[svn-r11967] Purpose:

    New feature

Description:
    Check in initial "fractal heap" code, for supporting the group redesign.

    Also, remove some remnants of the segmented heap/block tracker/B+tree code
which I didn't find during the last pass.

Platforms tested:
    FreeBSD 4.11 (sleipnir)
    Mac OSX (amazon)
    Linux 2.4

23 files changed, 1528 insertions, 123 deletions

diff --git a/MANIFEST b/MANIFEST
index 4cbd067..a517fdb 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -492,6 +492,13 @@
 ./src/H5Gstab.c
 ./src/H5Gtest.c
 ./src/H5Gtraverse.c
+./src/H5HF.c
+./src/H5HFcache.c
+./src/H5HFdbg.c
+./src/H5HFpkg.h
+./src/H5HFprivate.h
+./src/H5HFpublic.h
+./src/H5HFtest.c
 ./src/H5HG.c
 ./src/H5HGdbg.c
 ./src/H5HGpkg.h
@@ -641,6 +648,7 @@
 ./test/family_v1.6_00001.h5
 ./test/family_v1.6_00002.h5
 ./test/family_v1.6_00003.h5
+./test/fheap.c
 ./test/fill_old.h5
 ./test/fillval.c
 ./test/flush1.c
diff --git a/src/H5AC.c b/src/H5AC.c
index aeb78b6..2d10b03 100644
--- a/src/H5AC.c
+++ b/src/H5AC.c
@@ -742,6 +742,7 @@ static const char * H5AC_entry_type_names[H5AC_NTYPES] =
     "v2 B-tree headers",
     "v2 B-tree internal nodes",
     "v2 B-tree leaf nodes",
+    "fractal heap headers",
     "test entry"	/* for testing only -- not used for actual files */
 };
 
diff --git a/src/H5ACprivate.h b/src/H5ACprivate.h
index 8f30c28..9817a4a 100644
--- a/src/H5ACprivate.h
+++ b/src/H5ACprivate.h
@@ -50,6 +50,7 @@ typedef enum {
     H5AC_BT2_INT_ID,	/*v2 B-tree internal node		     */
     H5AC_BT2_LEAF_ID,	/*v2 B-tree leaf node			     */
     H5AC_TEST_ID,	/*test entry -- not used for actual files    */
+    H5AC_FHEAP_HDR_ID,	/*fractal heap header			     */
     H5AC_NTYPES		/* Number of types, must be last             */
 } H5AC_type_t;
 
diff --git a/src/H5Cpkg.h b/src/H5Cpkg.h
index 3e2c049..7ee4647 100644
--- a/src/H5Cpkg.h
+++ b/src/H5Cpkg.h
@@ -609,7 +609,7 @@
  ****************************************************************************/
 
 #define H5C__H5C_T_MAGIC	0x005CAC0E
-#define H5C__MAX_NUM_TYPE_IDS	9
+#define H5C__MAX_NUM_TYPE_IDS	10
 #define H5C__PREFIX_LEN		32
 
 struct H5C_t
diff --git a/src/H5Edefin.h b/src/H5Edefin.h
index 12582f4..82a74b8 100644
--- a/src/H5Edefin.h
+++ b/src/H5Edefin.h
@@ -40,7 +40,6 @@ hid_t H5E_OHDR_g           = FAIL;      /* Object header */
 hid_t H5E_ATOM_g           = FAIL;      /* Object atom */
 hid_t H5E_ATTR_g           = FAIL;      /* Attribute */
 hid_t H5E_IO_g             = FAIL;      /* Low-level I/O */
-hid_t H5E_BLKTRK_g         = FAIL;      /* Block tracker */
 hid_t H5E_SLIST_g          = FAIL;      /* Skip Lists */
 hid_t H5E_EFL_g            = FAIL;      /* External file list */
 hid_t H5E_TST_g            = FAIL;      /* Ternary Search Trees */
@@ -150,9 +149,6 @@ hid_t H5E_CANTUNPROTECT_g  = FAIL;      /* Unable to unprotect metadata */
 hid_t H5E_MPI_g            = FAIL;      /* Some MPI function failed */
 hid_t H5E_MPIERRSTR_g      = FAIL;      /* MPI Error String */
 
