[svn-r712] Added temporary buffer support to several places in the library which were

calling malloc too often.  Also, added caching of hyperslab blocks, which
improves performance _significantly_ for hyperslab I/O.

15 files changed, 664 insertions, 276 deletions

diff --git a/src/.distdep b/src/.distdep
index 52a7f29..3da24b4 100644
--- a/src/.distdep
+++ b/src/.distdep
@@ -25,10 +25,7 @@ H5.o: \
    H5Gpublic.h \
    H5Oprivate.h \
    H5Opublic.h \
-   H5HGprivate.h \
-   H5HGpublic.h \
-   H5Tprivate.h \
-   H5Tpublic.h
+   H5HGprivate.h
 H5A.o: \
    H5A.c \
    H5private.h \
@@ -166,7 +163,9 @@ H5F.o: \
    H5Eprivate.h \
    H5Epublic.h \
    H5MMprivate.h \
-   H5MMpublic.h
+   H5MMpublic.h \
+   H5Pprivate.h \
+   H5Ppublic.h
 H5Farray.o: \
    H5Farray.c \
    H5private.h \
@@ -1140,8 +1139,4 @@ H5Z.o: \
    H5HGprivate.h \
    H5HGpublic.h \
    H5Tprivate.h \
-   H5Tpublic.h \
-   H5Sprivate.h \
-   H5Spublic.h \
-   H5Zprivate.h \
-   H5Zpublic.h
+   H5Tpublic.h
diff --git a/src/H5D.c b/src/H5D.c
index 5ad5145..02beee5 100644
--- a/src/H5D.c
+++ b/src/H5D.c
@@ -28,6 +28,7 @@ static char		RcsId[] = "@(#)$Revision$";
 #include <H5Oprivate.h>		/* Object headers		  	*/
 #include <H5Pprivate.h>		/* Property lists			*/
 #include <H5Sprivate.h>		/* Dataspace functions rky 980813       */
+#include <H5TBprivate.h>	/* Temporary buffers        */
 #include <H5Zprivate.h>		/* Data filters				*/
 
 #ifdef QAK
@@ -71,6 +72,12 @@ const H5D_xfer_t	H5D_xfer_dflt = {
     NULL,			/* Type conversion buffer or NULL	*/
     NULL, 			/* Background buffer or NULL		*/
     H5T_BKG_NO,			/* Type of background buffer needed	*/
+#ifndef HAVE_PARALLEL
+    1,              /* Cache the hyperslab blocks by default */
+#else /* HAVE_PARALLEL */
+    0,              /* Don't cache the hyperslab blocks by default (for parallel) */
+#endif /* HAVE_PARALLEL */
+    0,              /* Default to no upper limit on hyperslab block size to cache */
 #ifdef HAVE_PARALLEL
     H5D_XFER_DFLT,      	/* Independent data transfer      	*/
 #endif
@@ -1280,6 +1287,7 @@ H5D_read(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
     hsize_t		nelmts;			/*number of elements	*/
     size_t		smine_start;		/*strip mine start loc	*/
     size_t		n, smine_nelmts;	/*elements per strip	*/
+    hid_t       tconv_id=FAIL, bkg_id=FAIL;   /* Conversion buffer IDs */
     uint8		*tconv_buf = NULL;	/*data type conv buffer	*/
     uint8		*bkg_buf = NULL;	/*background buffer	*/
     H5T_conv_t		tconv_func = NULL;	/*conversion function	*/
@@ -1457,16 +1465,18 @@ H5D_read(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
         need_bkg = H5T_BKG_NO; /*never needed even if app says yes*/
     }
     if (NULL==(tconv_buf=xfer_parms->tconv_buf)) {
-	if (NULL==(tconv_buf = H5MM_malloc (target_size))) {
-	    HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL,
-			 "memory allocation failed for type conversion");
-	}
+        /* Allocate temporary buffer */
+        if (FAIL==(tconv_id = H5TB_get_buf (target_size,1,(void **)&tconv_buf))) {
+            HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL,
+                 "memory allocation failed for type conversion");
+        }
     }
     if (need_bkg && NULL==(bkg_buf=xfer_parms->bkg_buf)) {
-	if (NULL==(bkg_buf = H5MM_malloc (request_nelmts * dst_type_size))) {
-	    HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL,
-			 "memory allocation failed for background buffer");
-	}
+        /* Allocate temporary buffer */
+        if (FAIL==(bkg_id = H5TB_get_buf (request_nelmts*dst_type_size,1,(void **)&bkg_buf))) {
+            HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL,
+                 "memory allocation failed for type conversion");
+        }
     }
 
 #ifdef QAK
@@ -1497,7 +1507,7 @@ H5D_read(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
 			     &(dataset->create_parms->pline),
 			     &(dataset->create_parms->efl), src_type_size,
 			     file_space, &file_iter, smine_nelmts,
-			     xfer_parms->xfer_mode, tconv_buf/*out*/);
+			     xfer_parms, tconv_buf/*out*/);
 #ifdef H5S_DEBUG
 	H5_timer_end(&(sconv->stats[1].gath_timer), &timer);
 	sconv->stats[1].gath_nbytes += n * src_type_size;
@@ -1599,8 +1609,8 @@ H5D_read(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
 
     if (src_id >= 0) H5I_dec_ref(src_id);
     if (dst_id >= 0) H5I_dec_ref(dst_id);
-    if (tconv_buf && NULL==xfer_parms->tconv_buf) H5MM_xfree(tconv_buf);
-    if (bkg_buf && NULL==xfer_parms->bkg_buf) H5MM_xfree (bkg_buf);
+    if (tconv_buf && NULL==xfer_parms->tconv_buf) H5TB_release_buf(tconv_id);
+    if (bkg_buf && NULL==xfer_parms->bkg_buf) H5TB_release_buf (bkg_id);
     if (free_this_space) H5S_close (free_this_space);
     FUNC_LEAVE(ret_value);
 }
@@ -1636,6 +1646,7 @@ H5D_write(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
     hsize_t		nelmts;			/*total number of elmts	*/
     size_t		smine_start;		/*strip mine start loc	*/
     size_t		n, smine_nelmts;	/*elements per strip	*/
+    hid_t       tconv_id=FAIL, bkg_id=FAIL;   /* Conversion buffer IDs */
     uint8		*tconv_buf = NULL;	/*data type conv buffer	*/
     uint8		*bkg_buf = NULL;	/*background buffer	*/
     H5T_conv_t		tconv_func = NULL;	/*conversion function	*/
@@ -1821,16 +1832,18 @@ H5D_write(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
         need_bkg = H5T_BKG_NO; /*never needed even if app says yes*/
     }
     if (NULL==(tconv_buf=xfer_parms->tconv_buf)) {
-	if (NULL==(tconv_buf = H5MM_malloc (target_size))) {
-	    HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL,
-			 "memory allocation failed for type conversion");
-	}
+        /* Allocate temporary buffer */
+        if (FAIL==(tconv_id = H5TB_get_buf (target_size,1,(void **)&tconv_buf))) {
+            HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL,
+                 "memory allocation failed for type conversion");
+        }
     }
     if (need_bkg && NULL==(bkg_buf=xfer_parms->bkg_buf)) {
-	if (NULL==(bkg_buf = H5MM_malloc (request_nelmts * dst_type_size))) {
-	    HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL,
-			 "memory allocation failed for background buffer");
-	}
+        /* Allocate temporary buffer */
+        if (FAIL==(bkg_id = H5TB_get_buf (request_nelmts*dst_type_size,1,(void **)&bkg_buf))) {
+            HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL,
+                 "memory allocation failed for type conversion");
+        }
     }
 
 #ifdef QAK
@@ -1894,8 +1907,7 @@ H5D_write(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
 				 &(dataset->create_parms->pline),
 				 &(dataset->create_parms->efl), dst_type_size,
 				 file_space, &bkg_iter, smine_nelmts,
-				 xfer_parms->xfer_mode,
-				 bkg_buf/*out*/);
+				 xfer_parms, bkg_buf/*out*/);
 #ifdef H5S_DEBUG
 	    H5_timer_end(&(sconv->stats[0].bkg_timer), &timer);
 	    sconv->stats[0].bkg_nbytes += n * dst_type_size;
@@ -1923,6 +1935,9 @@ H5D_write(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL,
                 "data type conversion failed");
         }
+#ifdef QAK
+	printf("%s: check 6.3\n",FUNC);
+#endif
 
         /*
          * Scatter the data out to the file.
@@ -1934,7 +1949,10 @@ H5D_write(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
 				  &(dataset->create_parms->pline),
 				  &(dataset->create_parms->efl), dst_type_size,
 				  file_space, &file_iter, smine_nelmts,
-				  xfer_parms->xfer_mode, tconv_buf);
+				  xfer_parms, tconv_buf);
+#ifdef QAK
+	printf("%s: check 6.35\n",FUNC);
+#endif
 #ifdef H5S_DEBUG
 	H5_timer_end(&(sconv->stats[0].scat_timer), &timer);
 	sconv->stats[0].scat_nbytes += smine_nelmts * dst_type_size;
@@ -1945,6 +1963,9 @@ H5D_write(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
         }
     }
 
+#ifdef QAK
+	printf("%s: check 6.4\n",FUNC);
+#endif
     /*
      * Update modification time.  We have to do this explicitly because
      * writing to a dataset doesn't necessarily change the object header.
@@ -1965,8 +1986,8 @@ H5D_write(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
 
     if (src_id >= 0) H5I_dec_ref(src_id);
     if (dst_id >= 0) H5I_dec_ref(dst_id);
-    if (tconv_buf && NULL==xfer_parms->tconv_buf) H5MM_xfree(tconv_buf);
-    if (bkg_buf && NULL==xfer_parms->bkg_buf) H5MM_xfree (bkg_buf);
+    if (tconv_buf && NULL==xfer_parms->tconv_buf) H5TB_release_buf(tconv_id);
+    if (bkg_buf && NULL==xfer_parms->bkg_buf) H5TB_release_buf (bkg_id);
     if (free_this_space) H5S_close (free_this_space);
     FUNC_LEAVE(ret_value);
 }
diff --git a/src/H5Distore.c b/src/H5Distore.c
index 48ad749..aa7c266 100644
--- a/src/H5Distore.c
+++ b/src/H5Distore.c
@@ -1051,7 +1051,6 @@ H5F_istore_lock (H5F_t *f, const H5O_layout_t *layout,
     size_t		chunk_alloc=0;		/*allocated chunk size	*/
     herr_t		status;			/*func return status	*/
     void		*chunk=NULL;		/*the file chunk	*/
-    void		*temp=NULL;		/*temporary chunk buffer*/
     void		*ret_value=NULL;	/*return value		*/
     
