[svn-r8989] Purpose:

    Backport feature

Description:
    Backport Kent's collective chunk I/O work to date into the release branch.

    Also, minor code cleanups, etc.

Platforms tested:
    FreeBSD 4.10 (sleipnir) w/parallel
    IRIX64 6.5 (modi4)
    h5committested

13 files changed, 366 insertions, 365 deletions

diff --git a/src/Dependencies b/src/Dependencies
index 80d76d4..0d4a162 100644
--- a/src/Dependencies
+++ b/src/Dependencies
@@ -430,6 +430,49 @@ H5Distore.lo: \
    $(srcdir)/H5MFprivate.h \
    $(srcdir)/H5MMprivate.h \
    $(srcdir)/H5Vprivate.h
+H5Dmpio.lo: \
+   $(srcdir)/H5Dmpio.c \
+   $(srcdir)/H5private.h \
+   $(srcdir)/H5public.h \
+   H5pubconf.h \
+   $(srcdir)/H5api_adpt.h \
+   $(srcdir)/H5MPprivate.h \
+   $(srcdir)/H5Dpkg.h \
+   $(srcdir)/H5Dprivate.h \
+   $(srcdir)/H5Dpublic.h \
+   $(srcdir)/H5Ipublic.h \
+   $(srcdir)/H5FDprivate.h \
+   $(srcdir)/H5FDpublic.h \
+   $(srcdir)/H5Fpublic.h \
+   $(srcdir)/H5FDmpi.h \
+   $(srcdir)/H5FDmpio.h \
+   $(srcdir)/H5FDmpiposix.h \
+   $(srcdir)/H5Oprivate.h \
+   $(srcdir)/H5Opublic.h \
+   $(srcdir)/H5Spublic.h \
+   $(srcdir)/H5HGprivate.h \
+   $(srcdir)/H5HGpublic.h \
+   $(srcdir)/H5Fprivate.h \
+   $(srcdir)/H5RCprivate.h \
+   $(srcdir)/H5Tprivate.h \
+   $(srcdir)/H5Tpublic.h \
+   $(srcdir)/H5MMpublic.h \
+   $(srcdir)/H5Gprivate.h \
+   $(srcdir)/H5Gpublic.h \
+   $(srcdir)/H5Bprivate.h \
+   $(srcdir)/H5Bpublic.h \
+   $(srcdir)/H5ACprivate.h \
+   $(srcdir)/H5ACpublic.h \
+   $(srcdir)/H5RSprivate.h \
+   $(srcdir)/H5Rprivate.h \
+   $(srcdir)/H5Rpublic.h \
+   $(srcdir)/H5Zprivate.h \
+   $(srcdir)/H5Zpublic.h \
+   $(srcdir)/H5Sprivate.h \
+   $(srcdir)/H5Pprivate.h \
+   $(srcdir)/H5Ppublic.h \
+   $(srcdir)/H5Eprivate.h \
+   $(srcdir)/H5Epublic.h
 H5Dseq.lo: \
    $(srcdir)/H5Dseq.c \
    $(srcdir)/H5private.h \
@@ -2468,8 +2511,8 @@ H5S.lo: \
    $(srcdir)/H5Eprivate.h \
    $(srcdir)/H5Epublic.h \
    $(srcdir)/H5Ipublic.h \
-   $(srcdir)/H5Iprivate.h \
    $(srcdir)/H5FLprivate.h \
+   $(srcdir)/H5Iprivate.h \
    $(srcdir)/H5MMprivate.h \
    $(srcdir)/H5MMpublic.h \
    $(srcdir)/H5Oprivate.h \
@@ -2602,46 +2645,43 @@ H5Smpio.lo: \
    H5pubconf.h \
    $(srcdir)/H5api_adpt.h \
    $(srcdir)/H5MPprivate.h \
-   $(srcdir)/H5Eprivate.h \
-   $(srcdir)/H5Epublic.h \
+   $(srcdir)/H5Dprivate.h \
+   $(srcdir)/H5Dpublic.h \
    $(srcdir)/H5Ipublic.h \
-   $(srcdir)/H5Fpkg.h \
-   $(srcdir)/H5Fprivate.h \
-   $(srcdir)/H5Fpublic.h \
-   $(srcdir)/H5FDpublic.h \
-   $(srcdir)/H5Bpublic.h \
-   $(srcdir)/H5FOprivate.h \
-   $(srcdir)/H5TBprivate.h \
-   $(srcdir)/H5Gprivate.h \
-   $(srcdir)/H5Gpublic.h \
-   $(srcdir)/H5Opublic.h \
-   $(srcdir)/H5Bprivate.h \
-   $(srcdir)/H5ACprivate.h \
-   $(srcdir)/H5ACpublic.h \
-   $(srcdir)/H5RCprivate.h \
-   $(srcdir)/H5RSprivate.h \
    $(srcdir)/H5FDprivate.h \
+   $(srcdir)/H5FDpublic.h \
+   $(srcdir)/H5Fpublic.h \
    $(srcdir)/H5FDmpi.h \
    $(srcdir)/H5FDmpio.h \
    $(srcdir)/H5FDmpiposix.h \
-   $(srcdir)/H5Iprivate.h \
-   $(srcdir)/H5Pprivate.h \
-   $(srcdir)/H5Ppublic.h \
-   $(srcdir)/H5Dpublic.h \
-   $(srcdir)/H5MMpublic.h \
-   $(srcdir)/H5Zpublic.h \
    $(srcdir)/H5Oprivate.h \
+   $(srcdir)/H5Opublic.h \
    $(srcdir)/H5Spublic.h \
    $(srcdir)/H5HGprivate.h \
    $(srcdir)/H5HGpublic.h \
+   $(srcdir)/H5Fprivate.h \
+   $(srcdir)/H5RCprivate.h \
    $(srcdir)/H5Tprivate.h \
    $(srcdir)/H5Tpublic.h \
+   $(srcdir)/H5MMpublic.h \
+   $(srcdir)/H5Gprivate.h \
+   $(srcdir)/H5Gpublic.h \
+   $(srcdir)/H5Bprivate.h \
+   $(srcdir)/H5Bpublic.h \
+   $(srcdir)/H5ACprivate.h \
+   $(srcdir)/H5ACpublic.h \
+   $(srcdir)/H5RSprivate.h \
    $(srcdir)/H5Rprivate.h \
    $(srcdir)/H5Rpublic.h \
    $(srcdir)/H5Zprivate.h \
+   $(srcdir)/H5Zpublic.h \
+   $(srcdir)/H5Eprivate.h \
+   $(srcdir)/H5Epublic.h \
+   $(srcdir)/H5Iprivate.h \
+   $(srcdir)/H5Pprivate.h \
+   $(srcdir)/H5Ppublic.h \
    $(srcdir)/H5Spkg.h \
-   $(srcdir)/H5Sprivate.h \
-   $(srcdir)/H5Dprivate.h
+   $(srcdir)/H5Sprivate.h
 H5Snone.lo: \
    $(srcdir)/H5Snone.c \
    $(srcdir)/H5private.h \
diff --git a/src/H5Dio.c b/src/H5Dio.c
index 32e6a28..b59a11f 100644
--- a/src/H5Dio.c
+++ b/src/H5Dio.c
@@ -21,7 +21,6 @@
 #include "H5private.h"		/* Generic Functions			*/
 #include "H5Dpkg.h"		/* Dataset functions			*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
-#include "H5FDprivate.h"	/* File drivers				*/
 #include "H5FLprivate.h"	/* Free Lists                           */
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5MMprivate.h"	/* Memory management			*/
@@ -644,6 +643,8 @@ H5D_read(H5D_t *dataset, hid_t mem_type_id, const H5S_t *mem_space,
     hbool_t     use_par_opt_io=FALSE;   /* Whether the 'optimized' I/O routines with be parallel */
 #ifdef H5_HAVE_PARALLEL
     hbool_t     xfer_mode_changed=FALSE;    /* Whether the transfer mode was changed */
+    int         prop_value,new_value;
+    htri_t      check_prop;
 #endif /*H5_HAVE_PARALLEL*/
     H5D_dxpl_cache_t _dxpl_cache;       /* Data transfer property cache buffer */
     H5D_dxpl_cache_t *dxpl_cache=&_dxpl_cache;   /* Data transfer property cache */
@@ -756,10 +757,33 @@ H5D_read(H5D_t *dataset, hid_t mem_type_id, const H5S_t *mem_space,
     } /* end switch */
 