-/* Block tracker errors */
-hid_t H5E_OVERLAPS_g       = FAIL;      /* Blocks overlap */
-
 /* Dataspace errors */
 hid_t H5E_CANTCLIP_g       = FAIL;      /* Can't clip hyperslab region */
 hid_t H5E_CANTCOUNT_g      = FAIL;      /* Can't count elements */
diff --git a/src/H5Einit.h b/src/H5Einit.h
index bf31088..b2a4563 100644
--- a/src/H5Einit.h
+++ b/src/H5Einit.h
@@ -123,11 +123,6 @@ if((msg = H5E_create_msg(cls, H5E_MAJOR, "Low-level I/O"))==NULL)
     HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
 if((H5E_IO_g = H5I_register(H5I_ERROR_MSG, msg))<0)
     HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
-assert(H5E_BLKTRK_g==(-1));
-if((msg = H5E_create_msg(cls, H5E_MAJOR, "Block tracker"))==NULL)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
-if((H5E_BLKTRK_g = H5I_register(H5I_ERROR_MSG, msg))<0)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
 assert(H5E_SLIST_g==(-1));
 if((msg = H5E_create_msg(cls, H5E_MAJOR, "Skip Lists"))==NULL)
     HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
@@ -552,13 +547,6 @@ if((msg = H5E_create_msg(cls, H5E_MINOR, "MPI Error String"))==NULL)
 if((H5E_MPIERRSTR_g = H5I_register(H5I_ERROR_MSG, msg))<0)
     HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
 
-/* Block tracker errors */
-assert(H5E_OVERLAPS_g==(-1));
-if((msg = H5E_create_msg(cls, H5E_MINOR, "Blocks overlap"))==NULL)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
-if((H5E_OVERLAPS_g = H5I_register(H5I_ERROR_MSG, msg))<0)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
-
 /* Dataspace errors */
 assert(H5E_CANTCLIP_g==(-1));
 if((msg = H5E_create_msg(cls, H5E_MINOR, "Can't clip hyperslab region"))==NULL)
diff --git a/src/H5Epubgen.h b/src/H5Epubgen.h
index 4245a5c..c846a67 100644
--- a/src/H5Epubgen.h
+++ b/src/H5Epubgen.h
@@ -43,7 +43,6 @@
 #define H5E_ATOM             (H5OPEN H5E_ATOM_g)
 #define H5E_ATTR             (H5OPEN H5E_ATTR_g)
 #define H5E_IO               (H5OPEN H5E_IO_g)
-#define H5E_BLKTRK           (H5OPEN H5E_BLKTRK_g)
 #define H5E_SLIST            (H5OPEN H5E_SLIST_g)
 #define H5E_EFL              (H5OPEN H5E_EFL_g)
 #define H5E_TST              (H5OPEN H5E_TST_g)
@@ -71,7 +70,6 @@ H5_DLLVAR hid_t H5E_OHDR_g;          /* Object header */
 H5_DLLVAR hid_t H5E_ATOM_g;          /* Object atom */
 H5_DLLVAR hid_t H5E_ATTR_g;          /* Attribute */
 H5_DLLVAR hid_t H5E_IO_g;            /* Low-level I/O */
-H5_DLLVAR hid_t H5E_BLKTRK_g;        /* Block tracker */
 H5_DLLVAR hid_t H5E_SLIST_g;         /* Skip Lists */
 H5_DLLVAR hid_t H5E_EFL_g;           /* External file list */
 H5_DLLVAR hid_t H5E_TST_g;           /* Ternary Search Trees */
@@ -254,10 +252,6 @@ H5_DLLVAR hid_t H5E_CANTUNPROTECT_g; /* Unable to unprotect metadata */
 H5_DLLVAR hid_t H5E_MPI_g;           /* Some MPI function failed */
 H5_DLLVAR hid_t H5E_MPIERRSTR_g;     /* MPI Error String */
 