     FUNC_ENTER (H5F_istore_lock, NULL);
@@ -1216,7 +1215,6 @@ H5F_istore_lock (H5F_t *f, const H5O_layout_t *layout,
     ret_value = chunk;
  done:
     if (!ret_value) H5MM_xfree (chunk);
-    H5MM_xfree (temp);
     FUNC_LEAVE (ret_value);
 }
 
diff --git a/src/H5Dprivate.h b/src/H5Dprivate.h
index 245ed58..5bc6920 100644
--- a/src/H5Dprivate.h
+++ b/src/H5Dprivate.h
@@ -55,6 +55,8 @@ typedef struct H5D_xfer_t {
     void		*tconv_buf;	/*type conversion buffer or null     */
     void		*bkg_buf;	/*background buffer or null	     */
     H5T_bkg_t		need_bkg;	/*type of background buffer needed   */
+    uintn       cache_hyper;    /* Whether to (try to) cache hyperslab blocks during I/O */
+    uintn       block_limit;    /* The largest hyperslab block to try to cache */
     H5D_transfer_t	xfer_mode;	/*independent or collective transfer */
 } H5D_xfer_t;
 
diff --git a/src/H5Fistore.c b/src/H5Fistore.c
index 48ad749..aa7c266 100644
--- a/src/H5Fistore.c
+++ b/src/H5Fistore.c
@@ -1051,7 +1051,6 @@ H5F_istore_lock (H5F_t *f, const H5O_layout_t *layout,
     size_t		chunk_alloc=0;		/*allocated chunk size	*/
     herr_t		status;			/*func return status	*/
     void		*chunk=NULL;		/*the file chunk	*/
-    void		*temp=NULL;		/*temporary chunk buffer*/
     void		*ret_value=NULL;	/*return value		*/
     
     FUNC_ENTER (H5F_istore_lock, NULL);
@@ -1216,7 +1215,6 @@ H5F_istore_lock (H5F_t *f, const H5O_layout_t *layout,
     ret_value = chunk;
  done:
     if (!ret_value) H5MM_xfree (chunk);
-    H5MM_xfree (temp);
     FUNC_LEAVE (ret_value);
 }
 
diff --git a/src/H5P.c b/src/H5P.c
index 93f5a02..99b4e67 100644
--- a/src/H5P.c
+++ b/src/H5P.c
@@ -2074,6 +2074,90 @@ H5Pget_buffer(hid_t plist_id, void **tconv/*out*/, void **bkg/*out*/)
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5Pset_hyper_cache
+ *
+ * Purpose:	Given a dataset transfer property list, indicate whether to cache
+ *      the hyperslab blocks during the I/O (which speeds things up) and the
+ *      maximum size of the hyperslab block to cache.  If a block is smaller
+ *      than to limit, it may still not be cached if no memory is available.
+ *      Setting the limit to 0 indicates no limitation on the size of block
+ *      to attempt to cache.
+ *
+ *      The default is to cache blocks with no limit on block size for serial
+ *          I/O and to not cache blocks for parallel I/O
+ *
+ * Return:	Success:	SUCCEED
+ *
+ *		Failure:	FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, September 21, 1998
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_hyper_cache(hid_t plist_id, unsigned cache, unsigned limit)
+{
+    H5D_xfer_t		*plist = NULL;
+    
+    FUNC_ENTER (H5Pset_hyper_cache, FAIL);
+
+    /* Check arguments */
+    if (H5P_DATASET_XFER != H5P_get_class (plist_id) ||
+	NULL == (plist = H5I_object (plist_id))) {
+	HRETURN_ERROR (H5E_ARGS, H5E_BADTYPE, FAIL,
+		       "not a dataset transfer property list");
+    }
+
+    /* Update property list */
+    plist->cache_hyper = (cache>0) ? 1 : 0;
+    plist->block_limit = limit;
+
+    FUNC_LEAVE (SUCCEED);
+} /* end H5P_set_hyper_cache() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5Pget_hyper_cache
+ *
+ * Purpose:	Reads values previously set with H5Pset_hyper_cache().
+ *
+ * Return:	Success:	SUCCEED
+ *
+ *		Failure:	FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, September 21, 1998
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pget_hyper_cache(hid_t plist_id, unsigned *cache/*out*/, unsigned *limit/*out*/)
+{
+    H5D_xfer_t		*plist = NULL;
+    
+    FUNC_ENTER (H5Pget_hyper_cache, 0);
+
+    /* Check arguments */
+    if (H5P_DATASET_XFER != H5P_get_class (plist_id) ||
+	NULL == (plist = H5I_object (plist_id))) {
+	HRETURN_ERROR (H5E_ARGS, H5E_BADTYPE, 0,
+		       "not a dataset transfer property list");
+    }
+
+    /* Return values */
+    if (cache) *cache = plist->cache_hyper;
+    if (limit) *limit = plist->block_limit;
+
+    FUNC_LEAVE (SUCCEED);
+} /* end H5Pget_hyper_cache() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5Pset_preserve
  *
  * Purpose:	When reading or writing compound data types and the
diff --git a/src/H5Ppublic.h b/src/H5Ppublic.h
index 028fa57..d82bb83 100644
--- a/src/H5Ppublic.h
+++ b/src/H5Ppublic.h
@@ -105,6 +105,8 @@ herr_t H5Pset_cache (hid_t plist_id, int mdc_nelmts, size_t rdcc_nbytes,
 		     double rdcc_w0);
 herr_t H5Pget_cache (hid_t plist_id, int *mdc_nelmts, size_t *rdcc_nbytes,
 		     double *rdcc_w0);
+herr_t H5Pset_hyper_cache(hid_t plist_id, unsigned cache, unsigned limit);
+herr_t H5Pget_hyper_cache(hid_t plist_id, unsigned *cache, unsigned *limit);
 
 #ifdef HAVE_PARALLEL
 herr_t H5Pset_mpi (hid_t plist_id, MPI_Comm comm, MPI_Info info);
diff --git a/src/H5Sall.c b/src/H5Sall.c
index 022170c..71d8181 100644
--- a/src/H5Sall.c
+++ b/src/H5Sall.c
@@ -11,6 +11,7 @@
 #include <H5Eprivate.h>
 #include <H5Sprivate.h>
 #include <H5Vprivate.h>
+#include <H5Dprivate.h>
 
 /* Interface initialization */
 #define PABLO_MASK      H5S_all_mask
@@ -26,14 +27,14 @@ static size_t H5S_all_fgath (H5F_t *f, const struct H5O_layout_t *layout,
 			     const struct H5O_efl_t *efl, size_t elmt_size,
 			     const H5S_t *file_space,
 			     H5S_sel_iter_t *file_iter, size_t nelmts,
-			     const H5D_transfer_t xfer_mode,
+			     const void *_xfer_parms,
 			     void *buf/*out*/);
 static herr_t H5S_all_fscat (H5F_t *f, const struct H5O_layout_t *layout,
 			     const struct H5O_pline_t *pline,
 			     const struct H5O_efl_t *efl, size_t elmt_size,
 			     const H5S_t *file_space,
 			     H5S_sel_iter_t *file_iter, size_t nelmts,
-			     const H5D_transfer_t xfer_mode,
+			     const void *_xfer_parms,
 			     const void *buf);
 static size_t H5S_all_mgath (const void *_buf, size_t elmt_size,
 			     const H5S_t *mem_space, H5S_sel_iter_t *mem_iter,
@@ -170,8 +171,9 @@ H5S_all_fgath (H5F_t *f, const struct H5O_layout_t *layout,
 	       const struct H5O_pline_t *pline, const struct H5O_efl_t *efl,
 	       size_t elmt_size, const H5S_t *file_space,
 	       H5S_sel_iter_t *file_iter, size_t nelmts,
-	       const H5D_transfer_t xfer_mode, void *_buf/*out*/)
+	       const void *_xfer_parms, void *_buf/*out*/)
 {
+    const H5D_xfer_t *xfer_parms=(const H5D_xfer_t *)_xfer_parms;   /* Coerce the type */
     hssize_t	file_offset[H5O_LAYOUT_NDIMS];	/*offset of slab in file*/
     hsize_t	hsize[H5O_LAYOUT_NDIMS];	/*size of hyperslab	*/
     hssize_t	zero[H5O_LAYOUT_NDIMS];		/*zero			*/
@@ -224,7 +226,7 @@ H5S_all_fgath (H5F_t *f, const struct H5O_layout_t *layout,
      * Gather from file.
      */
     if (H5F_arr_read (f, layout, pline, efl, hsize, hsize, zero, file_offset,
-		      xfer_mode, buf/*out*/)<0) {
+		      xfer_parms->xfer_mode, buf/*out*/)<0) {
 	HRETURN_ERROR (H5E_DATASPACE, H5E_READERROR, 0, "read error");
     }
 
@@ -260,8 +262,9 @@ H5S_all_fscat (H5F_t *f, const struct H5O_layout_t *layout,
 	       const struct H5O_pline_t *pline, const struct H5O_efl_t *efl,
 	       size_t elmt_size, const H5S_t *file_space,
 	       H5S_sel_iter_t *file_iter, size_t nelmts,
-	       const H5D_transfer_t xfer_mode, const void *_buf)
+	       const void *_xfer_parms, const void *_buf)
 {
+    const H5D_xfer_t *xfer_parms=(const H5D_xfer_t *)_xfer_parms;   /* Coerce the type */
     hssize_t	file_offset[H5O_LAYOUT_NDIMS];	/*offset of hyperslab	*/
     hsize_t	hsize[H5O_LAYOUT_NDIMS];	/*size of hyperslab	*/
     hssize_t	zero[H5O_LAYOUT_NDIMS];		/*zero vector		*/
@@ -310,7 +313,7 @@ H5S_all_fscat (H5F_t *f, const struct H5O_layout_t *layout,
      * Scatter to file.
      */
     if (H5F_arr_write (f, layout, pline, efl, hsize, hsize, zero,
-		       file_offset, xfer_mode, buf)<0) {
+		       file_offset, xfer_parms->xfer_mode, buf)<0) {
         HRETURN_ERROR (H5E_DATASPACE, H5E_WRITEERROR, FAIL, "write error");
     }
 
diff --git a/src/H5Shyper.c b/src/H5Shyper.c
index c59d38e..24fca4c 100644
--- a/src/H5Shyper.c
+++ b/src/H5Shyper.c
@@ -12,6 +12,8 @@
 #include <H5Sprivate.h>
 #include <H5Vprivate.h>
 #include <H5MMprivate.h>
+#include <H5TBprivate.h>
+#include <H5Dprivate.h>
 
 /* Interface initialization */
 #define PABLO_MASK      H5S_hyper_mask
@@ -29,7 +31,7 @@ typedef struct {
     const H5S_t *space;
     H5S_sel_iter_t *iter;
 	size_t nelmts;
-    H5D_transfer_t xfer_mode;
+    const H5D_xfer_t *xfer_parms;
     const void *src;
     void *dst;
     H5S_hyper_bound_t **lo_bounds;
@@ -39,7 +41,7 @@ typedef struct {
 /* Static function prototypes */
 static intn H5S_hyper_bsearch(hssize_t size, H5S_hyper_bound_t *barr,
 			      size_t count);
-static H5S_hyper_region_t *
+static hid_t
 H5S_hyper_get_regions (size_t *num_regions, intn dim, size_t bound_count,
 		       H5S_hyper_bound_t **lo_bounds,
 		       H5S_hyper_bound_t **hi_bounds, hssize_t *pos,
@@ -56,14 +58,14 @@ static size_t H5S_hyper_fgath (H5F_t *f, const struct H5O_layout_t *layout,
 			       const struct H5O_efl_t *efl, size_t elmt_size,
 			       const H5S_t *file_space,
 			       H5S_sel_iter_t *file_iter, size_t nelmts,
-			       const H5D_transfer_t xfer_mode,
+			       const void *_xfer_parms,
 			       void *buf/*out*/);
 static herr_t H5S_hyper_fscat (H5F_t *f, const struct H5O_layout_t *layout,
 			       const struct H5O_pline_t *pline,
 			       const struct H5O_efl_t *efl, size_t elmt_size,
 			       const H5S_t *file_space,
 			       H5S_sel_iter_t *file_iter, size_t nelmts,
-			       const H5D_transfer_t xfer_mode,
+			       const void *_xfer_parms,
 			       const void *buf);
 static size_t H5S_hyper_mgath (const void *_buf, size_t elmt_size,
 			       const H5S_t *mem_space,
@@ -91,6 +93,9 @@ const H5S_mconv_t	H5S_HYPER_MCONV[1] = {{
     H5S_hyper_mscat,				/*scatter		*/
 }};
 