     /* Get dataspace functions */
-    if (NULL==(sconv=H5S_find(mem_space, file_space, sconv_flags, &use_par_opt_io)))
+    if (NULL==(sconv=H5S_find(dataset->ent.file, mem_space, file_space, sconv_flags, &use_par_opt_io, &dataset->layout)))
         HGOTO_ERROR (H5E_DATASET, H5E_UNSUPPORTED, FAIL, "unable to convert from file to memory data space")
 
 #ifdef H5_HAVE_PARALLEL
+#ifdef H5_HAVE_INSTRUMENTED_LIBRARY
+    /**** Test for collective chunk IO
+          notice the following code should be removed after 
+          a more general collective chunk IO algorithm is applied.
+    */
+
+    if(dataset->layout.type == H5D_CHUNKED) { /*only check for chunking storage */
+        check_prop = H5Pexist(dxpl_id,H5D_XFER_COLL_CHUNK_NAME);
+        if(check_prop < 0) 
+            HGOTO_ERROR(H5E_PLIST, H5E_UNSUPPORTED, FAIL, "unable to check property list");
+        if(check_prop > 0) {
+            if(H5Pget(dxpl_id,H5D_XFER_COLL_CHUNK_NAME,&prop_value)<0) 
+                HGOTO_ERROR(H5E_PLIST, H5E_UNSUPPORTED, FAIL, "unable to get property value"); 
+            if(!use_par_opt_io) {
+                new_value = 0;
+                if(H5Pset(dxpl_id,H5D_XFER_COLL_CHUNK_NAME,&new_value)<0)
+                    HGOTO_ERROR(H5E_PLIST, H5E_UNSUPPORTED, FAIL, "unable to set property value");
+            }
+        }
+    }
+    /* end Test for collective chunk IO */
+#endif /* H5_HAVE_INSTRUMENTED_LIBRARY */
+
     /* Don't reset the transfer mode if we can't or won't use it */
     if(!use_par_opt_io || !H5T_path_noop(tpath))
         H5D_io_assist_mpio(dxpl_id, dxpl_cache, &xfer_mode_changed);
@@ -846,6 +870,8 @@ H5D_write(H5D_t *dataset, hid_t mem_type_id, const H5S_t *mem_space,
     hbool_t     use_par_opt_io=FALSE;   /* Whether the 'optimized' I/O routines with be parallel */
 #ifdef H5_HAVE_PARALLEL
     hbool_t     xfer_mode_changed=FALSE;    /* Whether the transfer mode was changed */
+    int         prop_value,new_value;
+    htri_t      check_prop;
 #endif /*H5_HAVE_PARALLEL*/
     H5D_dxpl_cache_t _dxpl_cache;       /* Data transfer property cache buffer */
     H5D_dxpl_cache_t *dxpl_cache=&_dxpl_cache;   /* Data transfer property cache */
@@ -978,10 +1004,33 @@ H5D_write(H5D_t *dataset, hid_t mem_type_id, const H5S_t *mem_space,
     } /* end switch */
 
     /* Get dataspace functions */
-    if (NULL==(sconv=H5S_find(mem_space, file_space, sconv_flags, &use_par_opt_io)))
+    if (NULL==(sconv=H5S_find(dataset->ent.file, mem_space, file_space, sconv_flags, &use_par_opt_io, &dataset->layout)))
 	HGOTO_ERROR (H5E_DATASET, H5E_UNSUPPORTED, FAIL, "unable to convert from memory to file data space")
         
 #ifdef H5_HAVE_PARALLEL
+#ifdef H5_HAVE_INSTRUMENTED_LIBRARY
+    /**** Test for collective chunk IO
+          notice the following code should be removed after 
+          a more general collective chunk IO algorithm is applied.
+    */
+
+     if(dataset->layout.type == H5D_CHUNKED) { /*only check for chunking storage */
+         
+       check_prop = H5Pexist(dxpl_id,H5D_XFER_COLL_CHUNK_NAME);
+       if(check_prop < 0) 
+          HGOTO_ERROR(H5E_PLIST, H5E_UNSUPPORTED, FAIL, "unable to check property list");
+       if(check_prop > 0) {
+         if(H5Pget(dxpl_id,H5D_XFER_COLL_CHUNK_NAME,&prop_value)<0) 
+           HGOTO_ERROR(H5E_PLIST, H5E_UNSUPPORTED, FAIL, "unable to get property value"); 
+         if(!use_par_opt_io) {
+           new_value = 0;
+           if(H5Pset(dxpl_id,H5D_XFER_COLL_CHUNK_NAME,&new_value)<0)
+             HGOTO_ERROR(H5E_PLIST, H5E_UNSUPPORTED, FAIL, "unable to set property value");
+         }
+       }
+     }
+#endif /* H5_HAVE_INSTRUMENTED_LIBRARY */
+
     /* Don't reset the transfer mode if we can't or won't use it */
     if(!use_par_opt_io || !H5T_path_noop(tpath))
         H5D_io_assist_mpio(dxpl_id, dxpl_cache, &xfer_mode_changed);
@@ -2494,7 +2543,7 @@ H5D_create_chunk_map(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *file_sp
         } /* end if */
     } /* end else */
 
-#ifdef QAK 
+#ifdef QAK
 {
     int mpi_rank;
     double time;
diff --git a/src/H5Distore.c b/src/H5Distore.c
index 136ed69..daa2582 100644
--- a/src/H5Distore.c
+++ b/src/H5Distore.c
@@ -146,8 +146,6 @@ typedef struct H5D_istore_ud1_t {
 #define H5D_HASH(D,ADDR) H5F_addr_hash(ADDR,(D)->cache.chunk.nslots)
 
 /* Private prototypes */
-static haddr_t H5D_istore_get_addr(H5F_t *f, hid_t dxpl_id, const H5O_layout_t *layout,
-    const hssize_t offset[], H5D_istore_ud1_t *_udata);
 static void *H5D_istore_chunk_alloc(size_t size, const H5O_pline_t *pline);
 static void *H5D_istore_chunk_xfree(void *chk, const H5O_pline_t *pline);
 static herr_t H5D_istore_shared_free (void *page);
@@ -2164,7 +2162,7 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-static haddr_t
+haddr_t
 H5D_istore_get_addr(H5F_t *f, hid_t dxpl_id, const H5O_layout_t *layout,
 		    const hssize_t offset[], H5D_istore_ud1_t *_udata)
 {
diff --git a/src/H5Dmpio.c b/src/H5Dmpio.c
index 581a20a..e8da931 100644
--- a/src/H5Dmpio.c
+++ b/src/H5Dmpio.c
@@ -39,6 +39,10 @@
 
