Third batch of checkin:

1) Free space manager for the metadata file
2) Delayed free space release linked list
3) H5F_update_vfd_swmr_metadata_file()
3) VFD SWMR driver: read callback
4) Flushing for VFD SWMR
5) Port one concurrent test from swmr test set
6) Bug fixes and refactoring

7 files changed, 2125 insertions, 1 deletions

diff --git a/test/Makefile.am b/test/Makefile.am
index bcb50ec..9558e0f 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -33,10 +33,12 @@ AM_CPPFLAGS+=-I$(top_srcdir)/src -I$(top_builddir)/src
 #       test_filter_plugin.sh: filter_plugin.c
 #       test_usecases.sh: use_append_chunk, use_append_mchunks, use_disable_mdc_flushes
 TEST_SCRIPT = testerror.sh testlibinfo.sh testcheck_version.sh testlinks_env.sh test_filenotclosed.sh\
-    testswmr.sh testvdsswmr.sh testflushrefresh.sh test_usecases.sh
+    testswmr.sh testvdsswmr.sh testflushrefresh.sh test_usecases.sh \
+    testvfdswmr.sh
 SCRIPT_DEPEND = error_test$(EXEEXT) err_compat$(EXEEXT) links_env$(EXEEXT) filenotclosed$(EXEEXT) \
     flushrefresh$(EXEEXT) use_append_chunk$(EXEEXT) use_append_mchunks$(EXEEXT) use_disable_mdc_flushes$(EXEEXT) \
     swmr_generator$(EXEEXT) swmr_reader$(EXEEXT) swmr_writer$(EXEEXT) \
+    vfd_swmr_generator$(EXEEXT) vfd_swmr_writer$(EXEEXT) vfd_swmr_reader$(EXEEXT)  \
     swmr_remove_reader$(EXEEXT) swmr_remove_writer$(EXEEXT) swmr_addrem_writer$(EXEEXT) \
     swmr_sparse_reader$(EXEEXT) swmr_sparse_writer$(EXEEXT) swmr_start_write$(EXEEXT) \
     vds_swmr_gen$(EXEEXT) vds_swmr_reader$(EXEEXT) vds_swmr_writer$(EXEEXT)
@@ -80,6 +82,7 @@ check_PROGRAMS=$(TEST_PROG) error_test err_compat tcheck_version \
     testmeta accum_swmr_reader atomic_writer atomic_reader \
     links_env filenotclosed flushrefresh use_append_chunk use_append_mchunks use_disable_mdc_flushes \
     swmr_generator swmr_start_write swmr_reader swmr_writer swmr_remove_reader \
+    vfd_swmr_generator vfd_swmr_reader vfd_swmr_writer \
     swmr_remove_writer swmr_addrem_writer swmr_sparse_reader swmr_sparse_writer \
     swmr_check_compat_vfd vds_swmr_gen vds_swmr_reader vds_swmr_writer
 if HAVE_SHARED_CONDITIONAL
diff --git a/test/testvfdswmr.sh.in b/test/testvfdswmr.sh.in
new file mode 100644
index 0000000..a0b5aee
--- /dev/null
+++ b/test/testvfdswmr.sh.in
@@ -0,0 +1,292 @@
+#! /bin/bash
+#
+# Copyright by The HDF Group.
+# Copyright by the Board of Trustees of the University of Illinois.
+# All rights reserved.
+#
+# This file is part of HDF5.  The full HDF5 copyright notice, including
+# terms governing use, modification, and redistribution, is contained in
+# the COPYING file, which can be found at the root of the source code
+# distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.
+# If you do not have access to either file, you may request a copy from
+# help@hdfgroup.org.
+#
+# Tests for the vfd swmr feature.
+#
+###############################################################################
+# Copied current SWMR concurrent tests and renamed to:
+#   testswmr.sh.in-->test_vfd_swmr.sh.in
+#   swmr_generator.c-->vfd_swmr_generator.c
+#   swmr_reader.c-->vfd_swmr_reader.c
+#   swmr_writer.c-->vfd_swmr_writer.c
+#
+# FOR NOW: only one test is copied
+###############################################################################
+
+srcdir=@srcdir@
+
+###############################################################################
+## test parameters
+###############################################################################
+
+Nreaders=1              # number of readers to launch
+Nrdrs_spa=3             # number of sparse readers to launch
+Nrecords=200000         # number of records to write
+Nrecs_rem=40000         # number of times to shrink
+Nrecs_spa=20000         # number of records to write in the sparse test
+Nsecs_add=5             # number of seconds per read interval
+Nsecs_rem=3             # number of seconds per read interval
+Nsecs_addrem=8          # number of seconds per read interval
+nerrors=0
+
+###############################################################################
+## definitions for message file to coordinate test runs
+###############################################################################
+WRITER_MESSAGE=SWMR_WRITER_MESSAGE      # The message file created by writer that the open is complete
+                                        # This should be the same as the define in "./swmr_common.h"
+MESSAGE_TIMEOUT=300                     # Message timeout length in secs
+                                        # This should be the same as the define in "./h5test.h"
+
+###############################################################################
+## short hands and function definitions
+###############################################################################
+##DPRINT=:              # Set to "echo Debug:" for debugging printing,
+DPRINT="echo Debug:"    # Set to "echo Debug:" for debugging printing,
+                        # else ":" for noop.
+##IFDEBUG=:             # Set to null to turn on debugging, else ":" for noop.
+IFDEBUG=                # Set to null to turn on debugging, else ":" for noop.
+
+# Print a line-line message left justified in a field of 70 characters
+# beginning with the word "Testing".
+#
+TESTING() {
+   SPACES="                                                               "
+   echo "Testing $* $SPACES" | cut -c1-70 | tr -d '\012'
+}
+
+# To wait for the writer message file or till the maximum # of seconds is reached
+# $1 is the message file to wait for
+# This performs similar function as the routine h5_wait_message() in test/h5test.c
+WAIT_MESSAGE() {
+    message=$1                                  # Get the name of the message file to wait for
+    t0=`date +%s`                               # Get current time in seconds
+    difft=0                                     # Initialize the time difference
+    mexist=0                                    # Indicate whether the message file is found
+    while [ $difft -lt $MESSAGE_TIMEOUT ] ;     # Loop till message times out
+    do
+        t1=`date +%s`                           # Get current time in seconds
+        difft=`expr $t1 - $t0`                  # Calculate the time difference
+        if [ -e $message ]; then                # If message file is found:
+            mexist=1                            #       indicate the message file is found
+            rm $message                         #       remove the message file
+            break                               #       get out of the while loop
+        fi
+    done;
+    if test $mexist -eq 0; then
+        # Issue warning that the writer message file is not found, continue with launching the reader(s)
+        echo warning: $WRITER_MESSAGE is not found after waiting $MESSAGE_TIMEOUT seconds
+    else
+        echo $WRITER_MESSAGE is found
+    fi
+}
+
+###############################################################################
+## Main
+##
+## Modifications:
+##   Vailin Choi; July 2013
+##     Add waiting of message file before launching the reader(s).
+##     Due to the implementation of file locking, coordination
+##     is needed in file opening for the writer/reader tests
+##     to proceed as expected.
+##
+###############################################################################
+# The build (current) directory might be different than the source directory.
+if test -z "$srcdir"; then
+   srcdir=.
+fi
+
+# Check to see if the VFD specified by the HDF5_DRIVER environment variable
+# supports SWMR.
+./swmr_check_compat_vfd
+rc=$?
+if [ $rc -ne 0 ] ; then
+    echo
+    echo "The VFD specified by the HDF5_DRIVER environment variable"
+    echo "does not support SWMR."
+    echo
+    echo "SWMR acceptance tests skipped"
+    echo
+    exit 0
+fi
+
+# Parse options (none accepted at this time)
+while [ $# -gt 0 ]; do
+    case "$1" in
+    *)  # unknown option
+        echo "$0: Unknown option ($1)"
+        exit 1
+        ;;
+    esac
+done
+
+# HDF5 has several tests that create and delete signal files to communicate
+# between processes, and it seems that even though the names of the files are
+# different, occasionally the wrong file is deleted, interrupting the flow of
+# the test.  Running each of these tests in its own directory should eliminate
+# the problem.
+mkdir vfd_swmr_test
+for FILE in vfd_swmr*; do
+    case "$FILE" in
+        *.o) continue ;;    ## don't copy the .o files
+    esac
+    cp $FILE vfd_swmr_test
+done
+cp vfd_swmr* vfd_swmr_test
+
+# With the --disable-shared option, swmr program files are built in the test
+# directory, otherwise they are in test/.libs with a corresponding wrapper
+# script in the test directory.  The programs or wrapper scripts in test should
+# always be copied, swmr files in .libs should be copied only if they exists.