+/* Array for use with I/O algorithms which frequently need array of zeros */
+static const hssize_t	zero[H5O_LAYOUT_NDIMS]={0};		/* Array of zeros */
+
 
 /*-------------------------------------------------------------------------
  * Function:	H5S_hyper_init
@@ -178,14 +183,12 @@ H5S_hyper_favail (const H5S_t __unused__ *space,
 int
 H5S_hyper_compare_regions (const void *r1, const void *r2)
 {
-    if (((const H5S_hyper_region_t *)r1)->start <
-	((const H5S_hyper_region_t *)r2)->start)
+    if (((const H5S_hyper_region_t *)r1)->start < ((const H5S_hyper_region_t *)r2)->start)
         return(-1);
-    else if (((const H5S_hyper_region_t *)r1)->start >
-	     ((const H5S_hyper_region_t *)r2)->start)
-	return(1);
+    else if (((const H5S_hyper_region_t *)r1)->start > ((const H5S_hyper_region_t *)r2)->start)
+        return(1);
     else
-	return(0);
+        return(0);
 }   /* end H5S_hyper_compare_regions */
 
 /*-------------------------------------------------------------------------
@@ -205,12 +208,13 @@ H5S_hyper_compare_regions (const void *r1, const void *r2)
  *
  *-------------------------------------------------------------------------
  */
-static H5S_hyper_region_t *
+static hid_t
 H5S_hyper_get_regions (size_t *num_regions, intn dim, size_t bound_count,
    H5S_hyper_bound_t **lo_bounds, H5S_hyper_bound_t **hi_bounds, hssize_t *pos,
    hssize_t *offset)
 {
-    H5S_hyper_region_t *ret_value=NULL;	/* Pointer to array to return */
+    hid_t ret_value=FAIL;	            /* Id of temporary buffer to return */
+    H5S_hyper_region_t *reg=NULL;	    /* Pointer to array of regions */
     H5S_hyper_node_t *node;             /* Region node for a given boundary */
     size_t num_reg=0;                   /* Number of regions in array */
     size_t curr_reg=0;                  /* The current region we are working with */
@@ -219,7 +223,7 @@ H5S_hyper_get_regions (size_t *num_regions, intn dim, size_t bound_count,
     intn temp_dim;                      /* Temporary dim. holder */
     size_t i;                           /* Counters */
 
-    FUNC_ENTER (H5S_hyper_get_regions, NULL);
+    FUNC_ENTER (H5S_hyper_get_regions, FAIL);
     
     assert(num_regions);
     assert(lo_bounds);
@@ -242,12 +246,13 @@ H5S_hyper_get_regions (size_t *num_regions, intn dim, size_t bound_count,
             if(pos[0]==(-1) || ((pos[0]+offset[0])>=lo_bounds[0][i].bound && (pos[0]+offset[0]) <= hi_bounds[0][i].bound)) {
                 /* Check if we've allocated the array yet */
                 if(num_reg==0) {
-                    /* Allocate array */
-                    ret_value=H5MM_malloc(sizeof(H5S_hyper_region_t));
+                    /* Allocate temporary buffer */
+                    ret_value=H5TB_get_buf(sizeof(H5S_hyper_region_t),0,(void **)&reg);
 
                     /* Initialize with first region */
-                    ret_value[0].start=MAX(lo_bounds[0][i].bound,pos[0])+offset[0];
-                    ret_value[0].end=hi_bounds[0][i].bound+offset[0];
+                    reg[0].start=MAX(lo_bounds[0][i].bound,pos[0])+offset[0];
+                    reg[0].end=hi_bounds[0][i].bound+offset[0];
+                    reg[0].node=hi_bounds[0][i].node;
 
                     /* Increment the number of regions */
                     num_reg++;
@@ -256,20 +261,22 @@ H5S_hyper_get_regions (size_t *num_regions, intn dim, size_t bound_count,
                      * Check if we should merge this region into the current
                      * region.
                      */
-                    if(lo_bounds[0][i].bound<ret_value[curr_reg].end) {
-                        ret_value[curr_reg].end=MAX(hi_bounds[0][i].bound,
-						    ret_value[curr_reg].end)+(offset!=NULL ? offset[0] : 0 );
+                    if(lo_bounds[0][i].bound<reg[curr_reg].end) {
+                        reg[curr_reg].end=MAX(hi_bounds[0][i].bound,
+						    reg[curr_reg].end)+(offset!=NULL ? offset[0] : 0 );
                     } else { /* no overlap with previous region, add new region */
                         /* Check if this is actually a different region */
-                        if(lo_bounds[0][i].bound!=ret_value[curr_reg].start &&
-                            hi_bounds[0][i].bound!=ret_value[curr_reg].end) {
+                        if(lo_bounds[0][i].bound!=reg[curr_reg].start &&
+                            hi_bounds[0][i].bound!=reg[curr_reg].end) {
 
                             /* Enlarge array */
-                            ret_value=H5MM_realloc(ret_value,(sizeof(H5S_hyper_region_t)*(num_reg+1)));
+                            H5TB_resize_buf(ret_value,(sizeof(H5S_hyper_region_t)*(num_reg+1)));
+                            reg=H5TB_buf_ptr(ret_value);
 
                             /* Initialize with new region */
-                            ret_value[num_reg].start=lo_bounds[0][i].bound+offset[0];
-                            ret_value[num_reg].end=hi_bounds[0][i].bound+offset[0];
+                            reg[num_reg].start=lo_bounds[0][i].bound+offset[0];
+                            reg[num_reg].end=hi_bounds[0][i].bound+offset[0];
+                            reg[num_reg].node=hi_bounds[0][i].node;
 
                             /*
                              * Increment the number of regions & the current
@@ -329,19 +336,20 @@ H5S_hyper_get_regions (size_t *num_regions, intn dim, size_t bound_count,
 #ifdef QAK
 		    printf("%s: check 3.1\n", FUNC);
 #endif /* QAK */
-                    /* Allocate array */
-                    ret_value=H5MM_malloc(sizeof(H5S_hyper_region_t));
+                    /* Allocate temporary buffer */
+                    ret_value=H5TB_get_buf(sizeof(H5S_hyper_region_t),0,(void **)&reg);
 
                     /* Initialize with first region */
-                    ret_value[0].start=MAX(node->start[next_dim],pos[next_dim])+offset[next_dim];
-                    ret_value[0].end=node->end[next_dim]+offset[next_dim];
+                    reg[0].start=MAX(node->start[next_dim],pos[next_dim])+offset[next_dim];
+                    reg[0].end=node->end[next_dim]+offset[next_dim];
+                    reg[0].node=node;
 #ifdef QAK
 		    printf("%s: check 3.2, lo_bounds=%d, start=%d, "
 			   "hi_bounds=%d, end=%d\n",
 			   FUNC, (int)node->start[next_dim],
-			   (int)ret_value[curr_reg].start,
+			   (int)reg[curr_reg].start,
 			   (int)node->end[next_dim],
-			   (int)ret_value[curr_reg].end);
+			   (int)reg[curr_reg].end);
 #endif /* QAK */
 
                     /* Increment the number of regions */
@@ -351,18 +359,18 @@ H5S_hyper_get_regions (size_t *num_regions, intn dim, size_t bound_count,
 		    printf("%s: check 4.0, lo_bounds=%d, start=%d, "
 			   "hi_bounds=%d, end=%d\n",
 			   FUNC, (int)node->start[next_dim],
-			   (int)ret_value[curr_reg].start,
+			   (int)reg[curr_reg].start,
 			   (int)node->end[next_dim],
-			   (int)ret_value[curr_reg].end);
+			   (int)reg[curr_reg].end);
 #endif /* QAK */
                     /* Enlarge array */
-                    ret_value=H5MM_realloc(ret_value,
-					   (sizeof(H5S_hyper_region_t)*
-					    (num_reg+1)));
+                    H5TB_resize_buf(ret_value,(sizeof(H5S_hyper_region_t)*(num_reg+1)));
+                    reg=H5TB_buf_ptr(ret_value);
 
                     /* Initialize with new region */
-                    ret_value[num_reg].start=node->start[next_dim]+offset[next_dim];
-                    ret_value[num_reg].end=node->end[next_dim]+offset[next_dim];
+                    reg[num_reg].start=node->start[next_dim]+offset[next_dim];
+                    reg[num_reg].end=node->end[next_dim]+offset[next_dim];
+                    reg[num_reg].node=node;
 
                     /* Increment the number of regions & the current region */
                     num_reg++;
@@ -373,15 +381,15 @@ H5S_hyper_get_regions (size_t *num_regions, intn dim, size_t bound_count,
 
         /* Sort region list and eliminate duplicates if necessary */
         if(num_reg>1) {
-            HDqsort(ret_value,num_reg,sizeof(H5S_hyper_region_t),
-		    H5S_hyper_compare_regions);
+            HDqsort(reg,num_reg,sizeof(H5S_hyper_region_t),H5S_hyper_compare_regions);
             for(i=1,curr_reg=0,uniq_reg=1; i<num_reg; i++) {
-                if(ret_value[curr_reg].start!=ret_value[i].start &&
-                        ret_value[curr_reg].end!=ret_value[i].end) {
+                if(reg[curr_reg].start!=reg[i].start &&
+                        reg[curr_reg].end!=reg[i].end) {
                     uniq_reg++;
                     curr_reg++;
-                    ret_value[curr_reg].start=ret_value[i].start;
-                    ret_value[curr_reg].end=ret_value[i].end;
+                    reg[curr_reg].start=reg[i].start;
+                    reg[curr_reg].end=reg[i].end;
+                    reg[curr_reg].node=reg[i].node;
                 } /* end if */
             } /* end for */
             num_reg=uniq_reg;
@@ -392,17 +400,194 @@ H5S_hyper_get_regions (size_t *num_regions, intn dim, size_t bound_count,
     *num_regions=num_reg;
 
 #ifdef QAK
-    printf("%s: check 10.0, ret_value=%p, num_reg=%d\n",
-	   FUNC,ret_value,num_reg);
+    printf("%s: check 10.0, reg=%p, num_reg=%d\n",
+	   FUNC,reg,num_reg);
     for(i=0; i<num_reg; i++)
         printf("%s: start[%d]=%d, end[%d]=%d\n",
-	       FUNC,i,(int)ret_value[i].start,i,(int)ret_value[i].end);
+	       FUNC,i,(int)reg[i].start,i,(int)reg[i].end);
 #endif /* QAK */
 