-/* Block tracker errors */
-#define H5E_OVERLAPS         (H5OPEN H5E_OVERLAPS_g)
-H5_DLLVAR hid_t H5E_OVERLAPS_g;      /* Blocks overlap */
-
 /* Dataspace errors */
 #define H5E_CANTCLIP         (H5OPEN H5E_CANTCLIP_g)
 #define H5E_CANTCOUNT        (H5OPEN H5E_CANTCOUNT_g)
diff --git a/src/H5Eterm.h b/src/H5Eterm.h
index 00eee70..66307f9 100644
--- a/src/H5Eterm.h
+++ b/src/H5Eterm.h
@@ -41,7 +41,6 @@ H5E_OHDR_g=
 H5E_ATOM_g=    
 H5E_ATTR_g=    
 H5E_IO_g=    
-H5E_BLKTRK_g=    
 H5E_SLIST_g=    
 H5E_EFL_g=    
 H5E_TST_g=    
@@ -152,9 +151,6 @@ H5E_CANTUNPROTECT_g=
 H5E_MPI_g=    
 H5E_MPIERRSTR_g=
 
-/* Block tracker errors */    
-H5E_OVERLAPS_g=
-
 /* Dataspace errors */    
 H5E_CANTCLIP_g=    
 H5E_CANTCOUNT_g=    
diff --git a/src/H5FDpublic.h b/src/H5FDpublic.h
index 285404a..774b3f6 100644
--- a/src/H5FDpublic.h
+++ b/src/H5FDpublic.h
@@ -43,18 +43,21 @@ typedef enum H5FD_mem_t {
     H5FD_MEM_NTYPES				/*must be last*/
 } H5FD_mem_t;
 
-/* Map "block tracker" header blocks to 'ohdr' type file memory, since its
- * a fair amount of work to add a new kind of file memory, they are similar
- * enough to object headers and probably too minor to deserve their own type. -QAK */
-#define H5FD_MEM_BLKTRK H5FD_MEM_OHDR
-
-/* Map "segmented heap" header blocks to 'ohdr' type file memory, since its
- * a fair amount of work to add a new kind of file memory, they are similar
+/* Map "fractal heap" header blocks to 'ohdr' type file memory, since its
+ * a fair amount of work to add a new kind of file memory and they are similar
  * enough to object headers and probably too minor to deserve their own type.
- * Map "segmented heap" blocks to 'lheap' type file memory, since they will be
- * replacing local heaps. -QAK */
-#define H5FD_MEM_SHEAP_HDR      H5FD_MEM_OHDR
-#define H5FD_MEM_SHEAP_BLOCK    H5FD_MEM_LHEAP
+ *
+ * Map "fractal heap" indirect blocks to 'ohdr' type file memory, since they
+ * are similar to fractal heap header blocks.
+ *
+ * Map "fractal heap" direct blocks to 'lheap' type file memory, since they
+ * will be replacing local heaps.
+ *
+ *      -QAK
+ */
+#define H5FD_MEM_FHEAP_HDR      H5FD_MEM_OHDR
+#define H5FD_MEM_FHEAP_INDIRECT H5FD_MEM_OHDR
+#define H5FD_MEM_FHEAP_DIRECT   H5FD_MEM_LHEAP
 