+if [ -f .libs/swmr ]; then
+    mkdir vfd_swmr_test/.libs
+    for FILE in .libs/vfd_swmr*; do
+        case "$FILE" in
+            *.o) continue ;;    ## don't copy the .o files
+        esac
+        cp $FILE vfd_swmr_test/.libs
+    done
+fi
+
+cd vfd_swmr_test
+
+# Loop over index types
+for index_type in "-i ea" "-i b2" 
+do
+    # Try with and without compression
+    for compress in "" "-c 5"
+    do
+        echo
+        echo "*******************************************************************************"
+        echo "** Loop testing parameters: $index_type $compress"
+        echo "*******************************************************************************"
+        echo
+        echo
+        echo "###############################################################################"
+        echo "## Generator test"
+        echo "###############################################################################"
+        # Launch the Generator without SWMR_WRITE
+        echo launch the vfd_swmr_generator
+        ./vfd_swmr_generator $compress $index_type
+        if test $? -ne 0; then
+            echo generator had error
+            nerrors=`expr $nerrors + 1`
+        fi
+
+        # Launch the Generator with SWMR_WRITE
+        echo launch the vfd_swmr_generator with SWMR_WRITE
+        ./vfd_swmr_generator -s $compress $index_type
+        if test $? -ne 0; then
+            echo generator had error
+            nerrors=`expr $nerrors + 1`
+        fi
+
+        # Check for error and exit if one occured
+        $DPRINT nerrors=$nerrors
+        if test $nerrors -ne 0 ; then
+            echo "SWMR tests failed with $nerrors errors."
+            exit 1
+        fi
+
+        echo
+        echo "###############################################################################"
+        echo "## Writer test - test expanding the dataset"
+        echo "###############################################################################"
+
+        # Launch the Generator
+        echo launch the vfd_swmr_generator
+        ./vfd_swmr_generator -s $compress $index_type
+        if test $? -ne 0; then
+            echo generator had error
+            nerrors=`expr $nerrors + 1`
+        fi
+
+        # Remove any possible writer message file before launching writer
+        rm -f $WRITER_MESSAGE
+        #
+        # Launch the Writer
+        echo launch the vfd_swmr_writer
+        seed="" # Put -r <random seed> command here
+        ./vfd_swmr_writer -o $Nrecords $seed 2>&1 |tee vfd_swmr_writer.out &
+        pid_writer=$!
+        $DPRINT pid_writer=$pid_writer
+
+        # Wait for message from writer process before starting reader(s)
+        WAIT_MESSAGE $WRITER_MESSAGE
+        #
+        # Launch the Readers
+        #declare -a seeds=(<seed1> <seed2> <seed3> ... )
+        echo launch $Nreaders vfd_swmr_readers
+        pid_readers=""
+        n=0
+        while [ $n -lt $Nreaders ]; do
+            #seed="-r ${seeds[$n]}"
+            seed=""
+            ./vfd_swmr_reader $Nsecs_add $seed 2>&1 |tee vfd_swmr_reader.out.$n &
+            pid_readers="$pid_readers $!"
+            n=`expr $n + 1`
+        done
+        $DPRINT pid_readers=$pid_readers
+        $IFDEBUG ps
+
+        # Collect exit code of the readers first because they usually finish
+        # before the writer.
+        for xpid in $pid_readers; do
+            $DPRINT checked reader $xpid
+            wait $xpid
+            if test $? -ne 0; then
+                echo reader had error
+                nerrors=`expr $nerrors + 1`
+            fi
+        done
+
+        # Collect exit code of the writer
+        $DPRINT checked writer $pid_writer
+        wait $pid_writer
+        if test $? -ne 0; then
+            echo writer had error
+            nerrors=`expr $nerrors + 1`
+        fi
+
+        # Check for error and exit if one occured
+        $DPRINT nerrors=$nerrors
+        if test $nerrors -ne 0 ; then
+            echo "VFD SWMR tests failed with $nerrors errors."
+            echo "(Writer and reader output preserved)"
+            exit 1
+        fi
+
+        # Clean up output files
+        ##rm -f vfd_swmr_writer.out
+        ##rm -f vfd_swmr_reader.out.*
+
+    done
+done
+
+###############################################################################
+## Report and exit
+###############################################################################
+cd ..
+$DPRINT nerrors=$nerrors
+if test $nerrors -eq 0 ; then
+    echo "VFD SWMR tests passed."
+    if test -z "$HDF5_NOCLEANUP"; then
+        # delete the test directory
+        rm -rf vfd_swmr_test
+    fi
+    exit 0
+else
+    echo "VFD SWMR tests failed with $nerrors errors."
+    exit 1
+fi
+
diff --git a/test/vfd_swmr_common.c b/test/vfd_swmr_common.c
new file mode 100644
index 0000000..a0d79e3
--- /dev/null
+++ b/test/vfd_swmr_common.c
@@ -0,0 +1,288 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the COPYING file, which can be found at the root of the source code       *
+ * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * If you do not have access to either file, you may request a copy from     *
+ * help@hdfgroup.org.                                                        *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:     swmr_common.c
+ *
+ * Purpose:     Utility functions for the SWMR test code.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/***********/
+/* Headers */
+/***********/
+
+#include "h5test.h"
+#include "swmr_common.h"
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+/* The SWMR data arrays:
+ *
+ * The code uses a 2-D jagged array of datasets.  The first dimension is called
+ * the 'level' and there are five of them.
+ *
+ * #define NLEVELS         5
+ *
+ * The second dimension is the 'count' and there are quite a few datasets per
+ * 'level'.
+ *
+ * unsigned symbol_count[NLEVELS] = {100, 200, 400, 800, 1600};
+ *
+ * These datasets are created when the skeleton is generated and are initially
+ * empty.  Each dataset has no upper bound on size (H5S_UNLIMITED).  They
+ * are of compound type, with two members: an integer ID and an opaque
+ * 'data part'.  The data part is not used by the SWMR testing.
+ *
+ * The SWMR testing will then randomly add and/or remove entries
+ * from these datasets.  The selection of the level is skewed by a mapping
+ * table which preferentially hammers on the lower levels with their smaller
+ * number of datasets.
+ *
+ * static unsigned symbol_mapping[NMAPPING] = {0, 0, 0, 0, 1, 1, 2, 3, 4};
+ *
+ * The information about each dataset (name, hid_t, etc.) is stored in a
+ * separate array.
+ *
+ * symbol_info_t *symbol_info[NLEVELS];
+ */
+
+/* An array of dataset levels, used to select the level for a SWMR operation
+ * Note that this preferentially selects the lower levels with their smaller
+ * number of datasets.
+ */
+static unsigned symbol_mapping[NMAPPING] = {0, 0, 0, 0, 1, 1, 2, 3, 4};
+
+/* The number of datasets at each level */
+unsigned symbol_count[NLEVELS] = {100, 200, 400, 800, 1600};
+
+/* Array of dataset information entries (1 per dataset) */
+symbol_info_t *symbol_info[NLEVELS];
+
+
+/*-------------------------------------------------------------------------
+ * Function:    choose_dataset
+ *
+ * Purpose:     Selects a random dataset in the SWMR file
+ *
+ * Parameters:  N/A
+ *
+ * Return:      Success:    A pointer to information about a dataset.
+ *              Failure:    Can't fail
+ *
+ *-------------------------------------------------------------------------
+ */
+symbol_info_t *
+choose_dataset(void)
+{
+    unsigned level;             /* The level of the dataset */
+    unsigned offset;            /* The "offset" of the dataset at that level */
+
+    /* Determine level of dataset */
+    level = symbol_mapping[HDrandom() % NMAPPING];
+
+    /* Determine the offset of the level */
+    offset = (unsigned)(HDrandom() % (int)symbol_count[level]);
+
+    return &symbol_info[level][offset];
+} /* end choose_dataset() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    create_symbol_datatype
+ *
+ * Purpose:     Create's the HDF5 datatype used for elements in the SWMR
+ *              testing datasets.
+ *
+ * Parameters:  N/A
+ *
+ * Return:      Success:    An HDF5 type ID
+ *              Failure:    -1
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+create_symbol_datatype(void)
+{
+    hid_t sym_type_id;          /* Datatype ID for symbol */
+    hid_t opaq_type_id;         /* Datatype ID for opaque part of record */
+
+    /* Create opaque datatype to represent other information for this record */
+    if((opaq_type_id = H5Tcreate(H5T_OPAQUE, (size_t)DTYPE_SIZE)) < 0)
+        return -1;
+
+    /* Create compound datatype for symbol */
+    if((sym_type_id = H5Tcreate(H5T_COMPOUND, sizeof(symbol_t))) < 0)
+        return -1;
+
+    /* Insert fields in symbol datatype */
+    if(H5Tinsert(sym_type_id, "rec_id", HOFFSET(symbol_t, rec_id), H5T_NATIVE_UINT64) < 0)
+        return -1;
+    if(H5Tinsert(sym_type_id, "info", HOFFSET(symbol_t, info), opaq_type_id) < 0)
+        return -1;
+
+    /* Close opaque datatype */
+    if(H5Tclose(opaq_type_id) < 0)
+        return -1;
+
+    return sym_type_id;
+} /* end create_symbol_datatype() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    generate_name
+ *
+ * Purpose:     Generates a SWMR testing dataset name given a level and
+ *              count.
+ *              The name is in the format <name>-<level> (%u-%04u).
+ *
+ * Parameters:  char *name_buf
+ *              Buffer for the created name.  Must be pre-allocated.
+ *              Since the name is formulaic, this isn't considered an issue.