 #ifdef H5_HAVE_PARALLEL
 
+/* Interface initialization */
+#define INTERFACE_INIT  NULL
+static int             interface_initialize_g = 0;
+
 static herr_t
 H5D_mpio_spaces_xfer(H5F_t *f, const H5D_t *dset, size_t elmt_size,
                      const H5S_t *file_space, const H5S_t *mem_space,
@@ -219,11 +223,12 @@ H5D_mpio_spaces_read(H5F_t *f, const H5D_dxpl_cache_t UNUSED *dxpl_cache, hid_t
 {
     herr_t ret_value;
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5D_mpio_spaces_read);
+    FUNC_ENTER_NOAPI(H5D_mpio_spaces_read, FAIL);
 
     ret_value = H5D_mpio_spaces_xfer(f, dset, elmt_size, file_space,
         mem_space, dxpl_id, buf, store, 0/*read*/);
 
+done:
     FUNC_LEAVE_NOAPI(ret_value);
 } /* end H5D_mpio_spaces_read() */
 
@@ -257,12 +262,13 @@ H5D_mpio_spaces_write(H5F_t *f, const H5D_dxpl_cache_t UNUSED *dxpl_cache, hid_t
 {
     herr_t ret_value;
 
-    FUNC_ENTER_NOAPI_NOFUNC(H5D_mpio_spaces_write);
+    FUNC_ENTER_NOAPI(H5D_mpio_spaces_write, FAIL);
 
     /*OKAY: CAST DISCARDS CONST QUALIFIER*/
     ret_value = H5D_mpio_spaces_xfer(f, dset, elmt_size, file_space,
         mem_space, dxpl_id, (void*)buf, store, 1/*write*/);
 
+done:
     FUNC_LEAVE_NOAPI(ret_value);
 } /* end H5D_mpio_spaces_write() */
 #endif  /* H5_HAVE_PARALLEL */
diff --git a/src/H5Dpkg.h b/src/H5Dpkg.h
index e1d4b71..30183c3 100644
--- a/src/H5Dpkg.h
+++ b/src/H5Dpkg.h
@@ -33,7 +33,7 @@
 /* Other private headers needed by this file */
 #include "H5Gprivate.h"		/* Groups 			  	*/
 #include "H5Oprivate.h"		/* Object headers		  	*/
-#include "H5Sprivate.h"		/* Dataspace functions			*/
+#include "H5Sprivate.h"		/* Dataspaces 				*/
 #include "H5Tprivate.h"		/* Datatype functions			*/
 
 /**************************/
diff --git a/src/H5Dprivate.h b/src/H5Dprivate.h
index 163c1a6..f8fef09 100644
--- a/src/H5Dprivate.h
+++ b/src/H5Dprivate.h
@@ -154,6 +154,12 @@
 #define H5D_XFER_FILTER_CB_NAME       "filter_cb"
 #define H5D_XFER_FILTER_CB_SIZE       sizeof(H5Z_cb_t)
 #define H5D_XFER_FILTER_CB_DEF        {NULL,NULL}
+#ifdef H5_HAVE_INSTRUMENTED_LIBRARY
+/* Definitions for collective chunk I/O property */
+#define H5D_XFER_COLL_CHUNK_NAME       "coll_chunk"
+#define H5D_XFER_COLL_CHUNK_SIZE       sizeof(unsigned)
+#define H5D_XFER_COLL_CHUNK_DEF        1
+#endif /* H5_HAVE_INSTRUMENTED_LIBRARY */
 
 /****************************/
 /* Library Private Typedefs */
@@ -247,6 +253,9 @@ H5_DLL ssize_t H5D_compact_writevv(H5F_t *f, hid_t dxpl_id, H5D_t *dset,
     size_t mem_max_nseq, size_t *mem_curr_seq, size_t mem_size_arr[], hsize_t mem_offset_arr[], 
     const void *buf);
 
+/* forward reference for collective-chunk IO use */
+struct H5D_istore_ud1_t; /*define at H5Distore.c*/
+
 /* Functions that operate on indexed storage */
 H5_DLL herr_t H5D_istore_delete(H5F_t *f, hid_t dxpl_id,
     const H5O_layout_t *layout);
@@ -260,7 +269,29 @@ H5_DLL ssize_t H5D_istore_writevv(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache,
     size_t chunk_max_nseq, size_t *chunk_curr_seq, size_t chunk_len_arr[], hsize_t chunk_offset_arr[],
     size_t mem_max_nseq, size_t *mem_curr_seq, size_t mem_len_arr[], hsize_t mem_offset_arr[],
     const void *buf);
+H5_DLL haddr_t H5D_istore_get_addr(H5F_t *f, hid_t dxpl_id, 
+    const H5O_layout_t *layout, const hssize_t offset[], 
+    struct H5D_istore_ud1_t *_udata);
 H5_DLL herr_t H5D_istore_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE * stream,
 				int indent, int fwidth, int ndims);
 
+#ifdef H5_HAVE_PARALLEL
+/* Forward references */
+struct H5S_t;
+
+/* MPI-IO function to read directly from app buffer to file rky980813 */
+H5_DLL herr_t H5D_mpio_spaces_read(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id,
+    H5D_t *dset, const H5D_storage_t *store,
+    size_t nelmts, size_t elmt_size,
+    const struct H5S_t *file_space, const struct H5S_t *mem_space,
+    void *buf/*out*/);
+
+/* MPI-IO function to write directly from app buffer to file rky980813 */
+H5_DLL herr_t H5D_mpio_spaces_write(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id,
+    H5D_t *dset, const H5D_storage_t *store,
+    size_t nelmts, size_t elmt_size,
+    const struct H5S_t *file_space, const struct H5S_t *mem_space,
+    const void *buf);
+#endif /* H5_HAVE_PARALLEL */
+
 #endif
diff --git a/src/H5S.c b/src/H5S.c
index 5c42787..3ad61f8 100644
--- a/src/H5S.c
+++ b/src/H5S.c
@@ -14,14 +14,18 @@
 
 #define H5S_PACKAGE		/*suppress error about including H5Spkg	  */
 
+/* Pablo information */
+/* (Put before include files to avoid problems with inline functions) */
+#define PABLO_MASK	H5S_mask
+
 #define _H5S_IN_H5S_C
-#include "H5private.h"		/* Generic Functions			  */
-#include "H5Eprivate.h"		/* Error handling		  */
-#include "H5Iprivate.h"		/* ID Functions		  */
-#include "H5FLprivate.h"	/* Free Lists	  */
-#include "H5MMprivate.h"	/* Memory Management functions		  */
-#include "H5Oprivate.h"		/* object headers		  */
-#include "H5Spkg.h"		/* Dataspace functions			  */
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5FLprivate.h"	/* Free lists                           */
+#include "H5Iprivate.h"		/* IDs			  		*/
+#include "H5MMprivate.h"	/* Memory management			*/
+#include "H5Oprivate.h"		/* Object headers		  	*/
+#include "H5Spkg.h"		/* Dataspaces 				*/
 
 /* Local static function prototypes */
 static H5S_t * H5S_create(H5S_class_t type);
@@ -30,7 +34,6 @@ static herr_t H5S_set_extent_simple (H5S_t *space, unsigned rank,
 static htri_t H5S_is_simple(const H5S_t *sdim);
 
 /* Interface initialization */
-#define PABLO_MASK	H5S_mask
 #define INTERFACE_INIT	H5S_init_interface
 static int		interface_initialize_g = 0;
 static herr_t		H5S_init_interface(void);
@@ -1403,7 +1406,12 @@ done:
  *-------------------------------------------------------------------------
  */
 H5S_conv_t *
-H5S_find (const H5S_t *mem_space, const H5S_t *file_space, unsigned
+H5S_find (const H5F_t 
+#ifndef H5_HAVE_PARALLEL
+UNUSED
+#endif/* H5_HAVE_PARALLEL*/
+*file,
+const H5S_t *mem_space, const H5S_t *file_space, unsigned
 #ifndef H5_HAVE_PARALLEL
 UNUSED
 #endif /* H5_HAVE_PARALLEL */
@@ -1411,7 +1419,13 @@ flags, hbool_t
 #ifndef H5_HAVE_PARALLEL
 UNUSED
 #endif /* H5_HAVE_PARALLEL */
-*use_par_opt_io)
+*use_par_opt_io,
+#ifndef H5_HAVE_PARALLEL
+UNUSED
+#endif
+const H5O_layout_t *layout
+
+)
 {
     H5S_conv_t	*path=NULL;  /* Space conversion path */
 #ifdef H5_HAVE_PARALLEL
@@ -1441,15 +1455,15 @@ UNUSED
             /*
              * Check if we can set direct MPI-IO read/write functions
              */
-            opt=H5S_mpio_opt_possible(mem_space,file_space,flags);
+            opt=H5S_mpio_opt_possible(file,mem_space,file_space,flags,layout);
             if(opt==FAIL)
-                HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, NULL, "invalid check for contiguous dataspace ");
+                HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, NULL, "invalid check for direct IO dataspace ");
 