 /*
  * A free-list map which maps all types of allocation requests to a single
diff --git a/src/H5HF.c b/src/H5HF.c
new file mode 100644
index 0000000..1fe38cb
--- /dev/null
+++ b/src/H5HF.c
@@ -0,0 +1,271 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:		H5HF.c
+ *			Feb 24 2006
+ *			Quincey Koziol <koziol@ncsa.uiuc.edu>
+ *
+ * Purpose:		Implements a "fractal heap" for storing variable-
+ *                      length objects in a file.
+ *
+ *                      Please see the documentation in:
+ *                      doc/html/TechNotes/FractalHeap.html for a full description
+ *                      of how they work, etc.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#define H5HF_PACKAGE		/*suppress error about including H5HFpkg  */
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5HFpkg.h"		/* Fractal heaps			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5MFprivate.h"	/* File memory management		*/
+
+/****************/
+/* Local Macros */
+/****************/
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+static herr_t H5HF_shared_free(void *_shared);
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+/* Declare a free list to manage the H5HF_t struct */
+H5FL_DEFINE(H5HF_t);
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+/* Declare a free list to manage the H5HF_shared_t struct */
+H5FL_DEFINE_STATIC(H5HF_shared_t);
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_shared_init
+ *
+ * Purpose:	Allocate & initialize shared fractal heap info
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Feb 24 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5HF_shared_init(H5F_t *f, H5HF_t *fh, H5HF_type_t type)
+{
+    H5HF_shared_t *shared = NULL;       /* Shared fractal heap information */
+    herr_t ret_value = SUCCEED;           /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5HF_shared_init)
+
+    /* Allocate space for the shared information */
+    if(NULL == (shared = H5FL_CALLOC(H5HF_shared_t)))
+	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for fractal heap shared information")
+
+    /* Set the type of heap address mapping */
+    shared->type = type;
+
+    /* Make shared B-tree info reference counted */
+    if(NULL == (fh->shared = H5RC_create(shared, H5HF_shared_free)))
+	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "can't create ref-count wrapper for shared fractal heap info")
+
+done:
+    if(ret_value < 0)
+        if(shared)
+            H5HF_shared_free(shared);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF_shared_init() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_shared_free
+ *
+ * Purpose:	Free shared fractal heap info
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Feb 24 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5HF_shared_free(void *_shared)
+{
+    H5HF_shared_t *shared = (H5HF_shared_t *)_shared;
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI_NOINIT(H5HF_shared_free)
+
+    /* Sanity check */
+    HDassert(shared);
+
+    /* Free the shared info itself */
+    H5FL_FREE(H5HF_shared_t, shared);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF_shared_free() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_create
+ *
+ * Purpose:	Creates a new empty fractal heap in the file.
+ *
+ * Return:	Non-negative on success (with address of new fractal heap
+ *              filled in), negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Feb 24 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5HF_create(H5F_t *f, hid_t dxpl_id, H5HF_type_t type, haddr_t *addr_p)
+{
+    H5HF_t *fh = NULL;                  /* The new fractal heap header information */
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI(H5HF_create, FAIL)
+
+    /*
+     * Check arguments.
+     */
+    HDassert(f);
+    HDassert(addr_p);
+
+    /*
+     * Allocate file and memory data structures.
+     */
+    if(NULL == (fh = H5FL_MALLOC(H5HF_t)))
+	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for fractal heap header")
+
+    /* Assign internal information */
+    HDmemset(&fh->cache_info, 0, sizeof(H5AC_info_t));
+
+    /* Initialize shared fractal heap info */
+    if(H5HF_shared_init(f, fh, type) < 0)