     FUNC_LEAVE (ret_value);
 } /* end H5S_hyper_get_regions() */
 
 /*-------------------------------------------------------------------------
+ * Function:	H5S_hyper_block_cache
+ *
+ * Purpose:	Cache a hyperslab block for reading or writing.
+ *
+ * Return:	Success:	SUCCEED
+ *
+ *		Failure:	FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, September 21, 1998
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5S_hyper_block_cache (H5S_hyper_node_t *node, H5S_hyper_fhyper_info_t *fhyper_info, uintn block_read)
+{
+    hssize_t	file_offset[H5O_LAYOUT_NDIMS];	/*offset of slab in file*/
+    hsize_t	hsize[H5O_LAYOUT_NDIMS];	/*size of hyperslab	*/
+    intn i;                   /* Counters */
+
+    FUNC_ENTER (H5S_hyper_block_cache, SUCCEED);
+
+    assert(node);
+    assert(fhyper_info);
+
+    /* Allocate temporary buffer of proper size */
+    if((node->cinfo.block_id=H5TB_get_buf(node->cinfo.size*fhyper_info->elmt_size,1,(void **)&(node->cinfo.block)))==FAIL)
+        HRETURN_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL,
+            "can't allocate hyperslab cache block");
+
+    /* Read in block, if we are read caching */
+    if(block_read) {
+        /* Copy the location of the region in the file */
+        HDmemcpy(file_offset,node->start,(fhyper_info->space->extent.u.simple.rank * sizeof(hssize_t)));
+        file_offset[fhyper_info->space->extent.u.simple.rank]=0;
+
+        /* Set the hyperslab size to read */
+        for(i=0; i<fhyper_info->space->extent.u.simple.rank; i++)
+            hsize[i]=(node->end[i]-node->start[i])+1;
+        hsize[fhyper_info->space->extent.u.simple.rank]=fhyper_info->elmt_size;
+
+        if (H5F_arr_read (fhyper_info->f, fhyper_info->layout,
+                fhyper_info->pline, fhyper_info->efl,
+                hsize, hsize, zero, file_offset,
+                fhyper_info->xfer_parms->xfer_mode, node->cinfo.block/*out*/)<0)
+            HRETURN_ERROR (H5E_DATASPACE, H5E_READERROR, FAIL, "read error");
+    } /* end if */
+    else {
+/* keep information for writing block later? */
+    } /* end else */
+    
+    /* Set up parameters for accessing block */
+    node->cinfo.left=node->cinfo.size;
+    node->cinfo.pos=node->cinfo.block;
+
+    /* Set cached flag */
+    node->cinfo.cached=1;
+
+    FUNC_LEAVE (SUCCEED);
+}   /* H5S_hyper_block_cache() */
+
+/*-------------------------------------------------------------------------
+ * Function:	H5S_hyper_block_read
+ *
+ * Purpose:	Read in data from a cached hyperslab block
+ *
+ * Return:	Success:	SUCCEED
+ *
+ *		Failure:	FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, September 21, 1998
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5S_hyper_block_read (H5S_hyper_node_t *node, H5S_hyper_fhyper_info_t *fhyper_info, hsize_t region_size)
+{
+    FUNC_ENTER (H5S_hyper_block_read, SUCCEED);
+
+    assert(node && node->cinfo.cached);
+    assert(fhyper_info);
+
+    /* Copy the elements into the user's buffer */
+    /*
+        !! NOTE !! This will need to be changed for different dimension
+            permutations from the standard 'C' ordering!
+    */
+    HDmemcpy(fhyper_info->dst,node->cinfo.pos,region_size*fhyper_info->elmt_size);
+
+    /* Decrement the number of elements left in block to read & move the offset */
+    node->cinfo.pos+=region_size*fhyper_info->elmt_size;
+    node->cinfo.left-=region_size;
+
+    /* If we've read in all the elements from the block, throw it away */
+    if(node->cinfo.left==0) {
+        /* Release the temporary buffer */
+        H5TB_release_buf(node->cinfo.block_id);
+
+        /* Reset the caching flag for next time */
+        node->cinfo.cached=0;
+    } /* end if */
+
+    FUNC_LEAVE (SUCCEED);
+}   /* H5S_hyper_block_read() */
+
+/*-------------------------------------------------------------------------
+ * Function:	H5S_hyper_block_write
+ *
+ * Purpose:	Write out data to a cached hyperslab block
+ *
+ * Return:	Success:	SUCCEED
+ *
+ *		Failure:	FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, September 21, 1998
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5S_hyper_block_write (H5S_hyper_node_t *node, H5S_hyper_fhyper_info_t *fhyper_info, hsize_t region_size)
+{
+    hssize_t	file_offset[H5O_LAYOUT_NDIMS];	/*offset of slab in file*/
+    hsize_t	hsize[H5O_LAYOUT_NDIMS];	/*size of hyperslab	*/
+    intn i;                   /* Counters */
+
+    FUNC_ENTER (H5S_hyper_block_write, SUCCEED);
+
+    assert(node && node->cinfo.cached);
+    assert(fhyper_info);
+
+    /* Copy the elements into the user's buffer */
+    /*
+        !! NOTE !! This will need to be changed for different dimension
+            permutations from the standard 'C' ordering!
+    */
+    HDmemcpy(node->cinfo.pos,fhyper_info->src,region_size*fhyper_info->elmt_size);
+
+    /* Decrement the number of elements left in block to read & move the offset */
+    node->cinfo.pos+=region_size*fhyper_info->elmt_size;
+    node->cinfo.left-=region_size;
+
+    /* If we've read in all the elements from the block, throw it away */
+    if(node->cinfo.left==0) {
+        /* Copy the location of the region in the file */
+        HDmemcpy(file_offset,node->start,(fhyper_info->space->extent.u.simple.rank * sizeof(hssize_t)));
+        file_offset[fhyper_info->space->extent.u.simple.rank]=0;
+
+        /* Set the hyperslab size to write */
+        for(i=0; i<fhyper_info->space->extent.u.simple.rank; i++)
+            hsize[i]=(node->end[i]-node->start[i])+1;
+        hsize[fhyper_info->space->extent.u.simple.rank]=fhyper_info->elmt_size;
+
+        if (H5F_arr_write (fhyper_info->f, fhyper_info->layout,
+                fhyper_info->pline, fhyper_info->efl,
+                hsize, hsize, zero, file_offset,
+                fhyper_info->xfer_parms->xfer_mode, node->cinfo.block/*out*/)<0)
+            HRETURN_ERROR (H5E_DATASPACE, H5E_WRITEERROR, FAIL, "write error");
+
+        /* Release the temporary buffer */
+        H5TB_release_buf(node->cinfo.block_id);
+
+        /* Reset the caching flag for next time */
+        node->cinfo.cached=0;
+    } /* end if */
+
+    FUNC_LEAVE (SUCCEED);
+}   /* H5S_hyper_block_write() */
+
+/*-------------------------------------------------------------------------
  * Function:	H5S_hyper_fread
  *
  * Purpose:	Recursively gathers data points from a file using the
@@ -425,7 +610,8 @@ H5S_hyper_fread (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
     hssize_t	file_offset[H5O_LAYOUT_NDIMS];	/*offset of slab in file*/
     hsize_t	hsize[H5O_LAYOUT_NDIMS];	/*size of hyperslab	*/
     hsize_t region_size;                /* Size of lowest region */
-    hssize_t	zero[H5O_LAYOUT_NDIMS];		/*zero			*/
+    uintn parm_init=0;          /* Whether one-shot parameters set up */
+    hid_t reg_id;               /* ID of temporary region buffer */
     H5S_hyper_region_t *regions;  /* Pointer to array of hyperslab nodes overlapped */
     size_t num_regions;         /* number of regions overlapped */
     size_t i;                   /* Counters */
@@ -442,10 +628,13 @@ H5S_hyper_fread (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
 
     /* Get a sorted list (in the next dimension down) of the regions which */
     /*  overlap the current index in this dim */
-    if((regions=H5S_hyper_get_regions(&num_regions,dim,
+    if((reg_id=H5S_hyper_get_regions(&num_regions,dim,
             fhyper_info->space->select.sel_info.hyper.hyper_lst->count,
             fhyper_info->lo_bounds, fhyper_info->hi_bounds,
-            fhyper_info->iter->hyp.pos,fhyper_info->space->select.offset))!=NULL) {
+            fhyper_info->iter->hyp.pos,fhyper_info->space->select.offset))!=FAIL) {
+
+        /* Get the pointer to the actual regions array */
+        regions=H5TB_buf_ptr(reg_id);
 
         /*
 	 * Check if this is the second to last dimension in dataset (Which
@@ -461,50 +650,63 @@ H5S_hyper_fread (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
 #endif /* QAK */
         if((dim+2)==fhyper_info->space->extent.u.simple.rank) {
 
-            /* Set up hyperslab I/O parameters which apply to all regions */
-
-            /* Copy the location of the region in the file */
-            HDmemcpy(file_offset, fhyper_info->iter->hyp.pos,
-		     (fhyper_info->space->extent.u.simple.rank *
-		      sizeof(hssize_t)));
-            file_offset[fhyper_info->space->extent.u.simple.rank]=0;
+            /* perform I/O on data from regions */
+            for(i=0; i<num_regions && fhyper_info->nelmts>0; i++) {
+                /* Compute the size of the region to read */
+                region_size=MIN(fhyper_info->nelmts, (regions[i].end-regions[i].start)+1);
 
-            /* Set the hyperslab size to copy */
-            hsize[0]=1;
-            H5V_array_fill(hsize, hsize, sizeof(hsize[0]),
-			   fhyper_info->space->extent.u.simple.rank);
-            hsize[fhyper_info->space->extent.u.simple.rank]=fhyper_info->elmt_size;
+                /* Check if this hyperslab block is cached or could be cached */
+                if(!regions[i].node->cinfo.cached && (fhyper_info->xfer_parms->cache_hyper && (fhyper_info->xfer_parms->block_limit==0 || fhyper_info->xfer_parms->block_limit>=(regions[i].node->cinfo.size*fhyper_info->elmt_size)))) {
+                    /* if we aren't cached, attempt to cache the block */
+                    H5S_hyper_block_cache(regions[i].node,fhyper_info,1);
+                } /* end if */
 
-            /* Set the memory offset to the origin */
-            HDmemset (zero, 0, fhyper_info->layout->ndims*sizeof(*zero));
+                /* Read information from the cached block */
+                if(regions[i].node->cinfo.cached) {
+                    if(H5S_hyper_block_read(regions[i].node,fhyper_info,region_size)==FAIL)
+                        HRETURN_ERROR (H5E_DATASPACE, H5E_READERROR, 0, "read error");
+                }
+                else {
+                    /* Set up hyperslab I/O parameters which apply to all regions */
+                    if(!parm_init) {
+                        /* Copy the location of the region in the file */
+                        HDmemcpy(file_offset,fhyper_info->iter->hyp.pos,(fhyper_info->space->extent.u.simple.rank * sizeof(hssize_t)));
+                        file_offset[fhyper_info->space->extent.u.simple.rank]=0;
+
+                        /* Set the hyperslab size to copy */
+                        hsize[0]=1;
+                        H5V_array_fill(hsize,hsize,sizeof(hsize[0]),fhyper_info->space->extent.u.simple.rank);
+                        hsize[fhyper_info->space->extent.u.simple.rank]=fhyper_info->elmt_size;
+                        
+                        /* Set flag */
+                        parm_init=1;
+                    } /* end if */
 