             /* Check if we can use the optimized parallel I/O routines */
             if(opt==TRUE) {
                 /* Set the pointers to the MPI-specific routines */
-                H5S_conv_g[i]->read = H5S_mpio_spaces_read;
-                H5S_conv_g[i]->write = H5S_mpio_spaces_write;
+                H5S_conv_g[i]->read = H5D_mpio_spaces_read;
+                H5S_conv_g[i]->write = H5D_mpio_spaces_write;
 
                 /* Indicate that the I/O will be parallel */
                 *use_par_opt_io=TRUE;
@@ -1483,15 +1497,15 @@ UNUSED
     /*
      * Check if we can set direct MPI-IO read/write functions
      */
-    opt=H5S_mpio_opt_possible(mem_space,file_space,flags);
+    opt=H5S_mpio_opt_possible(file,mem_space,file_space,flags,layout);
     if(opt==FAIL)
-        HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, NULL, "invalid check for contiguous dataspace ");
+        HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, NULL, "invalid check for direct IO dataspace ");
 
     /* Check if we can use the optimized parallel I/O routines */
     if(opt==TRUE) {
         /* Set the pointers to the MPI-specific routines */
-        path->read = H5S_mpio_spaces_read;
-        path->write = H5S_mpio_spaces_write;
+        path->read = H5D_mpio_spaces_read;
+        path->write = H5D_mpio_spaces_write;
 
         /* Indicate that the I/O will be parallel */
         *use_par_opt_io=TRUE;
diff --git a/src/H5Shyper.c b/src/H5Shyper.c
index f468db0..735a339 100644
--- a/src/H5Shyper.c
+++ b/src/H5Shyper.c
@@ -2295,7 +2295,7 @@ H5S_hyper_span_blocklist(H5S_hyper_span_info_t *spans, hssize_t start[], hssize_
     hsize_t u;                  /* Index variable */
     herr_t ret_value=SUCCEED;   /* return value */
 
-    FUNC_ENTER_NOAPI(H5S_hyper_span_blocklist, FAIL);
+    FUNC_ENTER_NOAPI_NOINIT(H5S_hyper_span_blocklist);
 
     /* Sanity checks */
     assert(spans);
@@ -2389,7 +2389,7 @@ done:
  EXAMPLES
  REVISION LOG
 --------------------------------------------------------------------------*/
-herr_t
+static herr_t
 H5S_get_select_hyper_blocklist(H5S_t *space, hbool_t internal, hsize_t startblock, hsize_t numblocks, hsize_t *buf)
 {
     H5S_hyper_dim_t *diminfo;               /* Alias for dataspace's diminfo information */
@@ -2621,16 +2621,15 @@ H5S_hyper_bounds_helper (const H5S_hyper_span_info_t *spans, const hssize_t *off
 
         /* Recurse if this node has down spans */
         if(curr->down!=NULL) {
-            if(H5S_hyper_bounds_helper(curr->down,offset,rank+1,start,end)<0) {
-                ret_value=FAIL;
-                break;
-            } /* end if */
+            if(H5S_hyper_bounds_helper(curr->down,offset,rank+1,start,end)<0)
+                HGOTO_DONE(FAIL)
         } /* end if */
 
         /* Advance to next node */
         curr=curr->next;
     } /* end while */
 
+done:
     FUNC_LEAVE_NOAPI(ret_value);
 } /* end H5S_hyper_bounds_helper() */
 
@@ -2913,7 +2912,7 @@ H5S_hyper_is_single(const H5S_t *space)
     H5S_hyper_span_info_t *spans;   /* Hyperslab span info node */
     H5S_hyper_span_t *span;         /* Hyperslab span node */
     unsigned u;                     /* index variable */
-    htri_t ret_value=FALSE;         /* return value */
+    htri_t ret_value=TRUE;         /* return value */
 
     FUNC_ENTER_NOAPI(H5S_hyper_is_single, FAIL);
 
@@ -2926,24 +2925,16 @@ H5S_hyper_is_single(const H5S_t *space)
          * block (i.e. count==1 in all dimensions)
          */
 
-        /* Initialize flags */
-        ret_value=TRUE;	/* assume true and reset if the dimensions don't match */
-
         /* Check for a single block */
         for(u=0; u<space->extent.rank; u++) {
-            if(space->select.sel_info.hslab->opt_diminfo[u].count>1) {
-                ret_value=FALSE;
-                break;
-            } /* end if */
+            if(space->select.sel_info.hslab->opt_diminfo[u].count>1)
+                HGOTO_DONE(FALSE)
         } /* end for */
     } /* end if */
     else {
         /*
          * For a region to be single, it must have only one block 
          */
-        /* Initialize flags */
-        ret_value=TRUE;	/* assume true and reset if the dimensions don't match */
-
         /* Get information for slowest changing information */
         spans=space->select.sel_info.hslab->span_lst;
 
@@ -2952,14 +2943,11 @@ H5S_hyper_is_single(const H5S_t *space)
             span=spans->head;
 
             /* Check that this is the only span and it spans the entire dimension */
-            if(span->next!=NULL) {
-                ret_value=FALSE;
-                break;
-            } /* end if */
-            else {
+            if(span->next!=NULL)
+                HGOTO_DONE(FALSE)
+            else
                 /* Walk down to the next span */
                 spans=span->down;
-            } /* end else */
         } /* end while */
     } /* end else */
 
@@ -3809,7 +3797,6 @@ static herr_t
 H5S_hyper_adjust_helper (H5S_hyper_span_info_t *spans, const hssize_t *offset)
 {
     H5S_hyper_span_t *span;     /* Pointer to current span in span tree */
-    herr_t ret_value=SUCCEED;   /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5S_hyper_adjust_helper);
 
@@ -3834,18 +3821,15 @@ H5S_hyper_adjust_helper (H5S_hyper_span_info_t *spans, const hssize_t *offset)
             assert(span->high>=0);
 
             /* Recursively adjust spans in next dimension down */
-            if(span->down!=NULL) {
-                if(H5S_hyper_adjust_helper(span->down,offset+1)<0)
-                    HGOTO_ERROR(H5E_DATASPACE, H5E_BADSELECT, FAIL, "can't perform hyperslab adjustment");
-            } /* end if */
+            if(span->down!=NULL)
+                H5S_hyper_adjust_helper(span->down,offset+1);
 
             /* Advance to next span in this dimension */
             span=span->next;
         } /* end while */
     } /* end if */
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(SUCCEED);
 }   /* H5S_hyper_adjust_helper() */
 
 
@@ -3924,7 +3908,6 @@ static herr_t
 H5S_hyper_move_helper (H5S_hyper_span_info_t *spans, const hssize_t *offset)
 {
     H5S_hyper_span_t *span;     /* Pointer to current span in span tree */
-    herr_t ret_value=SUCCEED;   /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5S_hyper_move_helper);
 