+ *
+ *              unsigned level
+ *              The dataset's level
+ *
+ *              unsigned count
+ *              The dataset's count
+ *
+ * Return:      Success:    0
+ *                          
+ *              Failure:    Can't fail
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+generate_name(char *name_buf, unsigned level, unsigned count)
+{
+    HDassert(name_buf);
+    
+    sprintf(name_buf, "%u-%04u", level, count);
+
+    return 0;
+} /* end generate_name() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    generate_symbols
+ *
+ * Purpose:     Initializes the global dataset infomration arrays.
+ *
+ * Parameters:  N/A
+ *
+ * Return:      Success:    0
+ *              Failure:    Can't fail
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+generate_symbols(void)
+{
+    unsigned u, v;      /* Local index variables */
+
+    for(u = 0; u < NLEVELS; u++) {
+        symbol_info[u] = (symbol_info_t *)HDmalloc(symbol_count[u] * sizeof(symbol_info_t));
+        for(v = 0; v < symbol_count[u]; v++) {
+            char name_buf[64];
+
+            generate_name(name_buf, u, v);
+            symbol_info[u][v].name = (char *)HDmalloc(HDstrlen(name_buf) + 1);
+            HDstrcpy(symbol_info[u][v].name, name_buf);
+            symbol_info[u][v].dsid = -1;
+            symbol_info[u][v].nrecords = 0;
+        } /* end for */
+    } /* end for */
+
+    return 0;
+} /* end generate_symbols() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    shutdown_symbols
+ *
+ * Purpose:     Cleans up the global dataset information arrays.
+ *
+ * Parameters:  N/A
+ *
+ * Return:      Success:    0
+ *              Failure:    Can't fail
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+shutdown_symbols(void)
+{
+    unsigned u, v;      /* Local index variables */
+
+    /* Clean up the symbols */
+    for(u = 0; u < NLEVELS; u++) {
+        for(v = 0; v < symbol_count[u]; v++)
+            HDfree(symbol_info[u][v].name);
+        HDfree(symbol_info[u]);
+    } /* end for */
+
+    return 0;
+} /* end shutdown_symbols() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    print_metadata_retries_info
+ *
+ * Purpose:     To retrieve and print the collection of metadata retries for the file.
+ *
+ * Parameters:  fid: the currently opened file identifier
+ *
+ * Return:      Success:    0
+ *              Failure:    negative
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+print_metadata_retries_info(hid_t fid)
+{
+    H5F_retry_info_t info;
+    unsigned i;
+
+    /* Retrieve the collection of retries */
+    if(H5Fget_metadata_read_retry_info(fid, &info) < 0)
+        return (-1);
+
+    /* Print information for each non-NULL retries[i] */
+    for(i = 0; i < H5F_NUM_METADATA_READ_RETRY_TYPES; i++) {
+        unsigned power;
+        unsigned j;
+
+        if(NULL == info.retries[i])
+            continue;
+
+        HDfprintf(stderr, "Metadata read retries for item %u:\n", i);
+        power = 1;
+        for(j = 0; j < info.nbins; j++) {
+            if(info.retries[i][j])
+            HDfprintf(stderr, "\t# of retries for %u - %u retries: %u\n", 
+                power, (power * 10) - 1, info.retries[i][j]);
+            power *= 10;
+        } /* end for */
+    } /* end for */
+
+    /* Free memory for each non-NULL retries[i] */
+    for(i = 0; i < H5F_NUM_METADATA_READ_RETRY_TYPES; i++)
+        if(info.retries[i] != NULL)
+            H5free_memory(info.retries[i]);
+
+    return 0;
+} /* print_metadata_retries_info() */
diff --git a/test/vfd_swmr_common.h b/test/vfd_swmr_common.h
new file mode 100644
index 0000000..e77a5ff
--- /dev/null
+++ b/test/vfd_swmr_common.h
@@ -0,0 +1,78 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the COPYING file, which can be found at the root of the source code       *
+ * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * If you do not have access to either file, you may request a copy from     *
+ * help@hdfgroup.org.                                                        *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+#ifndef _SWMR_COMMON_H
+#define _SWMR_COMMON_H
+
+/***********/
+/* Headers */
+/***********/
+
+#include "h5test.h"
+
+/**********/
+/* Macros */
+/**********/
+
+#define NLEVELS         5   /* # of datasets in the SWMR test file */
+
+#define NMAPPING        9   
+
+#define FILENAME        "vfd_swmr_data.h5"  /* SWMR test file name */
+#define DTYPE_SIZE      150             /* Data size in opaque type */
+
+/* The message sent by writer that the file open is done--releasing the file lock */
+#define WRITER_MESSAGE "SWMR_WRITER_MESSAGE"
+
+/************/
+/* Typedefs */
+/************/
+
+/* Information about a symbol/dataset */
+typedef struct {
+    char *name;         /* Dataset name for symbol */
+    hid_t dsid;         /* Dataset ID for symbol */
+    hsize_t nrecords;   /* Number of records for the symbol */
+} symbol_info_t;
+
+/* A symbol's record */
+typedef struct {
+    uint64_t rec_id;    /* ID for this record (unique in symbol) */
+    uint8_t info[DTYPE_SIZE];   /* "Other" information for this record */
+} symbol_t;
+
+/********************/
+/* Global Variables */
+/********************/
+H5TEST_DLLVAR symbol_info_t *symbol_info[NLEVELS];
+H5TEST_DLLVAR unsigned symbol_count[NLEVELS];
+
+/**************/
+/* Prototypes */
+/**************/
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+H5TEST_DLL symbol_info_t * choose_dataset(void);
+H5TEST_DLL hid_t create_symbol_datatype(void);
+H5TEST_DLL int generate_name(char *name_buf, unsigned level, unsigned count);
+H5TEST_DLL int generate_symbols(void);
+H5TEST_DLL int shutdown_symbols(void);
+H5TEST_DLL int print_metadata_retries_info(hid_t fid);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _SWMR_COMMON_H */
diff --git a/test/vfd_swmr_generator.c b/test/vfd_swmr_generator.c
new file mode 100644
index 0000000..3e20d68
--- /dev/null
+++ b/test/vfd_swmr_generator.c
@@ -0,0 +1,415 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the COPYING file, which can be found at the root of the source code       *
+ * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * If you do not have access to either file, you may request a copy from     *
+ * help@hdfgroup.org.                                                        *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:     vfd_swmr_generator.c
+ *
+ * Purpose:     Functions for building and setting up the SWMR test file
+ *              and datasets.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/***********/
+/* Headers */
+/***********/
+
+#include "h5test.h"
+#include "vfd_swmr_common.h"
+
+/*
+ * This file needs to access testing codefrom the H5O package.
+ */
+#define H5O_FRIEND	/*suppress error about including H5Opkg	  */
+#define H5O_TESTING
+#include "H5Opkg.h"     /* Object headers			*/
+
+
+/****************/
+/* Local Macros */
+/****************/
+
+#define CHUNK_SIZE      50      /* Chunk size for created datasets */
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+static int gen_skeleton(const char *filename, hbool_t verbose,
+    hbool_t swmr_write, int comp_level, const char *index_type,
+    unsigned random_seed);
+static void usage(void);
+
+
+/*-------------------------------------------------------------------------
+ * Function:    gen_skeleton
+ *
+ * Purpose:     Creates the HDF5 file and datasets which will be used in
+ *              the SWMR testing.
+ *
+ * Parameters:  const char *filename
+ *              The SWMR test file's name.
+ *
+ *              hbool_t verbose
+ *              Whether verbose console output is desired.
+ *
+ *              hbool_t swmr_write
+ *              Whether to create the file with SWMR writing enabled
+ *
+ *              int comp_level
+ *              The zlib compression level to use. -1 = no compression.
+ *
+ *              const char *index_type
+ *              The chunk index type (b1 | b2 | ea | fa)
+ *
+ *              unsigned random_seed
+ *              The random seed to store in the file.  The sparse tests use
+ *              this value.
+ *
+ * Return:      Success:    0
+ *              Failure:    Can't fail
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+gen_skeleton(const char *filename, hbool_t verbose, hbool_t swmr_write,
+    int comp_level, const char *index_type, unsigned random_seed)
+{
+    hid_t fid;          /* File ID for new HDF5 file */
+    hid_t fcpl;         /* File creation property list */
+    hid_t fapl;         /* File access property list */
+    hid_t dcpl;         /* Dataset creation property list */
+    hid_t tid;          /* Datatype for dataset elements */
+    hid_t sid;          /* Dataspace ID */
+    hid_t aid;          /* Attribute ID */
+    hsize_t dims[2] = {1, 0}; /* Dataset starting dimensions */
+    hsize_t max_dims[2] = {1, H5S_UNLIMITED}; /* Dataset maximum dimensions */
+    hsize_t chunk_dims[2] = {1, CHUNK_SIZE}; /* Chunk dimensions */
+#ifdef FILLVAL_WORKS
+    symbol_t fillval;   /* Dataset fill value */
+#endif /* FILLVAL_WORKS */
+    unsigned u, v;      /* Local index variable */
+    H5F_vfd_swmr_config_t *config = NULL;   /* Configuration for VFD SWMR */
+
+    HDassert(filename);
+    HDassert(index_type);
+
+    /* Create file access property list */
+    if((fapl = h5_fileaccess()) < 0)
+        return -1;
+
+    /* FOR NOW: create the file with the latest format so that the latest chunk indexing will be used */
+    if(H5Pset_libver_bounds(fapl, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST) < 0)
+        return -1;
+
+    /* There are two chunk indexes tested here.