+	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "can't create shared fractal heap info")
+
+    /* Allocate space for the header on disk */
+    if(HADDR_UNDEF == (*addr_p = H5MF_alloc(f, H5FD_MEM_FHEAP_HDR, dxpl_id, (hsize_t)H5HF_HEADER_SIZE(f))))
+	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap header")
+
+    /* Cache the new fractal heap node */
+    if(H5AC_set(f, dxpl_id, H5AC_FHEAP_HDR, *addr_p, fh, H5AC__NO_FLAGS_SET) < 0)
+	HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, FAIL, "can't add fractal heap header to cache")
+
+done:
+    if(ret_value < 0) {
+	if(fh)
+            (void)H5HF_cache_hdr_dest(f, fh);
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF_create() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_insert
+ *
+ * Purpose:	Insert a new object into a fractal heap.
+ *
+ * Return:	Non-negative on success (with heap ID of new object
+ *              filled in), negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Feb 24 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5HF_insert(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t size,
+    const void *obj, void *id/*out*/)
+{
+    H5HF_t *fh = NULL;                  /* The new fractal heap header information */
+    H5HF_shared_t *shared;              /* Shared fractal heap information */
+    unsigned hdr_flags = H5AC__NO_FLAGS_SET;    /* Metadata cache flags for header */
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI(H5HF_insert, FAIL)
+
+    /*
+     * Check arguments.
+     */
+    HDassert(f);
+    HDassert(H5F_addr_defined(addr));
+    HDassert(size > 0);
+    HDassert(obj);
+    HDassert(id);
+
+    /*
+     * Load the fractal heap header.
+     */
+    if(NULL == (fh = H5AC_protect(f, dxpl_id, H5AC_FHEAP_HDR, addr, NULL, NULL, H5AC_WRITE)))
+	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load fractal heap header")
+
+    /* Get the pointer to the shared fractal heap info */
+    shared = H5RC_GET_OBJ(fh->shared);
+    HDassert(shared);
+
+    /* Check if object is large enough to be standalone */
+    if(size >= shared->standalone_size) {
+    } /* end if */
+    else {
+    } /* end else */
+
+done:
+    if(fh && H5AC_unprotect(f, dxpl_id, H5AC_FHEAP_HDR, addr, fh, hdr_flags) < 0)
+        HDONE_ERROR(H5E_BTREE, H5E_PROTECT, FAIL, "unable to release fractal heap header")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF_insert() */
+
diff --git a/src/H5HFcache.c b/src/H5HFcache.c
new file mode 100644
index 0000000..9544242
--- /dev/null
+++ b/src/H5HFcache.c
@@ -0,0 +1,364 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:		H5HFcache.c
+ *			Feb 24 2006
+ *			Quincey Koziol <koziol@ncsa.uiuc.edu>
+ *
+ * Purpose:		Implement fractal heap metadata cache methods.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#define H5HF_PACKAGE		/*suppress error about including H5HFpkg  */
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5HFpkg.h"		/* Fractal heaps			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+
+/****************/
+/* Local Macros */
+/****************/
+
+/* Fractal heap format version #'s */
+#define H5HF_HDR_VERSION 0              /* Header */
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+/* Metadata cache callbacks */
+static H5HF_t *H5HF_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void *_type, void *udata);
+static herr_t H5HF_cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5HF_t *fh);
+static herr_t H5HF_cache_hdr_clear(H5F_t *f, H5HF_t *fh, hbool_t destroy);
+static herr_t H5HF_cache_hdr_size(const H5F_t *f, const H5HF_t *fh, size_t *size_ptr);
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+/* H5HF inherits cache-like properties from H5AC */
+const H5AC_class_t H5AC_FHEAP_HDR[1] = {{
+    H5AC_FHEAP_HDR_ID,
+    (H5AC_load_func_t)H5HF_cache_hdr_load,
+    (H5AC_flush_func_t)H5HF_cache_hdr_flush,
+    (H5AC_dest_func_t)H5HF_cache_hdr_dest,
+    (H5AC_clear_func_t)H5HF_cache_hdr_clear,
+    (H5AC_size_func_t)H5HF_cache_hdr_size,
+}};
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+/* Declare a free list to manage B-tree header data to/from disk */
+H5FL_BLK_DEFINE_STATIC(header_block);