@@ -3949,18 +3932,15 @@ H5S_hyper_move_helper (H5S_hyper_span_info_t *spans, const hssize_t *offset)
             assert(span->low>=0);
 
             /* Recursively move spans in next dimension down */
-            if(span->down!=NULL) {
-                if(H5S_hyper_move_helper(span->down,offset+1)<0)
-                    HGOTO_ERROR(H5E_DATASPACE, H5E_BADSELECT, FAIL, "can't perform hyperslab movement");
-            } /* end if */
+            if(span->down!=NULL)
+                H5S_hyper_move_helper(span->down,offset+1);
 
             /* Advance to next span in this dimension */
             span=span->next;
         } /* end while */
     } /* end if */
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(SUCCEED);
 }   /* H5S_hyper_move_helper() */
 
 
@@ -5280,7 +5260,6 @@ H5S_hyper_rebuild (H5S_t *space)
     H5S_hyper_dim_t *app_diminfo;   /* "Application view" per-dimension for the selection */
     H5S_hyper_span_t *span;     /* Current hyperslab span */
     unsigned curr_dim;          /* Current dimension being worked on */
-    herr_t ret_value=SUCCEED;   /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5S_hyper_rebuild);
 
@@ -5321,7 +5300,7 @@ H5S_hyper_rebuild (H5S_t *space)
         space->select.sel_info.hslab->diminfo_valid=TRUE;
     } /* end if */
 
-    FUNC_LEAVE_NOAPI(ret_value);
+    FUNC_LEAVE_NOAPI(SUCCEED);
 }   /* H5S_hyper_rebuild() */
 
 
@@ -6828,14 +6807,14 @@ H5S_hyper_get_seq_list_opt(const H5S_t *space,H5S_sel_iter_t *iter,
  EXAMPLES
  REVISION LOG
 --------------------------------------------------------------------------*/
-herr_t
+static herr_t
 H5S_hyper_get_seq_list(const H5S_t *space, unsigned UNUSED flags, H5S_sel_iter_t *iter,
     size_t maxseq, size_t maxelem, size_t *nseq, size_t *nelem,
     hsize_t *off, size_t *len)
 {
     herr_t ret_value;      /* return value */
 
-    FUNC_ENTER_NOAPI (H5S_hyper_get_seq_list, FAIL);
+    FUNC_ENTER_NOAPI_NOINIT(H5S_hyper_get_seq_list);
 
     /* Check args */
     assert(space);
@@ -6855,7 +6834,6 @@ H5S_hyper_get_seq_list(const H5S_t *space, unsigned UNUSED flags, H5S_sel_iter_t
         /* Call the general sequence generator routine */
         ret_value=H5S_hyper_get_seq_list_gen(space,iter,maxseq,maxelem,nseq,nelem,off,len);
 
-done:
     FUNC_LEAVE_NOAPI(ret_value);
 } /* end H5S_hyper_get_seq_list() */
 
diff --git a/src/H5Smpio.c b/src/H5Smpio.c
index c8aab2d..bf8f717 100644
--- a/src/H5Smpio.c
+++ b/src/H5Smpio.c
@@ -21,7 +21,6 @@
  *		I didn't make them portable.
  */
 
-#define H5F_PACKAGE		/*suppress error about including H5Fpkg	  */
 #define H5S_PACKAGE		/*suppress error about including H5Spkg	  */
 
 /* Pablo information */
@@ -29,10 +28,12 @@
 #define PABLO_MASK	H5S_mpio_mask
 
 #include "H5private.h"		/* Generic Functions			*/
+#include "H5Dprivate.h"		/* Datasets				*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
-#include "H5Fpkg.h"		/* Files				*/
+#include "H5Fprivate.h"		/* File access				*/
 #include "H5FDprivate.h"	/* File drivers				*/
 #include "H5Iprivate.h"		/* IDs			  		*/
+#include "H5Oprivate.h"		/* Object headers		  	*/
 #include "H5Pprivate.h"         /* Property lists                       */
 #include "H5Spkg.h"		/* Dataspaces 				*/
 
@@ -63,17 +64,6 @@ H5S_mpio_hyper_type( const H5S_t *space, size_t elmt_size,
 		     size_t *count,
 		     hsize_t *extra_offset,
 		     hbool_t *is_derived_type );
-static herr_t
-H5S_mpio_space_type( const H5S_t *space, size_t elmt_size,
-		     /* out: */
-		     MPI_Datatype *new_type,
-		     size_t *count,
-		     hsize_t *extra_offset,
-		     hbool_t *is_derived_type );
-static herr_t
-H5S_mpio_spaces_xfer(H5F_t *f, const H5D_t *dset, size_t elmt_size,
-                     const H5S_t *file_space, const H5S_t *mem_space,
-                     hid_t dxpl_id, void *buf/*out*/, hbool_t do_write);
 