+     * With one unlimited dimension, we get the extensible array index
+     * type, with two unlimited dimensions, we get a v2 B-tree.
+     */
+    if(!HDstrcmp(index_type, "b2"))
+        max_dims[0] = H5S_UNLIMITED;
+
+#ifdef QAK
+    /* Increase the initial size of the metadata cache */
+    {
+        H5AC_cache_config_t mdc_config;
+
+        mdc_config.version = H5AC__CURR_CACHE_CONFIG_VERSION;
+        H5Pget_mdc_config(fapl, &mdc_config);
+        HDfprintf(stderr, "mdc_config.initial_size = %lu\n", (unsigned long)mdc_config.initial_size);
+        HDfprintf(stderr, "mdc_config.epoch_length = %lu\n", (unsigned long)mdc_config.epoch_length);
+        mdc_config.set_initial_size = 1;
+        mdc_config.initial_size = 16 * 1024 * 1024;
+        /* mdc_config.epoch_length = 5000; */
+        H5Pset_mdc_config(fapl, &mdc_config);
+    }
+#endif /* QAK */
+
+#ifdef QAK
+    H5Pset_small_data_block_size(fapl, (hsize_t)(50 * CHUNK_SIZE * DTYPE_SIZE));
+#endif /* QAK */
+
+#ifdef QAK
+    H5Pset_fapl_log(fapl, "append.log", H5FD_LOG_ALL, (size_t)(512 * 1024 * 1024));
+#endif /* QAK */
+
+    /* Create file creation property list */
+    if((fcpl = H5Pcreate(H5P_FILE_CREATE)) < 0)
+        return -1;
+
+#ifdef QAK
+    H5Pset_link_phase_change(fcpl, 0, 0);
+#endif /* QAK */
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(stderr, "Creating file\n");
+
+    /*
+     * Set up to create the file with VFD SWMR configured.
+     */
+
+    if(swmr_write) {
+        /* Set file space strategy to paged aggregation */
+        if(H5Pset_file_space_strategy(fcpl, H5F_FSPACE_STRATEGY_PAGE, FALSE, (hsize_t)1) < 0)
+            return -1;
+
+         /* Enable page buffering */
+        if(H5Pset_page_buffer_size(fapl, 4096, 0, 0) < 0)
+            return -1;
+
+        /* Allocate memory for the configuration structure */
+        if((config = (H5F_vfd_swmr_config_t *)HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
+            return -1;
+
+        config->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
+        config->tick_len = 4;
+        config->max_lag = 6;
+        config->vfd_swmr_writer = TRUE;
+        config->md_pages_reserved = 2;
+        HDstrcpy(config->md_file_path, "my_md_file");
+
+        /* Enable VFD SWMR configuration */
+        if(H5Pset_vfd_swmr_config(fapl, config) < 0)
+            return -1;
+    } 
+
+    /* Create the file with VFD SWMR configured */
+    if((fid = H5Fcreate(filename, H5F_ACC_TRUNC, fcpl, fapl)) < 0)
+        return -1;
+
+    /* Close file creation property list */
+    if(H5Pclose(fcpl) < 0)
+        return -1;
+
+    /* Close file access property list */
+    if(H5Pclose(fapl) < 0)
+        return -1;
+
+    /* Create attribute with (shared) random number seed - for sparse test */
+    if((sid = H5Screate(H5S_SCALAR)) < 0)
+        return -1;
+    if((aid = H5Acreate2(fid, "seed", H5T_NATIVE_UINT, sid, H5P_DEFAULT, H5P_DEFAULT)) < 0)
+        return -1;
+    if(H5Awrite(aid, H5T_NATIVE_UINT, &random_seed) < 0)
+        return -1;
+    if(H5Sclose(sid) < 0)
+        return -1;
+
+    /* Create datatype for creating datasets */
+    if((tid = create_symbol_datatype()) < 0)
+        return -1;
+
+    /* Create dataspace for creating datasets */
+    if((sid = H5Screate_simple(2, dims, max_dims)) < 0)
+        return -1;
+
+    /* Create dataset creation property list */
+    if((dcpl = H5Pcreate(H5P_DATASET_CREATE)) < 0)
+        return -1;
+    if(H5Pset_chunk(dcpl, 2, chunk_dims) < 0)
+        return -1;
+    if(comp_level >= 0) {
+        if(H5Pset_deflate(dcpl, (unsigned)comp_level) < 0)
+            return -1;
+    } /* end if */
+#ifdef FILLVAL_WORKS
+    /* Currently fill values do not work because they can bump the dataspace
+     * message to the second object header chunk.  We should enable the fillval
+     * here when this is fixed.  -NAF 8/11/11 */
+    HDmemset(&fillval, 0, sizeof(fillval));
+    fillval.rec_id = (uint64_t)ULLONG_MAX;
+    if(H5Pset_fill_value(dcpl, tid, &fillval) < 0)
+        return -1;
+#endif /* FILLVAL_WORKS */
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(stderr, "Creating datasets\n");
+
+    /* Create the datasets */
+    for(u = 0; u < NLEVELS; u++)
+        for(v = 0; v < symbol_count[u]; v++) {
+            hid_t dsid;         /* Dataset ID */
+            char name_buf[64];
+            hbool_t move_dataspace_message = FALSE;     /* Whether to move the dataspace message out of object header chunk #0 */
+
+            generate_name(name_buf, u, v);
+            if((dsid = H5Dcreate2(fid, name_buf, tid, sid, H5P_DEFAULT, dcpl, H5P_DEFAULT)) < 0)
+                return -1;
+
+            /* Determine if the dataspace message for this dataset should be
+             * moved out of chunk #0 of the object header
+             * (Set to TRUE for every fourth dataset)
+             */
+            move_dataspace_message = !(HDrandom() % 4);
+            if(move_dataspace_message) {
+                unsigned chunk_num;        /* Object header chunk # for dataspace message */
+
+                /* Move the dataspace message to a new object header chunk */
+                if(H5O__msg_move_to_new_chunk_test(dsid, H5O_SDSPACE_ID) < 0)
+                    return -1;
+
+                /* Retrieve the chunk # for the dataspace message */
+                chunk_num = UINT_MAX;
+                if(H5O__msg_get_chunkno_test(dsid, H5O_SDSPACE_ID, &chunk_num) < 0)
+                    return -1;
+                /* Should not be in chunk #0 for now */
+                if(0 == chunk_num)
+                    return -1;
+            } /* end if */
+
+            if(H5Dclose(dsid) < 0)
+                return -1;
+        } /* end for */
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(stderr, "Closing objects\n");
+
+    /* Close everythign */
+    if(H5Pclose(dcpl) < 0)
+        return -1;
+    if(H5Sclose(sid) < 0)
+        return -1;
+    if(H5Tclose(tid) < 0)
+        return -1;
+    if(H5Fclose(fid) < 0)
+        return -1;
+
+    /* Free the config structure */
+    if(config)
+        HDfree(config);
+    return 0;
+} /* end gen_skeleton() */
+
+static void
+usage(void)
+{
+    printf("\n");
+    printf("Usage error!\n");
+    printf("\n");
+    printf("Usage: swmr_generator [-q] [-s] [-c <deflate compression level>]\n");
+    printf("    [-i <index type>] [-r <random seed>]\n");
+    printf("\n");
+    printf("NOTE: The random seed option is only used by the sparse test.  Other\n");
+    printf("      tests specify the random seed as a reader/writer option.\n");
+    printf("\n");
+    printf("<deflate compression level> should be -1 (for no compression) or 0-9\n");
+    printf("\n");
+    printf("<index type> should be b2 or ea\n");
+    printf("\n");
+    printf("Defaults to verbose (no '-q' given), no SWMR_WRITE mode (no '-s' given) no\n");
+    printf("compression ('-c -1'), v1 b-tree indexing (-i b1), and will generate a random\n");
+    printf("seed (no -r given).\n");
+    printf("\n");
+    HDexit(1);
+} /* end usage() */
+
+int main(int argc, const char *argv[])
+{
+    int comp_level = -1;            /* Compression level (-1 is no compression) */
+    hbool_t verbose = TRUE;         /* Whether to emit some informational messages */
+    hbool_t swmr_write = FALSE;     /* Whether to create file with SWMR_WRITE access */
+    const char *index_type = "b1";  /* Chunk index type */
+    hbool_t use_seed = FALSE;       /* Set to TRUE if a seed was set on the command line */
+    unsigned random_seed = 0;       /* Random # seed */
+    unsigned u;                     /* Local index variables */
+    int temp;
+
+    /* Parse command line options */
+    if(argc > 1) {
+        u = 1;
+        while(u < (unsigned)argc) {
+            if(argv[u][0] == '-') {
+                switch(argv[u][1]) {
+                    /* Compress dataset chunks */
+                    case 'c':
+                        comp_level = HDatoi(argv[u + 1]);
+                        if(comp_level < -1 || comp_level > 9)
+                            usage();
+                        u += 2;
+                        break;
+
+                    /* Chunk index type */
+                    case 'i':
+                        index_type = argv[u + 1];
+                        if(HDstrcmp(index_type, "ea")
+                                && HDstrcmp(index_type, "b2"))
+                            usage();
+                        u += 2;
+                        break;
+
+                    /* Random # seed */
+                    case 'r':
+                        use_seed = TRUE;
+                        temp = HDatoi(argv[u + 1]);
+                        if(temp < 0)
+                            usage();
+                        else
+                            random_seed = (unsigned)temp;
+                        u += 2;
+                        break;
+
+                    /* Be quiet */
+                    case 'q':
+                        verbose = FALSE;
+                        u++;
+                        break;
+
+                    /* Run with SWMR_WRITE */
+                    case 's':
+                        swmr_write = TRUE;
+                        u++;
+                        break;
+
+                    default:
+                        usage();
+                        break;
+                } /* end switch */
+            } /* end if */
+        } /* end while */
+    } /* end if */
+
+    /* Emit informational message */
+    if(verbose) {
+        HDfprintf(stderr, "Parameters:\n");
+        HDfprintf(stderr, "\tswmr writes %s\n", swmr_write ? "on" : "off");
+        HDfprintf(stderr, "\tcompression level = %d\n", comp_level);
+        HDfprintf(stderr, "\tindex type = %s\n", index_type);
+    } /* end if */
+    
+    /* Set the random seed */
+    if(!use_seed) {
+        struct timeval t;
+
+        HDgettimeofday(&t, NULL);
+        random_seed = (unsigned)(t.tv_usec);
+    } /* end if */
+    HDsrandom(random_seed);
+    /* ALWAYS emit the random seed for possible debugging */
+    HDfprintf(stderr, "Using generator random seed (used in sparse test only): %u\n", random_seed);
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(stderr, "Generating skeleton file: %s\n", FILENAME);
+
+    /* Generate file skeleton */
+    if(gen_skeleton(FILENAME, verbose, swmr_write, comp_level, index_type, random_seed) < 0) {
+        HDfprintf(stderr, "Error generating skeleton file!\n");
+        HDexit(1);
+    } /* end if */
+
+    return 0;
+}
diff --git a/test/vfd_swmr_reader.c b/test/vfd_swmr_reader.c
new file mode 100644
index 0000000..d074771
--- /dev/null
+++ b/test/vfd_swmr_reader.c
@@ -0,0 +1,575 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the COPYING file, which can be found at the root of the source code       *
+ * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * If you do not have access to either file, you may request a copy from     *
+ * help@hdfgroup.org.                                                        *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:     vfd_swmr_reader.c
+ *
+ * Purpose:     Reads data from a randomly selected subset of the datasets
+ *              in the SWMR test file.