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_cache_hdr_load
+ *
+ * Purpose:	Loads a fractal heap header from the disk.
+ *
+ * Return:	Success:	Pointer to a new fractal heap
+ *
+ *		Failure:	NULL
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Feb 24 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static H5HF_t *
+H5HF_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED *udata1, void UNUSED *udata2)
+{
+    H5HF_t		*fh = NULL;     /* Fractal heap info */
+    size_t		size;           /* Header size */
+    uint8_t		*buf = NULL;    /* Temporary buffer */
+    uint8_t		*p;             /* Pointer into raw data buffer */
+    H5HF_type_t         heap_type;      /* Type of heap */
+    uint32_t            metadata_chksum;        /* Metadata checksum value */
+    H5HF_t		*ret_value;     /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HF_cache_hdr_load, NULL)
+
+    /* Check arguments */
+    HDassert(f);
+    HDassert(H5F_addr_defined(addr));
+
+    /* Allocate space for the fractal heap data structure */
+    if(NULL == (fh = H5FL_MALLOC(H5HF_t)))
+	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+    HDmemset(&fh->cache_info, 0, sizeof(H5AC_info_t));
+
+    /* Compute the size of the fractal heap header on disk */
+    size = H5HF_HEADER_SIZE(f);
+
+    /* Allocate temporary buffer */
+    if((buf = H5FL_BLK_MALLOC(header_block, size)) == NULL)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+
+    /* Read header from disk */
+    if(H5F_block_read(f, H5FD_MEM_FHEAP_HDR, addr, size, dxpl_id, buf) < 0)
+	HGOTO_ERROR(H5E_HEAP, H5E_READERROR, NULL, "can't read fractal heap header")
+
+    p = buf;
+
+    /* magic number */
+    if(HDmemcmp(p, H5HF_HDR_MAGIC, H5HF_SIZEOF_MAGIC))
+	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "wrong fractal heap header signature")
+    p += H5HF_SIZEOF_MAGIC;
+
+    /* version */
+    if(*p++ != H5HF_HDR_VERSION)
+	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "wrong fractal heap header version")
+
+    /* Metadata flags (unused, currently) */
+/* XXX: Plan out metadata flags (including "read-only duplicate" feature) */
+    if(*p++ != 0)
+	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "unknown metadata flag in fractal heap header")
+
+    /* Metadata checksum (unused, currently) */
+    UINT32DECODE(p, metadata_chksum);
+/* XXX: Verify checksum */
+    if(metadata_chksum != 0)
+	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "incorrect metadata checksum for fractal heap header")
+
+    /* Fractal heap type */
+    heap_type = *p++;
+    HDassert(H5HF_ABSOLUTE == 0);
+    if(heap_type > H5HF_MAPPED)
+	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "incorrect fractal heap type")
+
+    /* Initialize shared fractal heap info */
+    if(H5HF_shared_init(f, fh, heap_type) < 0)
+	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "can't create shared fractal heap info")
+
+    /* Set return value */
+    ret_value = fh;
+
+done:
+    if(buf)
+        H5FL_BLK_FREE(header_block, buf);
+    if(!ret_value && fh)
+        (void)H5HF_cache_hdr_dest(f, fh);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF_cache_hdr_load() */ /*lint !e818 Can't make udata a pointer to const */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_cache_hdr_flush
+ *
+ * Purpose:	Flushes a dirty fractal heap header to disk.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Feb 24 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5HF_cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5HF_t *fh)
+{
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HF_cache_hdr_flush, FAIL)
+
+    /* check arguments */
+    HDassert(f);
+    HDassert(H5F_addr_defined(addr));
+    HDassert(fh);
+
+    if(fh->cache_info.is_dirty) {
+        H5HF_shared_t *shared;      /* Shared fractal heap information */
+        uint8_t	*buf = NULL;        /* Temporary raw data buffer */
+        uint8_t *p;                 /* Pointer into raw data buffer */
+        size_t	size;               /* Header size on disk */
+
+        /* Get the pointer to the shared B-tree info */
+        shared = H5RC_GET_OBJ(fh->shared);
+        HDassert(shared);
+
+        /* Compute the size of the B-tree header on disk */