 
 /*-------------------------------------------------------------------------
@@ -522,7 +512,7 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
+herr_t
 H5S_mpio_space_type( const H5S_t *space, size_t elmt_size,
 		     /* out: */
 		     MPI_Datatype *new_type,
@@ -586,221 +576,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5S_mpio_spaces_xfer
- *
- * Purpose:	Use MPI-IO to transfer data efficiently
- *		directly between app buffer and file.
- *
- * Return:	non-negative on success, negative on failure.
- *
- * Programmer:	rky 980813
- *
- * Notes:
- *      For collective data transfer only since this would eventually call
- *      H5FD_mpio_setup to do setup to eveually call MPI_File_set_view in
- *      H5FD_mpio_read or H5FD_mpio_write.  MPI_File_set_view is a collective
- *      call.  Letting independent data transfer use this route would result in
- *      hanging.
- *
- *      The preconditions for calling this routine are located in the
- *      H5S_mpio_opt_possible() routine, which determines whether this routine
- *      can be called for a given dataset transfer.
- *
- * Modifications:
- *	rky 980918
- *	Added must_convert parameter to let caller know we can't optimize
- *	the xfer.
- *
- *	Albert Cheng, 001123
- *	Include the MPI_type freeing as part of cleanup code.
- *
- *      QAK - 2002/04/02
- *      Removed the must_convert parameter and move preconditions to
- *      H5S_mpio_opt_possible() routine
- *
- *      QAK - 2002/06/17
- *      Removed 'disp' parameter from H5FD_mpio_setup routine and use the
- *      address of the dataset in MPI_File_set_view() calls, as necessary.
- *
- *      QAK - 2002/06/18
- *      Removed 'dc_plist' parameter, since it was not used.  Also, switch to
- *      getting the 'extra_offset' setting for each selection.
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5S_mpio_spaces_xfer(H5F_t *f, const H5D_t *dset, size_t elmt_size,
-     const H5S_t *file_space, const H5S_t *mem_space,
-     hid_t dxpl_id, void *_buf /*out*/,
-     hbool_t do_write )
-{
-    haddr_t	 addr;                  /* Address of dataset (or selection) within file */
-    size_t	 mpi_buf_count, mpi_file_count;       /* Number of "objects" to transfer */
-    hsize_t	 mpi_buf_offset, mpi_file_offset;       /* Offset within dataset where selection (ie. MPI type) begins */
-    MPI_Datatype mpi_buf_type, mpi_file_type;   /* MPI types for buffer (memory) and file */
-    hbool_t	 mbt_is_derived=0,      /* Whether the buffer (memory) type is derived and needs to be free'd */
-		 mft_is_derived=0;      /* Whether the file type is derived and needs to be free'd */
-    hbool_t	 plist_is_setup=0;      /* Whether the dxpl has been customized */
-    uint8_t	*buf=(uint8_t *)_buf;   /* Alias for pointer arithmetic */
-    int         mpi_code;               /* MPI return code */
-    herr_t	 ret_value = SUCCEED;   /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT(H5S_mpio_spaces_xfer);
-
-    /* Check args */
-    assert (f);
-    assert (dset);
-    assert (file_space);
-    assert (mem_space);
-    assert (buf);
-    assert (IS_H5FD_MPIO(f));
-    /* Make certain we have the correct type of property list */
-    assert(TRUE==H5P_isa_class(dxpl_id,H5P_DATASET_XFER));
-
-    /* create the MPI buffer type */
-    if (H5S_mpio_space_type( mem_space, elmt_size,
-			       /* out: */
-			       &mpi_buf_type,
-			       &mpi_buf_count,
-			       &mpi_buf_offset,
-			       &mbt_is_derived )<0)
-    	HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL,"couldn't create MPI buf type");
-
-    /* create the MPI file type */
-    if ( H5S_mpio_space_type( file_space, elmt_size,
-			       /* out: */
-			       &mpi_file_type,
-			       &mpi_file_count,
-			       &mpi_file_offset,
-			       &mft_is_derived )<0)
-    	HGOTO_ERROR(H5E_DATASPACE, H5E_BADTYPE, FAIL,"couldn't create MPI file type");
-
-    addr = H5D_contig_get_addr(dset) + mpi_file_offset;
-#ifdef H5Smpi_DEBUG
-    HDfprintf(stderr, "spaces_xfer: relative addr=%a\n", addr );
-#endif
-
-    /*
-     * Pass buf type, file type to the file driver. Request an MPI type
-     * transfer (instead of an elementary byteblock transfer).
-     */
-    if(H5FD_mpi_setup_collective(dxpl_id, mpi_buf_type, mpi_file_type)<0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set MPI-I/O properties");
-    plist_is_setup=1;
-
-    /* Adjust the buffer pointer to the beginning of the selection */
-    buf+=mpi_buf_offset;
-
-    /* transfer the data */
-    if (do_write) {
-    	if (H5F_block_write(f, H5FD_MEM_DRAW, addr, mpi_buf_count, dxpl_id, buf) <0)
-	    HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL,"MPI write failed");
-    } else {
-    	if (H5F_block_read (f, H5FD_MEM_DRAW, addr, mpi_buf_count, dxpl_id, buf) <0)
-	    HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL,"MPI read failed");
-    }
-
-done:
-    /* Reset the dxpl settings */
-    if(plist_is_setup) {
-        if(H5FD_mpi_teardown_collective(dxpl_id)<0)
-    	    HDONE_ERROR(H5E_DATASPACE, H5E_CANTFREE, FAIL, "unable to reset dxpl values");
-    } /* end if */
-
-    /* free the MPI buf and file types */
-    if (mbt_is_derived) {
-	if (MPI_SUCCESS != (mpi_code= MPI_Type_free( &mpi_buf_type )))
-            HMPI_DONE_ERROR(FAIL, "MPI_Type_free failed", mpi_code);
-    }
-    if (mft_is_derived) {
-	if (MPI_SUCCESS != (mpi_code= MPI_Type_free( &mpi_file_type )))
-            HMPI_DONE_ERROR(FAIL, "MPI_Type_free failed", mpi_code);
-    }
-
-    FUNC_LEAVE_NOAPI(ret_value);
-} /* end H5S_mpio_spaces_xfer() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5S_mpio_spaces_read
- *
- * Purpose:	MPI-IO function to read directly from app buffer to file.
- *
- * Return:	non-negative on success, negative on failure.
- *
- * Programmer:	rky 980813
- *
- * Modifications:
- *
- * rky 980918
- * Added must_convert parameter to let caller know we can't optimize the xfer.
- *
- *      QAK - 2002/04/02
- *      Removed the must_convert parameter and move preconditions to
- *      H5S_mpio_opt_possible() routine
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5S_mpio_spaces_read(H5F_t *f, const H5D_dxpl_cache_t UNUSED *dxpl_cache, hid_t dxpl_id,
-    H5D_t *dset, const H5D_storage_t UNUSED *store,
-    size_t UNUSED nelmts, size_t elmt_size,
-    const H5S_t *file_space, const H5S_t *mem_space,
-    void *buf/*out*/)
-{
-    herr_t ret_value;
-
-    FUNC_ENTER_NOAPI(H5S_mpio_spaces_read, FAIL);
-
-    ret_value = H5S_mpio_spaces_xfer(f, dset, elmt_size, file_space,
-        mem_space, dxpl_id, buf, 0/*read*/);
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value);
-} /* end H5S_mpio_spaces_read() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5S_mpio_spaces_write
- *
- * Purpose:	MPI-IO function to write directly from app buffer to file.
- *
- * Return:	non-negative on success, negative on failure.
- *
- * Programmer:	rky 980813
- *
- * Modifications:
- *
- * rky 980918
- * Added must_convert parameter to let caller know we can't optimize the xfer.
- *
- *      QAK - 2002/04/02
- *      Removed the must_convert parameter and move preconditions to
- *      H5S_mpio_opt_possible() routine
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5S_mpio_spaces_write(H5F_t *f, const H5D_dxpl_cache_t UNUSED *dxpl_cache, hid_t dxpl_id,
-    H5D_t *dset, const H5D_storage_t UNUSED *store,
-    size_t UNUSED nelmts, size_t elmt_size,
-    const H5S_t *file_space, const H5S_t *mem_space,
-    const void *buf)
-{
-    herr_t ret_value;
-
-    FUNC_ENTER_NOAPI(H5S_mpio_spaces_write, FAIL);
-
-    /*OKAY: CAST DISCARDS CONST QUALIFIER*/
-    ret_value = H5S_mpio_spaces_xfer(f, dset, elmt_size, file_space,
-        mem_space, dxpl_id, (void*)buf, 1/*write*/);
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value);
-} /* end H5S_mpio_spaces_write() */
-
-
-/*-------------------------------------------------------------------------
  * Function:	H5S_mpio_opt_possible
  *
  * Purpose:	Checks if an direct I/O transfer is possible between memory and
@@ -817,7 +592,7 @@ done:
  *-------------------------------------------------------------------------
  */
 htri_t
-H5S_mpio_opt_possible( const H5S_t *mem_space, const H5S_t *file_space, const unsigned flags)
+H5S_mpio_opt_possible( const H5F_t *file, const H5S_t *mem_space, const H5S_t *file_space, const unsigned flags,const H5O_layout_t *layout)
 {
     htri_t c1,c2;               /* Flags whether a selection is optimizable */
     htri_t ret_value=TRUE;
@@ -849,12 +624,126 @@ H5S_mpio_opt_possible( const H5S_t *mem_space, const H5S_t *file_space, const un
     if (H5S_SEL_POINTS==H5S_GET_SELECT_TYPE(mem_space) || H5S_SEL_POINTS==H5S_GET_SELECT_TYPE(file_space))
         HGOTO_DONE(FALSE);
 
-    /* Dataset storage must be contiguous currently */
-    if ((flags&H5S_CONV_STORAGE_MASK)!=H5S_CONV_STORAGE_CONTIGUOUS)
+    /* Dataset storage must be contiguous or chunked */
+    if ((flags&H5S_CONV_STORAGE_MASK)!=H5S_CONV_STORAGE_CONTIGUOUS && 
+            (flags&H5S_CONV_STORAGE_MASK)!=H5S_CONV_STORAGE_CHUNKED)
         HGOTO_DONE(FALSE);
 