+ *
+ *              This program is intended to run concurrently with the
+ *              swmr_writer program.
+ *
+ *              This is copied from swmr_reader.c and modified for testing 
+ *              with VFD SWMR.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/***********/
+/* Headers */
+/***********/
+
+#include "h5test.h"
+#include "vfd_swmr_common.h"
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+static int check_dataset(hid_t fid, hbool_t verbose, FILE *verbose_file,
+    const char *sym_name, symbol_t *record, hid_t rec_sid);
+static int read_records(const char *filename, hbool_t verbose, FILE *verbose_file,
+    unsigned random_seed, unsigned long nseconds, unsigned poll_time,
+    unsigned ncommon, unsigned nrandom);
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+static hid_t symbol_tid = -1;   /* The type ID for the SWMR datasets */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    check_dataset
+ *
+ * Purpose:     For a given dataset, checks to make sure that the stated
+ *              and actual sizes are the same.  If they are not, then
+ *              we have an inconsistent dataset due to a SWMR error.
+ *
+ * Parameters:  hid_t fid
+ *              The SWMR test file's ID.
+ *
+ *              hbool_t verbose
+ *              Whether verbose console output is desired.
+ *
+ *              FILE *verbose_file
+ *              File handle for verbose output
+ *
+ *              const char *sym_name
+ *              The name of the dataset from which to read.
+ *
+ *              symbol_t *record
+ *              Memory for the record.  Must be pre-allocated.
+ *
+ *              hid_t rec_sid
+ *              The memory dataspace for access.  It's always the same so
+ *              there is no need to re-create it every time this function
+ *              is called.
+ *
+ * Return:      Success:    0
+ *              Failure:    -1
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+check_dataset(hid_t fid, hbool_t verbose, FILE *verbose_file,
+    const char *sym_name, symbol_t *record, hid_t rec_sid)
+{
+    hid_t dsid;                 /* Dataset ID */
+    hid_t file_sid;             /* Dataset's space ID */
+    hssize_t snpoints;          /* Number of elements in dataset */
+    hsize_t start[2] = {0, 0}, count[2] = {1, 1};   /* Hyperslab selection values */
+
+    HDassert(fid >= 0);
+    HDassert(sym_name);
+    HDassert(record);
+    HDassert(rec_sid >= 0);
+
+    /* Open dataset for symbol */
+    if((dsid = H5Dopen2(fid, sym_name, H5P_DEFAULT)) < 0)
+        return -1;
+
+    /* Get the dataset's dataspace */
+    if((file_sid = H5Dget_space(dsid)) < 0)
+        return -1;
+
+    /* Get the number of elements (= records, for 1-D datasets) */
+    if((snpoints = H5Sget_simple_extent_npoints(file_sid)) < 0)
+        return -1;
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Symbol = '%s', # of records = %lld\n", sym_name, (long long)snpoints);
+
+    /* Check if there are records for symbol */
+    if(snpoints > 0) {
+        /* Choose the last record in the dataset */
+        start[1] = (hsize_t)(snpoints - 1);
+        if(H5Sselect_hyperslab(file_sid, H5S_SELECT_SET, start, NULL, count, NULL) < 0)
+            return -1;
+
+        /* Read record from dataset */
+        record->rec_id = (uint64_t)ULLONG_MAX;
+        if(H5Dread(dsid, symbol_tid, rec_sid, file_sid, H5P_DEFAULT, record) < 0)
+            return -1;
+
+        /* Verify record value */
+        if(record->rec_id != start[1]) {
+            struct timeval tv;
+
+            HDgettimeofday(&tv, NULL);
+
+            if(verbose) {
+                HDfprintf(verbose_file, "*** ERROR ***\n");
+                HDfprintf(verbose_file, "Incorrect record value!\n");
+                HDfprintf(verbose_file, "Time = %llu.%llu, Symbol = '%s', # of records = %lld, record->rec_id = %llu\n", (unsigned long long)tv.tv_sec, (unsigned long long)tv.tv_usec, sym_name, (long long)snpoints, (unsigned long long)record->rec_id);
+            } /* end if */
+            return -1;
+        } /* end if */
+    } /* end if */
+
+    /* Close the dataset's dataspace */
+    if(H5Sclose(file_sid) < 0)
+        return -1;
+
+    /* Close dataset for symbol */
+    if(H5Dclose(dsid) < 0)
+        return -1;
+
+    return 0;
+} /* end check_dataset() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    read_records
+ *
+ * Purpose:     For a given dataset, checks to make sure that the stated
+ *              and actual sizes are the same.  If they are not, then
+ *              we have an inconsistent dataset due to a SWMR error.
+ *
+ *              The "common" datasets are a random selection from among
+ *              the level 0 datasets.  The "random" datasets are a random
+ *              selection from among all the file's datasets.  This scheme
+ *              ensures that the level 0 datasets are interrogated vigorously.
+ *
+ * Parameters:  const char *filename
+ *              The SWMR test file's name.
+ *
+ *              hbool_t verbose
+ *              Whether verbose console output is desired.
+ *
+ *              FILE *verbose_file
+ *              File handle for verbose output
+ *
+ *              unsigned random_seed
+ *              Random seed for the file (used for verbose logging)
+ *
+ *              unsigned long nseconds
+ *              The amount of time to read records (ns).
+ *
+ *              unsigned poll_time
+ *              The amount of time to sleep (s).
+ *
+ *              unsigned ncommon
+ *              The number of common/non-random datasets that will be opened.
+ *
+ *              unsigned nrandom
+ *              The number of random datasets that will be opened.