+        size = H5HF_HEADER_SIZE(f);
+
+        /* Allocate temporary buffer */
+        if((buf = H5FL_BLK_MALLOC(header_block, size)) == NULL)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+        p = buf;
+
+        /* Magic number */
+        HDmemcpy(p, H5HF_HDR_MAGIC, H5HF_SIZEOF_MAGIC);
+        p += H5HF_SIZEOF_MAGIC;
+
+        /* Version # */
+        *p++ = H5HF_HDR_VERSION;
+
+        /* Metadata status flags */
+/* XXX: Set this? */
+        *p++ = 0;
+
+        /* Metadata checksum */
+/* XXX: Set this!  (After all the metadata is in the buffer) */
+        HDmemset(p, 0, 4);
+        p += 4;
+
+        /* Fractal heap type */
+        *p++ = shared->type;
+
+	/* Write the B-tree header. */
+        HDassert((size_t)(p - buf) == size);
+	if(H5F_block_write(f, H5FD_MEM_FHEAP_HDR, addr, size, dxpl_id, buf) < 0)
+	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFLUSH, FAIL, "unable to save fractal heap header to disk")
+
+        H5FL_BLK_FREE(header_block, buf);
+
+	fh->cache_info.is_dirty = FALSE;
+    } /* end if */
+
+    if(destroy)
+        if(H5HF_cache_hdr_dest(f, fh) < 0)
+	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap header")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5HF_cache_hdr_flush() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_cache_hdr_dest
+ *
+ * Purpose:	Destroys a fractal heap header in memory.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Feb 24 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+/* ARGSUSED */
+herr_t
+H5HF_cache_hdr_dest(H5F_t UNUSED *f, H5HF_t *fh)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5HF_cache_hdr_dest)
+
+    /*
+     * Check arguments.
+     */
+    HDassert(fh);
+
+    /* Decrement reference count on shared fractal heap info */
+    if(fh->shared)
+        H5RC_DEC(fh->shared);
+
+    /* Free fractal heap header info */
+    H5FL_FREE(H5HF_t, fh);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HF_cache_hdr_dest() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_cache_hdr_clear
+ *
+ * Purpose:	Mark a fractal heap header in memory as non-dirty.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Feb 24 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5HF_cache_hdr_clear(H5F_t *f, H5HF_t *fh, hbool_t destroy)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5HF_cache_hdr_clear)
+
+    /*
+     * Check arguments.
+     */
+    HDassert(fh);
+
+    /* Reset the dirty flag.  */
+    fh->cache_info.is_dirty = FALSE;
+
+    if(destroy)
+        if(H5HF_cache_hdr_dest(f, fh) < 0)
+	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap header")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF_cache_hdr_clear() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_cache_hdr_size
+ *
+ * Purpose:	Compute the size in bytes of a fractal heap header
+ *		on disk, and return it in *size_ptr.  On failure,
+ *		the value of *size_ptr is undefined.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Feb 24 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5HF_cache_hdr_size(const H5F_t *f, const H5HF_t UNUSED *fh, size_t *size_ptr)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5HF_cache_hdr_size)
+
+    /* check arguments */
+    HDassert(f);
+    HDassert(size_ptr);
+
+    /* Set size value */
+    *size_ptr = H5HF_HEADER_SIZE(f);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* H5HF_cache_hdr_size() */
+
diff --git a/src/H5HFdbg.c b/src/H5HFdbg.c
new file mode 100644
index 0000000..cb6476c
--- /dev/null
+++ b/src/H5HFdbg.c
@@ -0,0 +1,129 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:		H5HFdbg.c
+ *			Feb 24 2006
+ *			Quincey Koziol <koziol@ncsa.uiuc.edu>
+ *
+ * Purpose:		Dump debugging information about a fractal heap
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#define H5HF_PACKAGE		/*suppress error about including H5HFpkg  */
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5HFpkg.h"		/* Fractal heaps			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5FLprivate.h"	/* Free Lists                           */
+
+/****************/
+/* Local Macros */
+/****************/
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_hdr_debug