-            /* perform I/O on data from regions */
-            for(i=0; i<num_regions && fhyper_info->nelmts>0; i++) {
 #ifdef QAK
-		printf("%s: check 2.2, i=%d\n",FUNC,(int)i);
+            printf("%s: check 2.2, i=%d\n",FUNC,(int)i);
 #endif /* QAK */
-                region_size=MIN(fhyper_info->nelmts,
-				(regions[i].end-regions[i].start)+1);
-                hsize[fhyper_info->space->extent.u.simple.rank-1]=region_size;
-                file_offset[fhyper_info->space->extent.u.simple.rank-1]=regions[i].start;
+                    /* Fill in the region specific parts of the I/O request */
+                    hsize[fhyper_info->space->extent.u.simple.rank-1]=region_size;
+                    file_offset[fhyper_info->space->extent.u.simple.rank-1]=regions[i].start;
 
-                /*
-                 * Gather from file.
-                 */
-                if (H5F_arr_read (fhyper_info->f, fhyper_info->layout,
-				  fhyper_info->pline, fhyper_info->efl,
-				  hsize, hsize, zero, file_offset,
-				  fhyper_info->xfer_mode,
-				  fhyper_info->dst/*out*/)<0) {
-                    HRETURN_ERROR (H5E_DATASPACE, H5E_READERROR, 0,
-				   "read error");
-                }
+                    /*
+                     * Gather from file.
+                     */
+                    if (H5F_arr_read (fhyper_info->f, fhyper_info->layout,
+                      fhyper_info->pline, fhyper_info->efl,
+                      hsize, hsize, zero, file_offset,
+                      fhyper_info->xfer_parms->xfer_mode,
+                      fhyper_info->dst/*out*/)<0) {
+                        HRETURN_ERROR (H5E_DATASPACE, H5E_READERROR, 0,
+                       "read error");
+                    }
 #ifdef QAK
-		printf("%s: check 2.3, region #%d\n",FUNC,(int)i);
-		for(j=0; j<fhyper_info->space->extent.u.simple.rank; j++)
-		    printf("%s: %d - pos=%d\n",
-			   FUNC,j,(int)fhyper_info->iter->hyp.pos[j]);
+            printf("%s: check 2.3, region #%d\n",FUNC,(int)i);
+            for(j=0; j<fhyper_info->space->extent.u.simple.rank; j++)
+                printf("%s: %d - pos=%d\n",
+                   FUNC,j,(int)fhyper_info->iter->hyp.pos[j]);
 #endif /* QAK */
+                } /* end else */
 
                 /* Advance the pointer in the buffer */
                 fhyper_info->dst = ((uint8 *)fhyper_info->dst) +
@@ -520,8 +722,7 @@ H5S_hyper_fread (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
                 if(region_size==(hsize_t)((regions[i].end-regions[i].start)+1))
                     fhyper_info->iter->hyp.pos[dim+1]=(-1);
                 else
-                    fhyper_info->iter->hyp.pos[dim+1] = regions[i].start +
-							region_size;
+                    fhyper_info->iter->hyp.pos[dim+1] = regions[i].start + region_size;
 
                 /* Decrement the iterator count */
                 fhyper_info->iter->hyp.elmt_left-=region_size;
@@ -537,9 +738,7 @@ H5S_hyper_fread (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
             /* Step through each region in this dimension */
             for(i=0; i<num_regions && fhyper_info->nelmts>0; i++) {
                 /* Step through each location in each region */
-                for(j=regions[i].start;
-		    j<=regions[i].end && fhyper_info->nelmts>0;
-		    j++) {
+                for(j=regions[i].start; j<=regions[i].end && fhyper_info->nelmts>0; j++) {
 #ifdef QAK
 		    printf("%s: check 4.0, dim=%d, location=%d\n",FUNC,dim,j);
 #endif /* QAK */
@@ -560,8 +759,8 @@ H5S_hyper_fread (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
             } /* end for */
         } /* end else */
 
-        /* Free the region space */
-        H5MM_xfree(regions);
+        /* Release the temporary buffer */
+        H5TB_release_buf(reg_id);
     } /* end if */
 
     FUNC_LEAVE (num_read);
@@ -595,9 +794,10 @@ H5S_hyper_fgath (H5F_t *f, const struct H5O_layout_t *layout,
 		 const struct H5O_pline_t *pline,
 		 const struct H5O_efl_t *efl, size_t elmt_size,
 		 const H5S_t *file_space, H5S_sel_iter_t *file_iter,
-		 size_t nelmts, const H5D_transfer_t xfer_mode,
+		 size_t nelmts, const void *_xfer_parms,
 		 void *_buf/*out*/)
 {
+    const H5D_xfer_t *xfer_parms=(const H5D_xfer_t *)_xfer_parms;   /* Coerce the type */
     H5S_hyper_bound_t **lo_bounds;    /* Lower (closest to the origin) bound array for each dimension */
     H5S_hyper_bound_t **hi_bounds;    /* Upper (farthest from the origin) bound array for each dimension */
     H5S_hyper_fhyper_info_t fhyper_info;  /* Block of parameters to pass into recursive calls */
@@ -642,7 +842,7 @@ H5S_hyper_fgath (H5F_t *f, const struct H5O_layout_t *layout,
     fhyper_info.space=file_space;
     fhyper_info.iter=file_iter;
     fhyper_info.nelmts=nelmts;
-    fhyper_info.xfer_mode=xfer_mode;
+    fhyper_info.xfer_parms=xfer_parms;
     fhyper_info.src=NULL;
     fhyper_info.dst=_buf;
     fhyper_info.lo_bounds=lo_bounds;
@@ -688,7 +888,8 @@ H5S_hyper_fwrite (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
     hssize_t	file_offset[H5O_LAYOUT_NDIMS];	/*offset of slab in file*/
     hsize_t	hsize[H5O_LAYOUT_NDIMS];	/*size of hyperslab	*/
     hsize_t region_size;                /* Size of lowest region */
-    hssize_t	zero[H5O_LAYOUT_NDIMS];		/*zero			*/
+    uintn parm_init=0;          /* Whether one-shot parameters set up */
+    hid_t reg_id;               /* ID of temporary region buffer */
     H5S_hyper_region_t *regions;  /* Pointer to array of hyperslab nodes overlapped */
     size_t num_regions;         /* number of regions overlapped */
     size_t i;                   /* Counters */
@@ -699,52 +900,77 @@ H5S_hyper_fwrite (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
 
     assert(fhyper_info);
 
+#ifdef QAK
+    printf("%s: check 1.0\n", FUNC);
+#endif /* QAK */
     /* Get a sorted list (in the next dimension down) of the regions which */
     /*  overlap the current index in this dim */
-    if((regions=H5S_hyper_get_regions(&num_regions,dim,
+    if((reg_id=H5S_hyper_get_regions(&num_regions,dim,
             fhyper_info->space->select.sel_info.hyper.hyper_lst->count,
             fhyper_info->lo_bounds, fhyper_info->hi_bounds,
-            fhyper_info->iter->hyp.pos,fhyper_info->space->select.offset))!=NULL) {
+            fhyper_info->iter->hyp.pos,fhyper_info->space->select.offset))!=FAIL) {
+
+        /* Get the pointer to the actual regions array */
+        regions=H5TB_buf_ptr(reg_id);
+#ifdef QAK
+    printf("%s: check 1.1, regions=%p\n", FUNC,regions);
+#endif /* QAK */
 
         /* Check if this is the second to last dimension in dataset */
         /*  (Which means that we've got a list of the regions in the fastest */
         /*   changing dimension and should input those regions) */
         if((dim+2)==fhyper_info->space->extent.u.simple.rank) {
 
-            /* Set up hyperslab I/O parameters which apply to all regions */
+            /* perform I/O on data from regions */
+            for(i=0; i<num_regions && fhyper_info->nelmts>0; i++) {
+                /* Compute the size of the region to read */
+                region_size=MIN(fhyper_info->nelmts, (regions[i].end-regions[i].start)+1);
 
-            /* Copy the location of the region in the file */
-            HDmemcpy(file_offset, fhyper_info->iter->hyp.pos,
-		     (fhyper_info->space->extent.u.simple.rank *
-		      sizeof(hssize_t)));
-            file_offset[fhyper_info->space->extent.u.simple.rank]=0;
+                /* Check if this hyperslab block is cached or could be cached */
+                if(!regions[i].node->cinfo.cached && (fhyper_info->xfer_parms->cache_hyper && (fhyper_info->xfer_parms->block_limit==0 || fhyper_info->xfer_parms->block_limit>=(regions[i].node->cinfo.size*fhyper_info->elmt_size)))) {
+                    /* if we aren't cached, attempt to cache the block */
+                    H5S_hyper_block_cache(regions[i].node,fhyper_info,0);
+                } /* end if */
 
-            /* Set the hyperslab size to copy */
-            hsize[0]=1;
-            H5V_array_fill(hsize, hsize, sizeof(hsize[0]),
-			   fhyper_info->space->extent.u.simple.rank);
-            hsize[fhyper_info->space->extent.u.simple.rank]=fhyper_info->elmt_size;
+                /* Read information from the cached block */
+                if(regions[i].node->cinfo.cached) {
+                    if(H5S_hyper_block_write(regions[i].node,fhyper_info,region_size)==FAIL)
+                        HRETURN_ERROR (H5E_DATASPACE, H5E_WRITEERROR, 0, "write error");
+                }
+                else {
+                    /* Set up hyperslab I/O parameters which apply to all regions */
+                    if(!parm_init) {
 
-            /* Set the memory offset to the origin */
-            HDmemset (zero, 0, fhyper_info->layout->ndims*sizeof(*zero));
+                        /* Copy the location of the region in the file */
+                        HDmemcpy(file_offset, fhyper_info->iter->hyp.pos,
+                         (fhyper_info->space->extent.u.simple.rank *
+                          sizeof(hssize_t)));
+                        file_offset[fhyper_info->space->extent.u.simple.rank]=0;
 
-            /* perform I/O on data from regions */
-            for(i=0; i<num_regions && fhyper_info->nelmts>0; i++) {
-                region_size=MIN(fhyper_info->nelmts,
-				(regions[i].end-regions[i].start)+1);
-                hsize[fhyper_info->space->extent.u.simple.rank-1]=region_size;
-                file_offset[fhyper_info->space->extent.u.simple.rank-1]=regions[i].start;
+                        /* Set the hyperslab size to copy */
+                        hsize[0]=1;
+                        H5V_array_fill(hsize, hsize, sizeof(hsize[0]),
+                           fhyper_info->space->extent.u.simple.rank);
+                        hsize[fhyper_info->space->extent.u.simple.rank]=fhyper_info->elmt_size;
 
-                /*
-                 * Scatter from file.
-                 */
-                if (H5F_arr_write (fhyper_info->f, fhyper_info->layout,
-				   fhyper_info->pline, fhyper_info->efl,
-				   hsize, hsize, zero, file_offset,
-				   fhyper_info->xfer_mode,
-				   fhyper_info->src)<0) {
-                    HRETURN_ERROR (H5E_DATASPACE, H5E_WRITEERROR, 0, "write error");
-                }
+                        /* Set flag */
+                        parm_init=1;
+                    } /* end if */
+
+                    hsize[fhyper_info->space->extent.u.simple.rank-1]=region_size;
+                    file_offset[fhyper_info->space->extent.u.simple.rank-1]=regions[i].start;
+
+                    /*
+                     * Scatter to file.
+                     */
+                    if (H5F_arr_write (fhyper_info->f, fhyper_info->layout,
+                       fhyper_info->pline, fhyper_info->efl,
+                       hsize, hsize, zero, file_offset,
+                       fhyper_info->xfer_parms->xfer_mode,
+                       fhyper_info->src)<0) {
+                        HRETURN_ERROR (H5E_DATASPACE, H5E_WRITEERROR, 0, "write error");
+                    }
+                } /* end else */
 