+ *
+ * Return:      Success:    0
+ *              Failure:    -1
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+read_records(const char *filename, hbool_t verbose, FILE *verbose_file,
+    unsigned random_seed, unsigned long nseconds, unsigned poll_time,
+    unsigned ncommon, unsigned nrandom)
+{
+    time_t start_time;          /* Starting time */
+    time_t curr_time;           /* Current time */
+    symbol_info_t **sym_com = NULL;     /* Pointers to array of common dataset IDs */
+    symbol_info_t **sym_rand = NULL;    /* Pointers to array of random dataset IDs */
+    hid_t mem_sid;              /* Memory dataspace ID */
+    hid_t fid;                  /* SWMR test file ID */
+    hid_t fapl;                 /* file access property list */
+    symbol_t record;            /* The record to read from the dataset */
+    unsigned v;                 /* Local index variable */
+    hbool_t use_log_vfd = FALSE;    /* Use the log VFD (set this manually) */
+H5F_vfd_swmr_config_t *config = NULL;   /* Configuration for VFD SWMR */
+
+    HDassert(filename);
+    HDassert(nseconds != 0);
+    HDassert(poll_time != 0);
+
+    /* Reset the record */
+    /* (record's 'info' field might need to change for each record read, also) */
+    HDmemset(&record, 0, sizeof(record));
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Choosing datasets\n");
+
+    /* Allocate space for 'common' datasets, if any */
+    if(ncommon > 0) {
+        /* Allocate array to hold pointers to symbols for common datasets */
+        if(NULL == (sym_com = (symbol_info_t **)HDmalloc(sizeof(symbol_info_t *) * ncommon)))
+            return -1;
+
+        /* Open the common datasets */
+        for(v = 0; v < ncommon; v++) {
+            unsigned offset;                /* Offset of symbol to use */
+
+            /* Determine the offset of the symbol, within level 0 symbols */
+            /* (level 0 symbols are the most common symbols) */
+            offset = (unsigned)((unsigned)HDrandom() % symbol_count[0]);
+            sym_com[v] = &symbol_info[0][offset];
+
+            /* Emit informational message */
+            if(verbose)
+                HDfprintf(verbose_file, "Common symbol #%u = '%s'\n", v, symbol_info[0][offset].name);
+        } /* end for */
+    } /* end if */
+
+    /* Allocate space for 'random' datasets, if any */
+    if(nrandom > 0) {
+        /* Allocate array to hold pointers to symbols for random datasets */
+        if(NULL == (sym_rand = (symbol_info_t **)HDmalloc(sizeof(symbol_info_t *) * nrandom)))
+            return -1;
+
+        /* Determine the random datasets */
+        for(v = 0; v < nrandom; v++) {
+            symbol_info_t *sym;         /* Symbol to use */
+
+            /* Determine the symbol, within all symbols */
+            if(NULL == (sym = choose_dataset()))
+                return -1;
+            sym_rand[v] = sym;
+
+            /* Emit informational message */
+            if(verbose)
+                HDfprintf(verbose_file, "Random symbol #%u = '%s'\n", v, sym->name);
+        } /* end for */
+    } /* end if */
+
+    /* Create a dataspace for the record to read */
+    if((mem_sid = H5Screate(H5S_SCALAR)) < 0)
+        return -1;
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Reading records\n");
+
+    /* Get the starting time */
+    start_time = HDtime(NULL);
+    curr_time = start_time;
+
+    /* Create file access property list */
+    if((fapl = h5_fileaccess()) < 0)
+        return -1;
+
+    /* Log I/O when verbose output it enbabled */
+    if(use_log_vfd) {
+        char verbose_name[1024];
+
+        HDsnprintf(verbose_name, sizeof(verbose_name), "swmr_reader.log.%u", random_seed);
+
+        H5Pset_fapl_log(fapl, verbose_name, H5FD_LOG_ALL, (size_t)(512 * 1024 * 1024));
+    } /* end if */
+
+    /* Loop over reading records until [at least] the correct # of seconds have passed */
+    while(curr_time < (time_t)(start_time + (time_t)nseconds)) {
+
+        /* Emit informational message */
+        if(verbose)
+            HDfprintf(verbose_file, "Opening file: %s\n", filename);
+
+        /*
+         * Set up to open the file with VFD SWMR configured.
+         */
+         /* Enable page buffering */
+        if(H5Pset_page_buffer_size(fapl, 4096, 0, 0) < 0)
+            return -1;
+
+         /* Allocate memory for the configuration structure */
+        if((config = (H5F_vfd_swmr_config_t *)HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
+            return -1;
+
+        config->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
+        config->tick_len = 4;
+        config->max_lag = 6;
+        config->vfd_swmr_writer = FALSE;
+        config->md_pages_reserved = 2;
+        HDstrcpy(config->md_file_path, "./my_md_file");
+
+        /* Enable VFD SWMR configuration */
+        if(H5Pset_vfd_swmr_config(fapl, config) < 0)
+            return -1;
+
+        /* Open the file with VFD SWMR configured */
+        if((fid = H5Fopen(filename, H5F_ACC_RDONLY, fapl)) < 0)
+            return -1;
+
+        /* Check 'common' datasets, if any */
+        if(ncommon > 0) {
+            /* Emit informational message */
+            if(verbose)
+                HDfprintf(verbose_file, "Checking common symbols\n");
+
+            /* Iterate over common datasets */
+            for(v = 0; v < ncommon; v++) {
+                /* Check common dataset */
+                if(check_dataset(fid, verbose, verbose_file, sym_com[v]->name, &record, mem_sid) < 0)
+                    return -1;
+                HDmemset(&record, 0, sizeof(record));
+            } /* end for */
+        } /* end if */
+
+        /* Check 'random' datasets, if any */
+        if(nrandom > 0) {
+            /* Emit informational message */
+            if(verbose)
+                HDfprintf(verbose_file, "Checking random symbols\n");
+
+            /* Iterate over random datasets */
+            for(v = 0; v < nrandom; v++) {
+                /* Check random dataset */
+                if(check_dataset(fid, verbose, verbose_file, sym_rand[v]->name, &record, mem_sid) < 0)
+                    return -1;
+                HDmemset(&record, 0, sizeof(record));
+            } /* end for */
+        } /* end if */
+
+        /* Emit informational message */
+        if(verbose)
+            HDfprintf(verbose_file, "Closing file\n");
+            
+        /* Close the file */
+        if(H5Fclose(fid) < 0)
+            return -1;
+
+        /* Sleep for the appropriate # of seconds */
+        HDsleep(poll_time);
+
+        /* Retrieve the current time */
+        curr_time = HDtime(NULL);
+    } /* end while */
+
+    /* Close the memory dataspace */
+    if(H5Sclose(mem_sid) < 0)
+        return -1;
+
+    /* Close the fapl */
+    if(H5Pclose(fapl) < 0)
+        return -1;
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Closing datasets\n");
+
+    /* Close 'random' datasets, if any */
+    if(nrandom > 0) {
+        /* Release array holding dataset ID's for random datasets */
+        HDfree(sym_rand);
+    } /* end if */
+
+    /* Close 'common' datasets, if any */
+    if(ncommon > 0) {
+        /* Release array holding dataset ID's for common datasets */
+        HDfree(sym_com);
+    } /* end if */
+
+    /* Free the config structure */
+    if(config)
+        HDfree(config);
+    return 0;
+} /* end read_records() */
+
+static void
+usage(void)
+{
+    printf("\n");
+    printf("Usage error!\n");
+    printf("\n");
+    printf("Usage: swmr_reader [-q] [-s <# of seconds to sleep between polling>]\n");
+    printf("    [-h <# of common symbols to poll>] [-l <# of random symbols to poll>]\n");
+    printf("    [-r <random seed>] <# of seconds to test>\n");
+    printf("\n");
+    printf("<# of seconds to test> must be specified.\n");
+    printf("\n");
+    printf("Defaults to verbose (no '-q' given), 1 second between polling ('-s 1'),\n");
+    printf("5 common symbols to poll ('-h 5'), 10 random symbols to poll ('-l 10'),\n");
+    printf("and will generate a random seed (no -r given).\n");
+    printf("\n");
+    HDexit(1);
+}
+
+int main(int argc, const char *argv[])
+{
+    long nseconds = 0;      /* # of seconds to test */
+    int poll_time = 1;      /* # of seconds between polling */
+    int ncommon = 5;        /* # of common symbols to poll */
+    int nrandom = 10;       /* # of random symbols to poll */
+    hbool_t verbose = TRUE; /* Whether to emit some informational messages */
+    FILE *verbose_file = NULL;  /* File handle for verbose output */
+    hbool_t use_seed = FALSE; /* Set to 1 if a seed was set on the command line */
+    unsigned random_seed = 0;   /* Random # seed */
+    unsigned u;             /* Local index variables */
+    int temp;
+
+    /* Parse command line options */
+    if(argc < 2)
+        usage();
+    if(argc > 1) {
+        u = 1;
+        while(u < (unsigned)argc) {
+            if(argv[u][0] == '-') {
+                switch(argv[u][1]) {
+                    /* # of common symbols to poll */
+                    case 'h':
+                        ncommon = HDatoi(argv[u + 1]);
+                        if(ncommon < 0)
+                            usage();
+                        u += 2;
+                        break;
+
+                    /* # of random symbols to poll */
+                    case 'l':
+                        nrandom = HDatoi(argv[u + 1]);
+                        if(nrandom < 0)