+    if ((flags&H5S_CONV_STORAGE_MASK)==H5S_CONV_STORAGE_CHUNKED) {
+        hsize_t chunk_dim[H5O_LAYOUT_NDIMS];        /* Chunk dimensions */
+        hssize_t startf[H5S_MAX_RANK],      /* Selection start bounds */
+            endf[H5S_MAX_RANK];     /* Selection end bounds */
+        unsigned dim_rankf;         /* Number of dimensions of file dataspace */
+        int pcheck_hyper,check_hyper,   /* Flags for checking if selection is in one chunk */
+            tnum_chunkf,            /* Number of chunks selection overlaps */
+            max_chunkf,             /* Maximum number of chunks selection overlaps */
+            min_chunkf,             /* Minimum number of chunks selection overlaps */
+            num_chunks_same;        /* Flag indicating whether all processes have the same # of chunks to operate on */
+        unsigned dim_chunks;        /* Temporary number of chunks in a dimension */
+        MPI_Comm comm;              /* MPI communicator for file */
+        int mpi_rank;               /* Rank in MPI communicator */
+        int mpi_code;               /* MPI return code */
+        unsigned u;                 /* Local index variable */
+
+        /* Getting MPI communicator and rank */
+        if((comm = H5F_mpi_get_comm(file))==MPI_COMM_NULL)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't retrieve MPI communicator")
+        if((mpi_rank = H5F_mpi_get_rank(file))<0)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTGET, FAIL, "can't retrieve MPI rank")
+
+      /* Currently collective chunking storage 
+	 inside HDF5 is supported for either one of the following two cases:
+	 1. All the hyperslabs for one process is inside one chunk.
+	 2. For single hyperslab selection, the number of chunks that covered 
+	    the single selection for all processes should be equal. 
+	    KY, 2004/7/14
+      */
+
+      /* Quincey, please read.
+	 This is maybe redundant, I think only when both memory and file space be SCALAR
+	 space, the collective IO can work. Otherwise, SELECT_POINT will be reached,collective
+	 IO shouldn't work.
+	 Please clarify and correct the code on the following,
+         Quincey said that it was probably okay if only one data space is SCALAR, 
+         Still keep the code here until we added more tests later.
+	 Kent */
+        if(H5S_SCALAR==mem_space->extent.type || H5S_SCALAR ==file_space->extent.type) {
+            if(!(H5S_SCALAR==mem_space->extent.type && H5S_SCALAR ==file_space->extent.type))
+                HGOTO_DONE(FALSE)
+            else
+                HGOTO_DONE(TRUE)
+        } /* end if */
+
+        dim_rankf = file_space->extent.rank;
+
+        if(H5S_SELECT_BOUNDS(file_space,startf,endf)==FAIL)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE,FAIL, "invalid check for single selection blocks");
+
+        for(u=0; u < layout->u.chunk.ndims; u++) 
+            chunk_dim[u] = layout->u.chunk.dim[u];
+
+        /* Case 1: check whether all hyperslab in this process is inside one chunk.
+           Note: we don't handle when starting point is less than zero since that may cover
+           two chunks. */
+
+        /*for file space checking*/
+        pcheck_hyper = 1;
+        for (u=0; u<dim_rankf; u++)
+            if(endf[u]/chunk_dim[u]!=startf[u]/chunk_dim[u]) {
+                pcheck_hyper = 0;
+                break;
+            }
+      
+        if (MPI_SUCCESS != (mpi_code= MPI_Reduce(&pcheck_hyper,&check_hyper,1,MPI_INT,MPI_LAND,0,comm)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_Reduce failed", mpi_code)
+        if (MPI_SUCCESS != (mpi_code= MPI_Bcast(&check_hyper,1,MPI_INT,0,comm)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_Bcast failed", mpi_code)
+
+        /*if check_hyper is true, condition for collective IO case is fulfilled, no
+         need to do further test. */
+        if(check_hyper)
+            HGOTO_DONE(TRUE); 
+    
+      /* Case 2:Check whether the number of chunks that covered the single hyperslab is the same.
+	 If not,no collective chunk IO. 
+	 KY, 2004/7/14
+      */
+	 
+        c1 = H5S_SELECT_IS_SINGLE(file_space);
+        c2 = H5S_SELECT_IS_SINGLE(mem_space);
+
+        if(c1==FAIL || c2 ==FAIL)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_BADRANGE, FAIL, "invalid check for single selection blocks");
+        if(c1==FALSE || c2 ==FALSE)
+            HGOTO_DONE(FALSE);
+
+        /* Compute the number of chunks covered by the selection on this process */
+        tnum_chunkf = 1;
+        for (u=0; u<dim_rankf; u++) {
+            dim_chunks = (endf[u]/chunk_dim[u]-startf[u]/chunk_dim[u])+1;
+            tnum_chunkf = dim_chunks*tnum_chunkf;
+        }
+
+        /* Determine the minimum and maximum # of chunks for all processes */
+        if (MPI_SUCCESS != (mpi_code= MPI_Reduce(&tnum_chunkf,&max_chunkf,1,MPI_INT,MPI_MAX,0,comm)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_Reduce failed", mpi_code)
+        if (MPI_SUCCESS != (mpi_code= MPI_Reduce(&tnum_chunkf,&min_chunkf,1,MPI_INT,MPI_MIN,0,comm)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_Reduce failed", mpi_code)
+  
+        /* Let the rank==0 process determine if the same number of chunks will be operated on by all processes */
+        if(mpi_rank == 0)
+            num_chunks_same = (max_chunkf==min_chunkf);
+                    
+        /* Broadcast the flag indicating the number of chunks are the same */
+        if (MPI_SUCCESS != (mpi_code= MPI_Bcast(&num_chunks_same,1,MPI_INT,0,comm)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_Bcast failed", mpi_code)
+
+        /* Can't handle case when number of chunks is different (yet) */
+        if(!num_chunks_same)
+            HGOTO_DONE(FALSE);
+    }
+
 done:
     FUNC_LEAVE_NOAPI(ret_value);
 } /* H5S_mpio_opt_possible() */
-
 #endif  /* H5_HAVE_PARALLEL */
diff --git a/src/H5Spkg.h b/src/H5Spkg.h
index 82bfec2..ce93770 100644
--- a/src/H5Spkg.h
+++ b/src/H5Spkg.h
@@ -224,24 +224,10 @@ H5_DLL herr_t H5S_extent_copy(H5S_extent_t *dst, const H5S_extent_t *src);
 /* Operations on selections */
 
 #ifdef H5_HAVE_PARALLEL
-/* MPI-IO function to read directly from app buffer to file rky980813 */
-H5_DLL herr_t H5S_mpio_spaces_read(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id,
-    H5D_t *dset, const H5D_storage_t *store,
-    size_t nelmts, size_t elmt_size,
-    const H5S_t *file_space, const H5S_t *mem_space,
-    void *buf/*out*/);
-
-/* MPI-IO function to write directly from app buffer to file rky980813 */
-H5_DLL herr_t H5S_mpio_spaces_write(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id,
-    H5D_t *dset, const H5D_storage_t *store,
-    size_t nelmts, size_t elmt_size,
-    const H5S_t *file_space, const H5S_t *mem_space,
-    const void *buf);
-
 /* MPI-IO function to check if a direct I/O transfer is possible between
  * memory and the file */
-H5_DLL htri_t H5S_mpio_opt_possible(const H5S_t *mem_space,
-                                     const H5S_t *file_space, const unsigned flags);
+H5_DLL htri_t H5S_mpio_opt_possible(const H5F_t *file, const H5S_t *mem_space,
+    const H5S_t *file_space, const unsigned flags, const H5O_layout_t *layout);
 