                 /* Advance the pointer in the buffer */
                 fhyper_info->src = ((const uint8 *)fhyper_info->src) +
@@ -794,10 +1020,13 @@ H5S_hyper_fwrite (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
             } /* end for */
         } /* end else */
 
-        /* Free the region space */
-        H5MM_xfree(regions);
+        /* Release the temporary buffer */
+        H5TB_release_buf(reg_id);
     } /* end if */
 
+#ifdef QAK
+    printf("%s: check 2.0\n", FUNC);
+#endif /* QAK */
     FUNC_LEAVE (num_written);
 }   /* H5S_hyper_fwrite() */
 
@@ -826,9 +1055,10 @@ H5S_hyper_fscat (H5F_t *f, const struct H5O_layout_t *layout,
 		 const struct H5O_pline_t *pline,
 		 const struct H5O_efl_t *efl, size_t elmt_size,
 		 const H5S_t *file_space, H5S_sel_iter_t *file_iter,
-		 size_t nelmts, const H5D_transfer_t xfer_mode,
+		 size_t nelmts, const void *_xfer_parms,
 		 const void *_buf)
 {
+    const H5D_xfer_t *xfer_parms=(const H5D_xfer_t *)_xfer_parms;   /* Coerce the type */
     H5S_hyper_bound_t **lo_bounds;    /* Lower (closest to the origin) bound array for each dimension */
     H5S_hyper_bound_t **hi_bounds;    /* Upper (farthest from the origin) bound array for each dimension */
     H5S_hyper_fhyper_info_t fhyper_info;  /* Block of parameters to pass into recursive calls */
@@ -874,7 +1104,7 @@ H5S_hyper_fscat (H5F_t *f, const struct H5O_layout_t *layout,
     fhyper_info.space=file_space;
     fhyper_info.iter=file_iter;
     fhyper_info.nelmts=nelmts;
-    fhyper_info.xfer_mode=xfer_mode;
+    fhyper_info.xfer_parms=xfer_parms;
     fhyper_info.src=_buf;
     fhyper_info.dst=NULL;
     fhyper_info.lo_bounds=lo_bounds;
@@ -888,6 +1118,9 @@ H5S_hyper_fscat (H5F_t *f, const struct H5O_layout_t *layout,
     H5MM_xfree(lo_bounds);
     H5MM_xfree(hi_bounds);
     
+#ifdef QAK
+    printf("%s: check 2.0\n", FUNC);
+#endif /* QAK */
     FUNC_LEAVE (num_written);
 } /* H5S_hyper_fscat() */
 
@@ -915,7 +1148,7 @@ H5S_hyper_mread (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
     hssize_t	mem_offset[H5O_LAYOUT_NDIMS];	/*offset of slab in memory*/
     hsize_t	hsize[H5O_LAYOUT_NDIMS];	/*size of hyperslab	*/
     hsize_t region_size;                /* Size of lowest region */
-    hssize_t	zero[H5O_LAYOUT_NDIMS];		/*zero			*/
+    hid_t reg_id;               /* ID of temporary region buffer */
     H5S_hyper_region_t *regions;  /* Pointer to array of hyperslab nodes overlapped */
     size_t num_regions;         /* number of regions overlapped */
     size_t i;                   /* Counters */
@@ -932,10 +1165,13 @@ H5S_hyper_mread (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
 
     /* Get a sorted list (in the next dimension down) of the regions which */
     /*  overlap the current index in this dim */
-    if((regions=H5S_hyper_get_regions(&num_regions,dim,
+    if((reg_id=H5S_hyper_get_regions(&num_regions,dim,
             fhyper_info->space->select.sel_info.hyper.hyper_lst->count,
             fhyper_info->lo_bounds, fhyper_info->hi_bounds,
-            fhyper_info->iter->hyp.pos,fhyper_info->space->select.offset))!=NULL) {
+            fhyper_info->iter->hyp.pos,fhyper_info->space->select.offset))!=FAIL) {
+
+        /* Get the pointer to the actual regions array */
+        regions=H5TB_buf_ptr(reg_id);
 
         /* Check if this is the second to last dimension in dataset */
         /*  (Which means that we've got a list of the regions in the fastest */
@@ -970,10 +1206,6 @@ H5S_hyper_mread (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
 			   fhyper_info->space->extent.u.simple.rank);
             hsize[fhyper_info->space->extent.u.simple.rank]=fhyper_info->elmt_size;
 
-            /* Set the memory offset to the origin */
-            HDmemset (zero, 0, ((fhyper_info->space->extent.u.simple.rank+1)*
-				sizeof(*zero)));
-
             /* perform I/O on data from regions */
             for(i=0; i<num_regions && fhyper_info->nelmts>0; i++) {
                 region_size=MIN(fhyper_info->nelmts,
@@ -1049,8 +1281,8 @@ H5S_hyper_mread (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
             } /* end for */
         } /* end else */
 
-        /* Free the region space */
-        H5MM_xfree(regions);
+        /* Release the temporary buffer */
+        H5TB_release_buf(reg_id);
     } /* end if */
 
     FUNC_LEAVE (num_read);
@@ -1190,7 +1422,7 @@ H5S_hyper_mwrite (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
     hssize_t	mem_offset[H5O_LAYOUT_NDIMS];	/*offset of slab in file*/
     hsize_t	hsize[H5O_LAYOUT_NDIMS];	/*size of hyperslab	*/
     hsize_t region_size;                /* Size of lowest region */
-    hssize_t	zero[H5O_LAYOUT_NDIMS];		/*zero			*/
+    hid_t reg_id;               /* ID of temporary region buffer */
     H5S_hyper_region_t *regions;  /* Pointer to array of hyperslab nodes overlapped */
     size_t num_regions;         /* number of regions overlapped */
     size_t i;                   /* Counters */
@@ -1206,10 +1438,13 @@ H5S_hyper_mwrite (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
 
     /* Get a sorted list (in the next dimension down) of the regions which */
     /*  overlap the current index in this dim */
-    if((regions=H5S_hyper_get_regions(&num_regions,dim,
+    if((reg_id=H5S_hyper_get_regions(&num_regions,dim,
             fhyper_info->space->select.sel_info.hyper.hyper_lst->count,
             fhyper_info->lo_bounds, fhyper_info->hi_bounds,
-            fhyper_info->iter->hyp.pos,fhyper_info->space->select.offset))!=NULL) {
+            fhyper_info->iter->hyp.pos,fhyper_info->space->select.offset))!=FAIL) {
+
+        /* Get the pointer to the actual regions array */
+        regions=H5TB_buf_ptr(reg_id);
 
 #ifdef QAK
 	printf("%s: check 2.0, rank=%d\n",
@@ -1242,10 +1477,6 @@ H5S_hyper_mwrite (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
 			   fhyper_info->space->extent.u.simple.rank);
             hsize[fhyper_info->space->extent.u.simple.rank]=fhyper_info->elmt_size;
 
-            /* Set the memory offset to the origin */
-            HDmemset (zero, 0, ((fhyper_info->space->extent.u.simple.rank+1)*
-				sizeof(*zero)));
-
 #ifdef QAK
 	    printf("%s: check 3.0\n",FUNC);
 #endif /* QAK */
@@ -1323,8 +1554,8 @@ H5S_hyper_mwrite (intn dim, H5S_hyper_fhyper_info_t *fhyper_info)
             } /* end for */
         } /* end else */
 
-        /* Free the region space */
-        H5MM_xfree(regions);
+        /* Release the temporary buffer */
+        H5TB_release_buf(reg_id);
     } /* end if */
 
     FUNC_LEAVE (num_read);
@@ -1545,6 +1776,13 @@ H5S_hyper_add (H5S_t *space, const hssize_t *start, const hsize_t *size)
         elem_count*=size[i];
     } /* end for */
 
+    /* Initialize caching parameters */
+    slab->cinfo.cached=0;
+    slab->cinfo.size=elem_count;
+    slab->cinfo.left=0;
+    slab->cinfo.block_id=(-1);
+    slab->cinfo.block=slab->cinfo.pos=NULL;
+
 #ifdef QAK
     printf("%s: check 3.0, lo_bounds=%p, hi_bounds=%p\n",
 	   FUNC, space->select.sel_info.hyper.hyper_lst->lo_bounds,
@@ -1942,6 +2180,7 @@ H5S_hyper_copy (H5S_t *dst, const H5S_t *src)
         if((new = H5MM_malloc(sizeof(H5S_hyper_node_t)))==NULL)
             HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL,
                 "can't allocate point node");
+        HDmemcpy(new,curr,sizeof(H5S_hyper_node_t));    /* copy caching information */
         if((new->start = H5MM_malloc(src->extent.u.simple.rank*sizeof(hssize_t)))==NULL)
             HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL,
                 "can't allocate coordinate information");
diff --git a/src/H5Spoint.c b/src/H5Spoint.c
index cf6fdee..f3edd63 100644
--- a/src/H5Spoint.c
+++ b/src/H5Spoint.c
@@ -12,6 +12,7 @@
 #include <H5MMprivate.h>
 #include <H5Sprivate.h>
 #include <H5Vprivate.h>
+#include <H5Dprivate.h>
 
 /* Interface initialization */
 #define PABLO_MASK      H5S_point_mask
@@ -27,14 +28,14 @@ static size_t H5S_point_fgath (H5F_t *f, const struct H5O_layout_t *layout,
 			       const struct H5O_efl_t *efl, size_t elmt_size,
 			       const H5S_t *file_space,
 			       H5S_sel_iter_t *file_iter, size_t nelmts,
-			       const H5D_transfer_t xfer_mode,
+			       const void *_xfer_parms,
 			       void *buf/*out*/);
 static herr_t H5S_point_fscat (H5F_t *f, const struct H5O_layout_t *layout,
 			       const struct H5O_pline_t *pline,
 			       const struct H5O_efl_t *efl, size_t elmt_size,
 			       const H5S_t *file_space,
 			       H5S_sel_iter_t *file_iter, size_t nelmts,
-			       const H5D_transfer_t xfer_mode,
+			       const void *_xfer_parms,
 			       const void *buf);
 static size_t H5S_point_mgath (const void *_buf, size_t elmt_size,
 			       const H5S_t *mem_space,
@@ -266,9 +267,10 @@ H5S_point_fgath (H5F_t *f, const struct H5O_layout_t *layout,
 		 const struct H5O_pline_t *pline,
 		 const struct H5O_efl_t *efl, size_t elmt_size,
 		 const H5S_t *file_space, H5S_sel_iter_t *file_iter,
-		 size_t nelmts, const H5D_transfer_t xfer_mode,
+		 size_t nelmts, const void *_xfer_parms,
 		 void *_buf/*out*/)
 {
+    const H5D_xfer_t *xfer_parms=(const H5D_xfer_t *)_xfer_parms;   /* Coerce the type */
     hssize_t	file_offset[H5O_LAYOUT_NDIMS];	/*offset of slab in file*/
     hsize_t	hsize[H5O_LAYOUT_NDIMS];	/*size of hyperslab	*/
     hssize_t	zero[H5O_LAYOUT_NDIMS];		/*zero			*/
@@ -317,7 +319,7 @@ H5S_point_fgath (H5F_t *f, const struct H5O_layout_t *layout,
 