+                            usage();
+                        u += 2;
+                        break;
+
+                    /* Be quiet */
+                    case 'q':
+                        verbose = FALSE;
+                        u++;
+                        break;
+
+                    /* Random # seed */
+                    case 'r':
+                        use_seed = TRUE;
+                        temp = HDatoi(argv[u + 1]);
+                        if(temp < 0)
+                            usage();
+                        else
+                            random_seed = (unsigned)temp;
+                        u += 2;
+                        break;
+
+                    /* # of seconds between polling */
+                    case 's':
+                        poll_time = HDatoi(argv[u + 1]);
+                        if(poll_time < 0)
+                            usage();
+                        u += 2;
+                        break;
+
+                    default:
+                        usage();
+                        break;
+                } /* end switch */
+            } /* end if */
+            else {
+                /* Get the number of records to append */
+                nseconds = HDatol(argv[u]);
+                if(nseconds <= 0)
+                    usage();
+
+                u++;
+            } /* end else */
+        } /* end while */
+    } /* end if */
+    if(nseconds <= 0)
+        usage();
+    if(poll_time >= nseconds)
+        usage();
+
+    /* Set the random seed */
+    if(!use_seed) {
+        struct timeval t;
+
+        HDgettimeofday(&t, NULL);
+        random_seed = (unsigned)(t.tv_usec);
+    } /* end if */
+    HDsrandom(random_seed);
+
+    /* Open output file */
+    if(verbose) {
+        char verbose_name[1024];
+
+        HDsnprintf(verbose_name, sizeof(verbose_name), "swmr_reader.out.%u", random_seed);
+        if(NULL == (verbose_file = HDfopen(verbose_name, "w"))) {
+            HDfprintf(stderr, "Can't open verbose output file!\n");
+            HDexit(1);
+        }
+    } /* end if */
+
+    /* Emit informational message */
+    if(verbose) {
+        HDfprintf(verbose_file, "Parameters:\n");
+        HDfprintf(verbose_file, "\t# of seconds between polling = %d\n", poll_time);
+        HDfprintf(verbose_file, "\t# of common symbols to poll = %d\n", ncommon);
+        HDfprintf(verbose_file, "\t# of random symbols to poll = %d\n", nrandom);
+        HDfprintf(verbose_file, "\t# of seconds to test = %ld\n", nseconds);
+    } /* end if */
+
+    /* ALWAYS emit the random seed for possible debugging */
+    HDfprintf(stdout, "Using reader random seed: %u\n", random_seed);
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Generating symbol names\n");
+
+    /* Generate dataset names */
+    if(generate_symbols() < 0) {
+        HDfprintf(stderr, "Error generating symbol names!\n");
+        HDexit(1);
+    } /* end if */
+
+    /* Create datatype for creating datasets */
+    if((symbol_tid = create_symbol_datatype()) < 0)
+        return -1;
+
+    /* Reading records from datasets */
+    if(read_records(FILENAME, verbose, verbose_file, random_seed, (unsigned long)nseconds, (unsigned)poll_time, (unsigned)ncommon, (unsigned)nrandom) < 0) {
+        HDfprintf(stderr, "Error reading records from datasets (random_seed = %u)!\n", random_seed);
+        HDexit(1);
+    } /* end if */
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Releasing symbols\n");
+
+    /* Clean up the symbols */
+    if(shutdown_symbols() < 0) {
+        HDfprintf(stderr, "Error releasing symbols!\n");
+        HDexit(1);
+    } /* end if */
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Closing objects\n");
+
+    /* Close objects created */
+    if(H5Tclose(symbol_tid) < 0) {
+        HDfprintf(stderr, "Error closing symbol datatype!\n");
+        HDexit(1);
+    } /* end if */
+
+    return 0;
+}
+
diff --git a/test/vfd_swmr_writer.c b/test/vfd_swmr_writer.c
new file mode 100644
index 0000000..bf4acb7
--- /dev/null
+++ b/test/vfd_swmr_writer.c
@@ -0,0 +1,473 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the COPYING file, which can be found at the root of the source code       *
+ * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * If you do not have access to either file, you may request a copy from     *
+ * help@hdfgroup.org.                                                        *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:     swmr_writer.c
+ *
+ * Purpose:     Writes data to a randomly selected subset of the datasets
+ *              in the SWMR test file.
+ *
+ *              This program is intended to run concurrently with the
+ *              swmr_reader program.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/***********/
+/* Headers */
+/***********/
+
+#include "h5test.h"
+#include "vfd_swmr_common.h"
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+static hid_t open_skeleton(const char *filename, hbool_t verbose, FILE *verbose_file,
+    unsigned random_seed, hbool_t old);
+static int add_records(hid_t fid, hbool_t verbose, FILE *verbose_file,
+    unsigned long nrecords, unsigned long flush_count);
+static void usage(void);
+
+
+/*-------------------------------------------------------------------------
+ * Function:    open_skeleton
+ *
+ * Purpose:     Opens the SWMR HDF5 file and datasets.
+ *
+ * Parameters:  const char *filename
+ *              The filename of the SWMR HDF5 file to open
+ *
+ *              hbool_t verbose
+ *              Whether or not to emit verbose console messages
+ *
+ *              FILE *verbose_file
+ *              File handle for verbose output
+ *
+ *              unsigned random_seed
+ *              Random seed for the file (used for verbose logging)
+ *
+ *              hbool_t old
+ *              Whether to write in "old" file format
+ *
+ * Return:      Success:    The file ID of the opened SWMR file
+ *                          The dataset IDs are stored in a global array
+ *
+ *              Failure:    -1
+ *
+ *-------------------------------------------------------------------------
+ */
+static hid_t
+open_skeleton(const char *filename, hbool_t verbose, FILE *verbose_file,
+    unsigned random_seed, hbool_t old)
+{
+    hid_t fid;          /* File ID for new HDF5 file */
+    hid_t fapl;         /* File access property list */
+    unsigned u, v;      /* Local index variable */
+    hbool_t use_log_vfd = FALSE;    /* Use the log VFD (set this manually) */
+H5F_vfd_swmr_config_t *config = NULL;   /* Configuration for VFD SWMR */
+
+    HDassert(filename);
+
+    /* Create file access property list */
+    if((fapl = h5_fileaccess()) < 0)
+        return -1;
+
+    /* FOR NOW: set to use latest format, the "old"parameter is not used */
+    if(H5Pset_libver_bounds(fapl, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST) < 0)
+        return -1;
+
+#ifdef QAK
+    /* Increase the initial size of the metadata cache */
+    {
+        H5AC_cache_config_t mdc_config;
+
+        mdc_config.version = H5AC__CURR_CACHE_CONFIG_VERSION;
+        H5Pget_mdc_config(fapl, &mdc_config);
+        HDfprintf(stderr, "mdc_config.initial_size = %lu\n", (unsigned long)mdc_config.initial_size);
+        HDfprintf(stderr, "mdc_config.epoch_length = %lu\n", (unsigned long)mdc_config.epoch_length);
+        mdc_config.set_initial_size = 1;
+        mdc_config.initial_size = 16 * 1024 * 1024;
+        /* mdc_config.epoch_length = 5000; */
+        H5Pset_mdc_config(fapl, &mdc_config);
+    }
+#endif /* QAK */
+
+    if(use_log_vfd) {
+        char verbose_name[1024];
+
+        HDsnprintf(verbose_name, sizeof(verbose_name), "swmr_writer.log.%u", random_seed);
+
+        H5Pset_fapl_log(fapl, verbose_name, H5FD_LOG_ALL, (size_t)(512 * 1024 * 1024));
+    } /* end if */
+
+    /*
+     * Set up to open the file with VFD SWMR configured.
+     */
+
+    /* Enable page buffering */
+    if(H5Pset_page_buffer_size(fapl, 4096, 0, 0) < 0)
+        return -1;
+
+     /* Allocate memory for the configuration structure */
+     if((config = (H5F_vfd_swmr_config_t *)HDmalloc(sizeof(H5F_vfd_swmr_config_t))) == NULL)
+        return -1;
+
+    config->version = H5F__CURR_VFD_SWMR_CONFIG_VERSION;
+    config->tick_len = 4;
+    config->max_lag = 6;
+    config->vfd_swmr_writer = TRUE;
+    config->md_pages_reserved = 2;
+    HDstrcpy(config->md_file_path, "./my_md_file");
+
+    /* Enable VFD SWMR configuration */
+    if(H5Pset_vfd_swmr_config(fapl, config) < 0)
+        return -1;
+
+    /* Open the file with VFD SWMR configured */
+    if((fid = H5Fopen(filename, H5F_ACC_RDWR, fapl)) < 0)
+        return -1;
+
+    /* Close file access property list */
+    if(H5Pclose(fapl) < 0)
+        return -1;
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Opening datasets\n");
+
+    /* Open the datasets */
+    for(u = 0; u < NLEVELS; u++)
+        for(v = 0; v < symbol_count[u]; v++) {
+            if((symbol_info[u][v].dsid = H5Dopen2(fid, symbol_info[u][v].name, H5P_DEFAULT)) < 0)
+                return -1;
+            symbol_info[u][v].nrecords = 0;
+        } /* end for */
+
+    if(config)
+        HDfree(config);
+    return fid;
+} /* open_skeleton() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    add_records
+ *
+ * Purpose:     Writes a specified number of records to random datasets in
+ *              the SWMR test file.