 #endif /* H5_HAVE_PARALLEL */
 
diff --git a/src/H5Sprivate.h b/src/H5Sprivate.h
index 7de895a..efa9b30 100644
--- a/src/H5Sprivate.h
+++ b/src/H5Sprivate.h
@@ -206,8 +206,8 @@ typedef struct H5S_conv_t {
 /* Operations on dataspaces */
 H5_DLL H5S_t *H5S_copy(const H5S_t *src, hbool_t share_selection);
 H5_DLL herr_t H5S_close(H5S_t *ds);
-H5_DLL H5S_conv_t *H5S_find(const H5S_t *mem_space, const H5S_t *file_space,
-                unsigned flags, hbool_t *use_par_opt_io);
+H5_DLL H5S_conv_t *H5S_find(const H5F_t *file,const H5S_t *mem_space, const H5S_t *file_space,
+                unsigned flags, hbool_t *use_par_opt_io,const H5O_layout_t *layout );
 H5_DLL H5S_class_t H5S_get_simple_extent_type(const H5S_t *ds);
 H5_DLL hssize_t H5S_get_simple_extent_npoints(const H5S_t *ds);
 H5_DLL hsize_t H5S_get_npoints_max(const H5S_t *ds);
@@ -287,8 +287,6 @@ H5_DLL herr_t H5S_select_elements (H5S_t *space, H5S_seloper_t op,
 /* Operations on hyperslab selections */
 H5_DLL herr_t H5S_select_hyperslab (H5S_t *space, H5S_seloper_t op, const hssize_t start[],
     const hsize_t *stride, const hsize_t count[], const hsize_t *block);
-H5_DLL herr_t H5S_get_select_hyper_blocklist(H5S_t *space, hbool_t internal,
-    hsize_t startblock, hsize_t numblocks, hsize_t *buf);
 H5_DLL herr_t H5S_hyper_add_span_element(H5S_t *space, unsigned rank,
     hssize_t *coords);
 H5_DLL herr_t H5S_hyper_reset_scratch(H5S_t *space);
@@ -314,6 +312,14 @@ H5_DLL herr_t H5S_select_iter_release(H5S_sel_iter_t *sel_iter);
 /* (Defined in H5S.c) */
 H5_DLLVAR hbool_t		H5S_mpi_opt_types_g;
 #endif /* _H5S_IN_H5S_C */
+
+H5_DLL herr_t
+H5S_mpio_space_type( const H5S_t *space, size_t elmt_size,
+     /* out: */
+     MPI_Datatype *new_type,
+     size_t *count,
+     hsize_t *extra_offset,
+     hbool_t *is_derived_type );
 #endif /* H5_HAVE_PARALLEL */
 
 #endif /* _H5Sprivate_H */
diff --git a/src/H5config.h.in b/src/H5config.h.in
index f91986b..365122d 100644
--- a/src/H5config.h.in
+++ b/src/H5config.h.in
@@ -7,6 +7,9 @@
 /* Define if `dev_t' is a scalar */
 #undef DEV_T_IS_SCALAR
 
+/* Define if gettimeofday() populates the tz pointer passed in */
+#undef GETTIMEOFDAY_GIVES_TZ
+
 /* Define if the __attribute__(()) extension is present */
 #undef HAVE_ATTRIBUTE
 
@@ -88,6 +91,10 @@
 /* Define to 1 if you have the <gpfs.h> header file. */
 #undef HAVE_GPFS_H
 
+/* Define if library will contain instrumentation to detect correct
+   optimization operation */
+#undef HAVE_INSTRUMENTED_LIBRARY
+
 /* Define to 1 if you have the <inttypes.h> header file. */
 #undef HAVE_INTTYPES_H
 
@@ -356,9 +363,6 @@
 /* Define if `__tm_gmtoff' is a member of `struct tm' */
 #undef HAVE___TM_GMTOFF
 
-/* Define if gettimeofday() populates the tz pointer passed in */
-#undef GETTIMEOFDAY_GIVES_TZ
-
 /* Define if your system's `MPI_File_set_size' function works for files over
    2GB. */
 #undef MPI_FILE_SET_SIZE_BIG
diff --git a/src/Makefile.in b/src/Makefile.in
index 96fe515..0458936 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -31,19 +31,19 @@ DISTCLEAN=libhdf5.settings
 
 ## Source and object files for the library (lexicographically)...
 LIB_SRC=H5.c H5A.c H5AC.c H5B.c H5D.c H5Dcontig.c H5Dcompact.c H5Dio.c        \
-        H5Distore.c H5Dseq.c H5Dtest.c H5E.c H5F.c H5FD.c H5FDcore.c          \
-        H5FDfamily.c H5FDgass.c H5FDlog.c H5FDmpi.c H5FDmpio.c H5FDmpiposix.c \
-        H5FDmulti.c H5FDsec2.c H5FDsrb.c H5FDstdio.c H5FDstream.c H5FL.c      \
-        H5FO.c H5FS.c H5G.c H5Gent.c H5Gnode.c H5Gstab.c H5HG.c H5HL.c H5HP.c \
-        H5I.c H5MF.c H5MM.c H5O.c H5Oattr.c H5Obogus.c H5Ocont.c H5Odtype.c   \
-        H5Oefl.c H5Ofill.c H5Olayout.c H5Omtime.c H5Oname.c H5Onull.c         \
-        H5Opline.c H5Osdspace.c H5Oshared.c H5Ostab.c H5P.c H5Pdcpl.c         \
-        H5Pdxpl.c H5Pfapl.c H5Pfcpl.c H5Ptest.c H5R.c H5RC.c H5RS.c H5S.c     \
-        H5Sall.c H5Shyper.c H5Smpio.c H5Snone.c H5Spoint.c H5Sselect.c        \
-        H5Stest.c H5ST.c H5T.c H5Tarray.c H5Tbit.c H5Tcommit.c H5Tcompound.c  \
-        H5Tconv.c H5Tcset.c H5Tenum.c H5Tfields.c H5Tfixed.c H5Tfloat.c       \
-        H5Tinit.c H5Tnative.c H5Toffset.c H5Topaque.c H5Torder.c H5Tpad.c     \
-        H5Tprecis.c H5Tstrpad.c H5Tvlen.c H5TB.c H5TS.c H5V.c H5Z.c           \
+        H5Distore.c H5Dmpio.c H5Dseq.c H5Dtest.c H5E.c H5F.c H5FD.c           \
+        H5FDcore.c H5FDfamily.c H5FDgass.c H5FDlog.c H5FDmpi.c H5FDmpio.c     \
+        H5FDmpiposix.c H5FDmulti.c H5FDsec2.c H5FDsrb.c H5FDstdio.c           \
+        H5FDstream.c H5FL.c H5FO.c H5FS.c H5G.c H5Gent.c H5Gnode.c H5Gstab.c  \
+        H5HG.c H5HL.c H5HP.c H5I.c H5MF.c H5MM.c H5O.c H5Oattr.c H5Obogus.c   \
+        H5Ocont.c H5Odtype.c H5Oefl.c H5Ofill.c H5Olayout.c H5Omtime.c        \
+        H5Oname.c H5Onull.c H5Opline.c H5Osdspace.c H5Oshared.c H5Ostab.c     \
+        H5P.c H5Pdcpl.c H5Pdxpl.c H5Pfapl.c H5Pfcpl.c H5Ptest.c H5R.c H5RC.c  \
+        H5RS.c H5S.c H5Sall.c H5Shyper.c H5Smpio.c H5Snone.c H5Spoint.c       \
+        H5Sselect.c H5Stest.c H5ST.c H5T.c H5Tarray.c H5Tbit.c H5Tcommit.c    \
+        H5Tcompound.c H5Tconv.c H5Tcset.c H5Tenum.c H5Tfields.c H5Tfixed.c    \
+        H5Tfloat.c H5Tinit.c H5Tnative.c H5Toffset.c H5Topaque.c H5Torder.c   \
+        H5Tpad.c H5Tprecis.c H5Tstrpad.c H5Tvlen.c H5TB.c H5TS.c H5V.c H5Z.c  \
         H5Zdeflate.c H5Zfletcher32.c H5Zshuffle.c H5Zszip.c
 
 LIB_OBJ=$(LIB_SRC:.c=.lo)