             /* Go read the point */
             if (H5F_arr_read (f, layout, pline, efl, hsize, hsize, zero,
-			      file_offset, xfer_mode, buf/*out*/)<0) {
+			      file_offset, xfer_parms->xfer_mode, buf/*out*/)<0) {
                 HRETURN_ERROR (H5E_DATASPACE, H5E_READERROR, 0, "read error");
             }
 
@@ -375,9 +377,10 @@ H5S_point_fscat (H5F_t *f, const struct H5O_layout_t *layout,
 		 const struct H5O_pline_t *pline,
 		 const struct H5O_efl_t *efl, size_t elmt_size,
 		 const H5S_t *file_space, H5S_sel_iter_t *file_iter,
-		 size_t nelmts, const H5D_transfer_t xfer_mode,
+		 size_t nelmts, const void *_xfer_parms,
 		 const void *_buf)
 {
+    const H5D_xfer_t *xfer_parms=(const H5D_xfer_t *)_xfer_parms;   /* Coerce the type */
     hssize_t	file_offset[H5O_LAYOUT_NDIMS];	/*offset of hyperslab	*/
     hsize_t	hsize[H5O_LAYOUT_NDIMS];	/*size of hyperslab	*/
     hssize_t	zero[H5O_LAYOUT_NDIMS];		/*zero vector		*/
@@ -445,7 +448,7 @@ H5S_point_fscat (H5F_t *f, const struct H5O_layout_t *layout,
 #endif /* QAK */
         /* Go write the point */
         if (H5F_arr_write (f, layout, pline, efl, hsize, hsize, zero,
-			   file_offset, xfer_mode, buf)<0) {
+			   file_offset, xfer_parms->xfer_mode, buf)<0) {
             HRETURN_ERROR (H5E_DATASPACE, H5E_WRITEERROR, 0, "write error");
         }
 
diff --git a/src/H5Sprivate.h b/src/H5Sprivate.h
index 862de9a..95c6ae6 100644
--- a/src/H5Sprivate.h
+++ b/src/H5Sprivate.h
@@ -71,19 +71,28 @@ typedef struct {
     H5S_pnt_node_t *head;   /* Pointer to head of point list */
 } H5S_pnt_list_t;
 
+/* Node in hyperslab selection list */
+typedef struct H5S_hyper_node_tag {
+    hssize_t *start;    /* Pointer to a corner of a hyperslab closest to the origin */
+    hssize_t *end;      /* Pointer to a corner of a hyperslab furthest from the origin */
+    struct {
+        uintn cached;   /* Flag to indicate that the block is cached (during I/O only) */
+        uintn size;     /* Size of cached block (in elements) */
+        uintn left;     /* Elements left to access in block */
+        hid_t block_id; /* Temporary buffer ID */
+        uint8 *block;   /* Pointer into temporary buffer for cache */
+        uint8 *pos;     /* Pointer to current location within block */
+    } cinfo;
+    struct H5S_hyper_node_tag *next;  /* pointer to next hyperslab in list */
+} H5S_hyper_node_t;
+
 /* Region in dimension */
 typedef struct H5S_hyper_region_tag {
     hssize_t start;    /* The low bound of a region in a dimension */
     hssize_t end;      /* The high bound of a region in a dimension */
+    H5S_hyper_node_t *node; /* pointer to the node the region is in */
 } H5S_hyper_region_t;
 
-/* Node in hyperslab selection list */
-typedef struct H5S_hyper_node_tag {
-    hssize_t *start;   /* Pointer to a corner of a hyperslab closest to the origin */
-    hssize_t *end;     /* Pointer to a corner of a hyperslab furthest from the origin */
-    struct H5S_hyper_node_tag *next;  /* pointer to next hyperslab in list */
-} H5S_hyper_node_t;
-
 /* Information about hyperslab boundary and pointer to hyperslab node */
 typedef struct {
     hssize_t bound;         /* Location of boundary */
@@ -183,7 +192,7 @@ typedef struct H5S_fconv_t {
 		   const struct H5O_pline_t *pline,
 		   const struct H5O_efl_t *efl, size_t elmt_size,
 		   const H5S_t *file_space, H5S_sel_iter_t *file_iter,
-		   size_t nelmts, const H5D_transfer_t xfer_mode,
+		   size_t nelmts, const void *xfer_parms,
 		   void *tconv_buf/*out*/);
 
     /* Scatter elements from type conversion buffer to disk */
@@ -191,7 +200,7 @@ typedef struct H5S_fconv_t {
 		   const struct H5O_pline_t *pline,
 		   const struct H5O_efl_t *efl, size_t elmt_size,
 		   const H5S_t *file_space, H5S_sel_iter_t *file_iter,
-		   size_t nelmts, const H5D_transfer_t xfer_mode,
+		   size_t nelmts, const void *xfer_parms,
 		   const void *tconv_buf);
 } H5S_fconv_t;
 
@@ -276,10 +285,6 @@ extern const H5S_mconv_t	H5S_ALL_MCONV[];
 extern const H5S_fconv_t	H5S_HYPER_FCONV[];
 extern const H5S_mconv_t	H5S_HYPER_MCONV[];
 
-#ifdef LATER_ROBB
-#endif
-
-
 H5S_t *H5S_create (H5S_class_t type);
 H5S_t *H5S_copy (const H5S_t *src);
 herr_t H5S_close_simple (H5S_simple_t *simple);
diff --git a/src/H5Sselect.c b/src/H5Sselect.c
index 4d9a84d..0620570 100644
--- a/src/H5Sselect.c
+++ b/src/H5Sselect.c
@@ -14,6 +14,7 @@
 #include <H5MMprivate.h>
 #include <H5Sprivate.h>
 #include <H5Vprivate.h>
+#include <H5TBprivate.h>
 
 /* Interface initialization */
 #define PABLO_MASK      H5S_select_mask
@@ -293,7 +294,7 @@ H5S_select_hyperslab (H5S_t *space, H5S_seloper_t op,
 		      const hsize_t count[/*space_id*/],
 		      const hsize_t block[/*space_id*/])
 {
-    
+    hid_t stride_id=FAIL,block_id=FAIL; /* Stride & block temp. buffer IDs */
     hsize_t *_stride=NULL;        /* Stride array */
     hsize_t *_block=NULL;        /* Block size array */
     hssize_t slab[H5O_LAYOUT_NDIMS]; /* Location of the block to add for strided selections */
@@ -316,7 +317,8 @@ H5S_select_hyperslab (H5S_t *space, H5S_seloper_t op,
     if(stride==NULL) {
         hssize_t fill=1;
 
-        if((_stride = H5MM_malloc(sizeof(hssize_t)*space->extent.u.simple.rank))==NULL)
+        /* Allocate temporary buffer */
+        if((stride_id = H5TB_get_buf(sizeof(hssize_t)*space->extent.u.simple.rank,0,(void **)&_stride)) ==FAIL)
             HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL,
                 "can't allocate stride vector");
         H5V_array_fill(_stride,&fill,sizeof(hssize_t),space->extent.u.simple.rank);
@@ -327,7 +329,7 @@ H5S_select_hyperslab (H5S_t *space, H5S_seloper_t op,
     if(block==NULL) {
         hssize_t fill=1;
 
-        if((_block = H5MM_malloc(sizeof(hssize_t)*space->extent.u.simple.rank))==NULL)
+        if((block_id = H5TB_get_buf(sizeof(hssize_t)*space->extent.u.simple.rank,0,(void **)&_block))==FAIL)
             HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL,
                 "can't allocate block vector");
         H5V_array_fill(_block,&fill,sizeof(hssize_t),space->extent.u.simple.rank);
@@ -444,8 +446,8 @@ H5S_select_hyperslab (H5S_t *space, H5S_seloper_t op,
 #endif /* QAK */
 
 done:
-    H5MM_xfree(_stride);
-    H5MM_xfree(_block);
+    if(_stride!=NULL) H5TB_release_buf(stride_id);
+    if(_block!=NULL) H5TB_release_buf(block_id);
     FUNC_LEAVE (ret_value);
 }
 
diff --git a/src/H5TB.c b/src/H5TB.c
index d625bfc..5079d27 100644
--- a/src/H5TB.c
+++ b/src/H5TB.c
@@ -18,11 +18,11 @@
  * Purpose:		Temporary buffer management functions
  *
  * Library Public API Functions:
- *  H5TBget_buf     - Get an ID for a temporary buffer
- *  H5TBbuf_ptr     - Get a pointer to the temporary buffer's memory
- *  H5TBresize_buf  - Resize a temporary buffer
- *  H5TBgarbage_coll- Free all unused temporary buffers
- *  H5TBrelease_buf - Release temporary buffer
+ *  H5TB_get_buf     - Get an ID for a temporary buffer
+ *  H5TB_buf_ptr     - Get a pointer to the temporary buffer's memory
+ *  H5TB_resize_buf  - Resize a temporary buffer
+ *  H5TB_garbage_coll- Free all unused temporary buffers
+ *  H5TB_release_buf - Release temporary buffer
  *
  * Modifications:	
  *
@@ -112,8 +112,25 @@ H5TB_init_interface(void)
 static void
 H5TB_term_interface(void)
 {
+    H5TB_t *curr=H5TB_list_head,       /* pointer to current temp. buffer */
+        *next;                          /* pointer to next temp. buffer */
+
     /* Destroy the atom group */
+    H5I_destroy_group(H5_TEMPBUF);
+
     /* Step through the list and free the buffers */
+    while(curr!=NULL) {
+        next=curr->next;
+
+        if(curr->buf!=NULL)
+            H5MM_xfree(curr->buf);
+        H5MM_xfree(curr);
+
+        curr=next;
+    } /* end while */
+
+    /* Reset head & tail pointers */
+    H5TB_list_head=H5TB_list_tail=NULL;
 }
 
 /*-------------------------------------------------------------------------
@@ -147,14 +164,16 @@ herr_t H5TB_close(H5TB_t *tb)
 
 /*--------------------------------------------------------------------------
  NAME
-    H5TBget_buf
+    H5TB_get_buf
  PURPOSE
     Get an ID for a temporary buffer
  USAGE
-    hid_t H5TBget_buf(size,resize)
+    hid_t H5TB_get_buf(size,resize,ptr)
         hsize_t size;       IN: Minimum size of buffer requested
         hbool_t resize;     IN: Whether to resize an existing buffer or get a
                                 new buffer if one doesn't match the correct size
+        void **ptr;         OUT: Pointer to a pointer to set to the buffer
+                                address, if not NULL
  RETURNS
     Valid buffer ID on success, negative on failure
  DESCRIPTION
@@ -169,17 +188,16 @@ herr_t H5TB_close(H5TB_t *tb)
  REVISION LOG
 --------------------------------------------------------------------------*/
 hid_t
-H5TBget_buf(hsize_t size, hbool_t resize)
+H5TB_get_buf(hsize_t size, hbool_t resize, void **ptr)
 {
     hid_t	ret_value = FAIL;
     H5TB_t *curr=H5TB_list_head,       /* pointer to current temp. buffer */
         *new;                          /* pointer to a newly created temp. buffer */
 