+ *
+ * Parameters:  hid_t fid
+ *              The file ID of the SWMR HDF5 file
+ *
+ *              hbool_t verbose
+ *              Whether or not to emit verbose console messages
+ *
+ *              FILE *verbose_file
+ *              File handle for verbose output
+ *
+ *              unsigned long nrecords
+ *              # of records to write to the datasets
+ *
+ *              unsigned long flush_count
+ *              # of records to write before flushing the file to disk
+ *
+ * Return:      Success:    0
+ *              Failure:    -1
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+add_records(hid_t fid, hbool_t verbose, FILE *verbose_file,
+    unsigned long nrecords, unsigned long flush_count)
+{
+    hid_t tid;                              /* Datatype ID for records */
+    hid_t mem_sid;                          /* Memory dataspace ID */
+    hsize_t start[2] = {0, 0}, count[2] = {1, 1}; /* Hyperslab selection values */
+    hsize_t dim[2] = {1, 0};                /* Dataspace dimensions */
+    symbol_t record;                        /* The record to add to the dataset */
+    unsigned long rec_to_flush;             /* # of records left to write before flush */
+    unsigned long u, v;                     /* Local index variables */
+
+    HDassert(fid >= 0);
+
+    /* Reset the record */
+    /* (record's 'info' field might need to change for each record written, also) */
+    HDmemset(&record, 0, sizeof(record));
+
+    /* Create a dataspace for the record to add */
+    if((mem_sid = H5Screate(H5S_SCALAR)) < 0)
+        return -1;
+
+    /* Create datatype for appending records */
+    if((tid = create_symbol_datatype()) < 0)
+        return -1;
+
+    /* Add records to random datasets, according to frequency distribution */
+    rec_to_flush = flush_count;
+    for(u = 0; u < nrecords; u++) {
+        symbol_info_t *symbol;  /* Symbol to write record to */
+        hid_t file_sid;         /* Dataset's space ID */
+
+        /* Get a random dataset, according to the symbol distribution */
+        symbol = choose_dataset();
+
+        /* Set the record's ID (equal to its position) */
+        record.rec_id = symbol->nrecords;
+
+        /* Get the coordinate to write */
+        start[1] = symbol->nrecords;
+
+        /* Cork the metadata cache, to prevent the object header from being
+         * flushed before the data has been written */
+        if(H5Odisable_mdc_flushes(symbol->dsid) < 0)
+            return -1;
+
+        /* Extend the dataset's dataspace to hold the new record */
+        symbol->nrecords++;
+        dim[1] = symbol->nrecords;
+        if(H5Dset_extent(symbol->dsid, dim) < 0)
+            return -1;
+
+        /* Get the dataset's dataspace */
+        if((file_sid = H5Dget_space(symbol->dsid)) < 0)
+            return -1;
+
+        /* Choose the last record in the dataset */
+        if(H5Sselect_hyperslab(file_sid, H5S_SELECT_SET, start, NULL, count, NULL) < 0)
+            return -1;
+
+        /* Write record to the dataset */
+        if(H5Dwrite(symbol->dsid, tid, mem_sid, file_sid, H5P_DEFAULT, &record) < 0)
+            return -1;
+
+        /* Uncork the metadata cache */
+        if(H5Oenable_mdc_flushes(symbol->dsid) < 0)
+            return -1;
+
+        /* Close the dataset's dataspace */
+        if(H5Sclose(file_sid) < 0)
+            return -1;
+
+        /* Check for flushing file */
+        if(flush_count > 0) {
+            /* Decrement count of records to write before flushing */
+            rec_to_flush--;
+
+            /* Check for counter being reached */
+            if(0 == rec_to_flush) {
+                /* Flush contents of file */
+                if(H5Fflush(fid, H5F_SCOPE_GLOBAL) < 0)
+                    return -1;
+
+                /* Reset flush counter */
+                rec_to_flush = flush_count;
+            } /* end if */
+        } /* end if */
+    } /* end for */
+
+    /* Close the memory dataspace */
+    if(H5Sclose(mem_sid) < 0)
+        return -1;
+
+    /* Close the datatype */
+    if(H5Tclose(tid) < 0)
+        return -1;
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Closing datasets\n");
+
+    /* Close the datasets */
+    for(u = 0; u < NLEVELS; u++)
+        for(v = 0; v < symbol_count[u]; v++)
+            if(H5Dclose(symbol_info[u][v].dsid) < 0)
+                return -1;
+
+    return 0;
+}
+
+static void
+usage(void)
+{
+    printf("\n");
+    printf("Usage error!\n");
+    printf("\n");
+    printf("Usage: swmr_writer [-q] [-o] [-f <# of records to write between flushing\n");
+    printf("    file contents>] [-r <random seed>] <# of records>\n");
+    printf("\n");
+    printf("<# of records to write between flushing file contents> should be 0\n");
+    printf("(for no flushing) or between 1 and (<# of records> - 1).\n");
+    printf("\n");
+    printf("<# of records> must be specified.\n");
+    printf("\n");
+    printf("Defaults to verbose (no '-q' given), latest format when opening file (no '-o' given),\n");
+    printf("flushing every 10000 records ('-f 10000'), and will generate a random seed (no -r given).\n");
+    printf("\n");
+    HDexit(1);
+}
+
+int main(int argc, const char *argv[])
+{
+    hid_t fid;                  /* File ID for file opened */
+    long nrecords = 0;          /* # of records to append */
+    long flush_count = 10000;   /* # of records to write between flushing file */
+    hbool_t verbose = TRUE;     /* Whether to emit some informational messages */
+    FILE *verbose_file = NULL;  /* File handle for verbose output */
+    hbool_t old = FALSE;        /* Whether to use non-latest-format when opening file */
+    hbool_t use_seed = FALSE;   /* Set to TRUE if a seed was set on the command line */
+    unsigned random_seed = 0;   /* Random # seed */
+    unsigned u;                 /* Local index variable */
+    int temp;
+
+    /* Parse command line options */
+    if(argc < 2)
+        usage();
+    if(argc > 1) {
+        u = 1;
+        while(u < (unsigned)argc) {
+            if(argv[u][0] == '-') {
+                switch(argv[u][1]) {
+                    /* # of records to write between flushing file */
+                    case 'f':
+                        flush_count = HDatol(argv[u + 1]);
+                        if(flush_count < 0)
+                            usage();
+                        u += 2;
+                        break;
+
+                    /* Be quiet */
+                    case 'q':
+                        verbose = FALSE;
+                        u++;
+                        break;
+                    
+                    /* Random # seed */
+                    case 'r':
+                        use_seed = TRUE;
+                        temp = HDatoi(argv[u + 1]);
+                        random_seed = (unsigned)temp;
+                        u += 2;
+                        break;
+
+                    /* Use non-latest-format when opening file */
+                    case 'o':
+                        old = TRUE;
+                        u++;
+                        break;
+
+                    default:
+                        usage();
+                        break;
+                } /* end switch */
+            } /* end if */
+            else {
+                /* Get the number of records to append */
+                nrecords = HDatol(argv[u]);
+                if(nrecords <= 0)
+                    usage();
+
+                u++;
+            } /* end else */
+        } /* end while */
+    } /* end if */
+    if(nrecords <= 0)
+        usage();
+    if(flush_count >= nrecords)
+        usage();
+
+    /* Set the random seed */
+    if(!use_seed) {
+        struct timeval t;
+
+        HDgettimeofday(&t, NULL);
+        random_seed = (unsigned)(t.tv_usec);
+    } /* end if */
+    HDsrandom(random_seed);
+
+    /* Open output file */
+    if(verbose) {
+        char verbose_name[1024];
+
+        HDsnprintf(verbose_name, sizeof(verbose_name), "swmr_writer.out.%u", random_seed);
+        if(NULL == (verbose_file = HDfopen(verbose_name, "w"))) {
+            HDfprintf(stderr, "Can't open verbose output file!\n");
+            HDexit(1);
+        }
+    } /* end if */
+
+    /* Emit informational message */
+    if(verbose) {
+        HDfprintf(verbose_file, "Parameters:\n");
+        HDfprintf(verbose_file, "\t# of records between flushes = %ld\n", flush_count);
+        HDfprintf(verbose_file, "\t# of records to write = %ld\n", nrecords);
+    } /* end if */
+
+    /* ALWAYS emit the random seed for possible debugging */
+    HDfprintf(stdout, "Using writer random seed: %u\n", random_seed);
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Generating symbol names\n");
+
+    /* Generate dataset names */
+    if(generate_symbols() < 0)
+        return -1;
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Opening skeleton file: %s\n", FILENAME);
+
+    /* Open file skeleton */
+    if((fid = open_skeleton(FILENAME, verbose, verbose_file, random_seed, old)) < 0) {
+        HDfprintf(stderr, "Error opening skeleton file!\n");
+        HDexit(1);
+    } /* end if */
+
+    /* Send a message to indicate "H5Fopen" is complete--releasing the file lock */
+    h5_send_message(WRITER_MESSAGE, NULL, NULL);
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Adding records\n");
+
+    /* Append records to datasets */
+    if(add_records(fid, verbose, verbose_file, (unsigned long)nrecords, (unsigned long)flush_count) < 0) {
+        HDfprintf(stderr, "Error appending records to datasets!\n");
+        HDexit(1);
+    } /* end if */
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Releasing symbols\n");
+
+    /* Clean up the symbols */
+    if(shutdown_symbols() < 0) {
+        HDfprintf(stderr, "Error releasing symbols!\n");
+        HDexit(1);
+    } /* end if */
+
+    /* Emit informational message */
+    if(verbose)
+        HDfprintf(verbose_file, "Closing objects\n");
+
+    /* Close objects opened */
+    if(H5Fclose(fid) < 0) {
+        HDfprintf(stderr, "Error closing file!\n");
+        HDexit(1);
+    } /* end if */
+
+    return 0;
+}
+