_DLL int H5VL_iod_server_file_open(hg_handle_t handle);
-H5_DLL int H5VL_iod_server_file_flush(hg_handle_t handle);
 H5_DLL int H5VL_iod_server_file_close(hg_handle_t handle);
 H5_DLL int H5VL_iod_server_attr_create(hg_handle_t handle);
 H5_DLL int H5VL_iod_server_attr_open(hg_handle_t handle);
@@ -149,10 +148,6 @@ H5_DLL void H5VL_iod_server_file_close_cb(AXE_engine_t axe_engine,
                                           size_t num_n_parents, AXE_task_t n_parents[], 
                                           size_t num_s_parents, AXE_task_t s_parents[], 
                                           void *op_data);
-H5_DLL void H5VL_iod_server_file_flush_cb(AXE_engine_t axe_engine,  
-                                          size_t num_n_parents, AXE_task_t n_parents[], 
-                                          size_t num_s_parents, AXE_task_t s_parents[], 
-                                          void *op_data);
 H5_DLL void H5VL_iod_server_attr_create_cb(AXE_engine_t axe_engine,  
                                            size_t num_n_parents, AXE_task_t n_parents[], 
                                            size_t num_s_parents, AXE_task_t s_parents[], 
diff --git a/src/H5VLiod_trans.c b/src/H5VLiod_trans.c
index 49c87bc..3ea59e5 100644
--- a/src/H5VLiod_trans.c
+++ b/src/H5VLiod_trans.c
@@ -109,6 +109,40 @@ H5VL_iod_server_rcxt_acquire_cb(AXE_engine_t UNUSED axe_engine,
             }
             break;
         }
+    case H5RC_PREV:
+        {
+            iod_container_tids_t tids;
+            uint64_t u;
+
+#if H5VL_IOD_DEBUG
+            fprintf(stderr, "Next Acquire Read Context %llu\n", input->c_version);
+#endif
+            if(iod_container_query_tids(coh, &tids, NULL) < 0)
+                HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get container tids status");
+
+            if(c_version >= tids.latest_rdable) {
+                acquired_version = tids.latest_rdable;
+                if(iod_trans_start(coh, &acquired_version, NULL, 0, IOD_TRANS_RD, NULL) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't acquire read context");
+                break;
+            }
+
+            acquired_version = IOD_TID_UNKNOWN;
+            u=c_version;
+
+            for(u=c_version; u>=0; u--) {
+                if(iod_trans_start(coh, &u, NULL, 0, IOD_TRANS_RD, NULL) < 0)
+                    continue;
+                acquired_version = u;
+                break;
+            }
+
+            if(IOD_TID_UNKNOWN == acquired_version) {
+                HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, 
+                            "can't get a read version before %llu\n", c_version);
+            }
+            break;
+        }
     default:
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "invalid acquire request");
     }
-- 
cgit v0.12