-    FUNC_ENTER (H5TBget_buf, FAIL);
-    H5TRACE2("i","hb",size,resize);
+    FUNC_ENTER (H5TB_get_buf, FAIL);
 
     while(curr!=NULL) {
-        if(!curr->inuse && size<curr->size)
+        if(!curr->inuse && size<=curr->size)
             break;
         curr=curr->next;
     } /* end while */
@@ -250,6 +268,7 @@ H5TBget_buf(hsize_t size, hbool_t resize)
 
                     /* set this so we can fall through to getting the ID */
                     curr=new;
+                    break;
                 } /* end if */
             } /* end for */
 
@@ -270,19 +289,23 @@ H5TBget_buf(hsize_t size, hbool_t resize)
         HGOTO_ERROR (H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to register temp. buffer atom");
     }
 
+    /* Assign the pointer to the buffer, if requested */
+    if(ptr!=NULL)
+        *ptr=curr->buf;
+
 done:
     if (ret_value < 0) {
     }
     FUNC_LEAVE(ret_value);
-} /* H5TBget_buf() */
+} /* H5TB_get_buf() */
 
 /*--------------------------------------------------------------------------
  NAME
-    H5TBbuf_ptr
+    H5TB_buf_ptr
  PURPOSE
     Get the pointer to a temp. buffer memory
  USAGE
-    void *H5TBbuf_ptr(tbuf_id)
+    void *H5TB_buf_ptr(tbuf_id)
         hid_t tbuf_id;       IN: Temp. buffer ID
  RETURNS
     Non-NULL pointer to buffer memory on success, NULL on failure
@@ -294,12 +317,12 @@ done:
  REVISION LOG
 --------------------------------------------------------------------------*/
 void *
-H5TBbuf_ptr(hid_t tbuf_id)
+H5TB_buf_ptr(hid_t tbuf_id)
 {
     void *ret_value = NULL;
     H5TB_t *tbuf;               /* Pointer to temporary buffer */
 
-    FUNC_ENTER (H5TBbuf_ptr, NULL);
+    FUNC_ENTER (H5TB_buf_ptr, NULL);
 
     if (H5_TEMPBUF != H5I_group(tbuf_id) ||
             NULL == (tbuf = H5I_object(tbuf_id))) {
@@ -314,15 +337,15 @@ done:
     if (ret_value == NULL) {
     }
     FUNC_LEAVE(ret_value);
-} /* H5TBbuf_ptr() */
+} /* H5TB_buf_ptr() */
 
 /*--------------------------------------------------------------------------
  NAME
-    H5TBresize_ptr
+    H5TB_resize_buf
  PURPOSE
     Resize a temp. buffer to a new size
  USAGE
-    herr_t H5TBresize_ptr(tbid, size)
+    herr_t H5TB_resize_buf(tbid, size)
         hid_t tbid;       IN: Temp. buffer ID to resize
         hsize_t size;     IN: New size of temp. buffer
  RETURNS
@@ -335,15 +358,14 @@ done:
  REVISION LOG
 --------------------------------------------------------------------------*/
 herr_t
-H5TBresize_ptr(hid_t tbuf_id, hsize_t size)
+H5TB_resize_buf(hid_t tbuf_id, hsize_t size)
 {
     herr_t ret_value = FAIL;
     H5TB_t *tbuf,               /* Pointer to temporary buffer */
         *curr;                  /* Pointer to temp. buffer node */
     void * old_ptr;             /* Pointer to the previous buffer */
 
-    FUNC_ENTER (H5TBresize_ptr, FAIL);
-    H5TRACE2("e","ih",tbuf_id,size);
+    FUNC_ENTER (H5TB_resize_buf, FAIL);
 
     if (H5_TEMPBUF != H5I_group(tbuf_id) ||
             NULL == (tbuf = H5I_object(tbuf_id))) {
@@ -410,15 +432,15 @@ done:
     if (ret_value == FAIL) {
     }
     FUNC_LEAVE(ret_value);
-} /* H5TBresize_ptr() */
+} /* H5TB_resize_buf() */
 
 /*--------------------------------------------------------------------------
  NAME
-    H5TBgarbage_coll
+    H5TB_garbage_coll
  PURPOSE
     Release all unused temporary buffers
  USAGE
-    herr_t H5TBgarbase_coll()
+    herr_t H5TB_garbase_coll()
  RETURNS
     non-negative on success, negative on failure
  DESCRIPTION
@@ -430,13 +452,12 @@ done:
  REVISION LOG
 --------------------------------------------------------------------------*/
 herr_t
-H5TBgarbage_coll(void)
+H5TB_garbage_coll(void)
 {
     herr_t ret_value = FAIL;
     H5TB_t *curr,*next;      /* Current temp. buffer node */
 
-    FUNC_ENTER (H5TBgarbage_coll, FAIL);
-    H5TRACE0("e","");
+    FUNC_ENTER (H5TB_garbage_coll, FAIL);
 
     /*
      * Step through the list, remove each unused node, repair the list and
@@ -474,15 +495,15 @@ done:
     if (ret_value == FAIL) {
     }
     FUNC_LEAVE(ret_value);
-}   /* H5TBgarbage_coll() */
+}   /* H5TB_garbage_coll() */
 
 /*--------------------------------------------------------------------------
  NAME
-    H5TBrelease_buf
+    H5TB_release_buf
  PURPOSE
     Release a temp. buffer back to the list of unused ones.
  USAGE
-    herr_t H5TBrelease_buf(tbuf_id)
+    herr_t H5TB_release_buf(tbuf_id)
         hid_t tbuf_id;       IN: Temp. buffer ID to release
  RETURNS
     non-negative on success, negative on failure
@@ -494,16 +515,15 @@ done:
  REVISION LOG
 --------------------------------------------------------------------------*/
 herr_t
-H5TBrelease_buf(hid_t tbuf_id)
+H5TB_release_buf(hid_t tbuf_id)
 {
     herr_t ret_value = FAIL;
     H5TB_t *tbuf;               /* Pointer to temporary buffer */
 
-    FUNC_ENTER (H5TBresize_ptr, FAIL);
-    H5TRACE1("e","i",tbuf_id);
+    FUNC_ENTER (H5TB_release_buf, FAIL);
 
     if (H5_TEMPBUF != H5I_group(tbuf_id) ||
-            NULL == (tbuf = H5I_object(tbuf_id))) {
+            NULL == (tbuf = H5I_remove(tbuf_id))) {
         HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a temp. buffer");
     }
 
@@ -518,5 +538,5 @@ done:
     if (ret_value == FAIL) {
     }
     FUNC_LEAVE(ret_value);
-} /* H5TBresize_ptr() */
+} /* H5TB_release_buf() */
 
diff --git a/src/H5TBprivate.h b/src/H5TBprivate.h
index 2d48b1c..2ed46d9 100644
--- a/src/H5TBprivate.h
+++ b/src/H5TBprivate.h
@@ -17,10 +17,10 @@
 #define _H5TBprivate_H
 
 /* Functions defined in H5TB.c */
-hid_t H5TBget_buf(hsize_t size, hbool_t resize);
-void *H5TBbuf_ptr(hid_t tbid);
-herr_t H5TBresize_ptr(hid_t tbid, hsize_t size);
-herr_t H5TBgarbage_coll(void);
-herr_t H5TBrelease_buf(hid_t tbid);
+hid_t H5TB_get_buf(hsize_t size, hbool_t resize, void **ptr);
+void *H5TB_buf_ptr(hid_t tbid);
+herr_t H5TB_resize_buf(hid_t tbid, hsize_t size);
+herr_t H5TB_garbage_coll(void);
+herr_t H5TB_release_buf(hid_t tbid);
 
 #endif
diff --git a/src/H5V.c b/src/H5V.c
index a72452f..7708794 100644
--- a/src/H5V.c
+++ b/src/H5V.c
@@ -170,11 +170,11 @@ H5V_hyper_stride(intn n, const hsize_t *size,
 
     /* others */
     for (i=n-2, acc=1; i>=0; --i) {
-	hsize_t tmp = acc * (total_size[i+1] - size[i+1]);
-	assert (tmp<((hsize_t)1<<(8*sizeof(hssize_t)-1)));
-	stride[i] = (hssize_t)tmp; /*overflow checked*/
-	acc *= total_size[i+1];
-	skip += acc * (offset ? offset[i] : 0);
+        hsize_t tmp = acc * (total_size[i+1] - size[i+1]);
+        assert (tmp<((hsize_t)1<<(8*sizeof(hssize_t)-1)));
+        stride[i] = (hssize_t)tmp; /*overflow checked*/
+        acc *= total_size[i+1];
+        skip += acc * (offset ? offset[i] : 0);
     }
 
     FUNC_LEAVE(skip);
@@ -410,26 +410,42 @@ H5V_hyper_copy(intn n, const hsize_t *_size,
 	assert(src_size[i] > 0);
     }
 #endif
-#ifdef QAK
-    {
-	intn i;
-
-	printf("%s: n=%d, _dst=%p, _src=%p\n",FUNC,(int)n,_dst,_src);
-	for(i=0; i<n; i++) {
-	    printf("%d: size=%d, dst_size=%d, dst_offset=%d, src_size=%d, "
-		   "src_offset=%d\n",
-		   i, (int)size[i], (int)dst_size[i], (int)dst_offset[i],
-		   (int)src_size[i], (int)src_offset[i]);
-	} /* end for */
-    }
-#endif /* QAK */
 
     /* Copy the size vector so we can modify it */
     H5V_vector_cpy(n, size, _size);
 
     /* Compute stride vectors for source and destination */
+#ifdef NO_INLINED_CODE
     dst_start = H5V_hyper_stride(n, size, dst_size, dst_offset, dst_stride);
     src_start = H5V_hyper_stride(n, size, src_size, src_offset, src_stride);
+#else /* NO_INLINED_CODE */
+    /* in-line version of two calls to H5V_hyper_stride() */
+    {
+        hsize_t	    dst_acc;	/*accumulator				*/
+        hsize_t	    src_acc;	/*accumulator				*/
+        int		    i;		/*counter				*/
+
+        /* init */
+        dst_stride[n-1] = 1;
+        src_stride[n-1] = 1;
+        dst_start = dst_offset ? dst_offset[n-1] : 0;
+        src_start = src_offset ? src_offset[n-1] : 0;
+
+        /* others */
+        for (i=n-2, dst_acc=1, src_acc=1; i>=0; --i) {
+            hsize_t tmp1 = dst_acc * (dst_size[i+1] - size[i+1]);
+            hsize_t tmp2 = src_acc * (src_size[i+1] - size[i+1]);
+            assert (tmp1<((hsize_t)1<<(8*sizeof(hssize_t)-1)));
+            assert (tmp2<((hsize_t)1<<(8*sizeof(hssize_t)-1)));
+            dst_stride[i] = (hssize_t)tmp1; /*overflow checked*/
+            src_stride[i] = (hssize_t)tmp2; /*overflow checked*/
+            dst_acc *= dst_size[i+1];
+            src_acc *= src_size[i+1];
+            dst_start += dst_acc * (dst_offset ? dst_offset[i] : 0);
+            src_start += src_acc * (src_offset ? src_offset[i] : 0);
+        }
+    }
+#endif /* NO_INLINED_CODE */
 
     /* Optimize the strides as a pair */
     H5V_stride_optimize2(&n, &elmt_size, size, dst_stride, src_stride);