+ *
+ * Purpose:	Prints debugging info about a fractal heap header.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Feb 24 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5HF_hdr_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent, int fwidth)
+{
+    H5HF_t	*fh = NULL;             /* Fractal heap header info */
+    H5HF_shared_t *shared;              /* Shared fractal heap information */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI(H5HF_hdr_debug, FAIL)
+
+    /*
+     * Check arguments.
+     */
+    HDassert(f);
+    HDassert(H5F_addr_defined(addr));
+    HDassert(stream);
+    HDassert(indent >= 0);
+    HDassert(fwidth >= 0);
+
+    /*
+     * Load the fractal heap header.
+     */
+    if(NULL == (fh = H5AC_protect(f, dxpl_id, H5AC_FHEAP_HDR, addr, NULL, NULL, H5AC_READ)))
+	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load fractal heap header")
+
+    /* Get the pointer to the shared fractal heap info */
+    shared = H5RC_GET_OBJ(fh->shared);
+    HDassert(shared);
+
+    /* Print opening message */
+    HDfprintf(stream, "%*sFractal Heap Header...\n", indent, "");
+
+    /*
+     * Print the values.
+     */
+    HDfprintf(stream, "%*s%-*s %s\n", indent, "", fwidth,
+	      "Heap addressing method:",
+	      ((shared->type) == H5HF_ABSOLUTE ? "Absolute" :
+	      ((shared->type) == H5HF_MAPPED ? "Mapped" :
+              "Unknown!")));
+
+done:
+    if(fh && H5AC_unprotect(f, dxpl_id, H5AC_FHEAP_HDR, addr, fh, H5AC__NO_FLAGS_SET) < 0)
+        HDONE_ERROR(H5E_BTREE, H5E_PROTECT, FAIL, "unable to release fractal heap header")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF_hdr_debug() */
+
diff --git a/src/H5HFpkg.h b/src/H5HFpkg.h
new file mode 100644
index 0000000..d311aff
--- /dev/null
+++ b/src/H5HFpkg.h
@@ -0,0 +1,155 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Programmer:	Quincey Koziol <koziol@ncsa.uiuc.edu>
+ *		Friday, February 24, 2006
+ *
+ * Purpose:	This file contains declarations which are visible only within
+ *		the H5HF package.  Source files outside the H5HF package should
+ *		include H5HFprivate.h instead.
+ */
+#ifndef H5HF_PACKAGE
+#error "Do not include this file outside the H5HF package!"
+#endif
+
+#ifndef _H5HFpkg_H
+#define _H5HFpkg_H
+
+/* Get package's private header */
+#include "H5HFprivate.h"
+
+/* Other private headers needed by this file */
+#include "H5ACprivate.h"	/* Metadata cache			*/
+#include "H5FLprivate.h"	/* Free Lists                           */
+#include "H5RCprivate.h"	/* Reference counted object functions	*/
+
+/**************************/
+/* Package Private Macros */
+/**************************/
+
+/* Size of signature information (on disk) */
+#define H5HF_SIZEOF_MAGIC               4
+
+/* Fractal heap signatures */
+#define H5HF_HDR_MAGIC                  "FRHP"          /* Header */
+
+/* Size of the fractal heap header on disk */
+#define H5HF_HEADER_SIZE(f)     (                                             \
+    /* General metadata fields */                                             \
+    4   /* Signature */                                                       \
+    + 1 /* Version */                                                         \
+    + 1 /* Metadata flags */                                                  \
+    + 4 /* Metadata checksum */                                               \
+                                                                              \
+    /* Fractal heap header specific fields */                                 \
+    + 1 /* Heap type */                                                       \
+    )
+
+/****************************/
+/* Package Private Typedefs */
+/****************************/
+
+/* Doubling-table info */
+typedef struct H5HF_dtable_param_t {
+    /* Immutable, pre-set information for table */
+    unsigned    width;          /* Number of columns in the table (must be power of 2) */
+    hsize_t     start_block_size; /* Starting block size for table (must be power of 2) */
+    hsize_t     max_direct_size; /* Maximum size of a direct block (must be power of 2) */
+    hsize_t     max_index;      /* Maximum ID/offset for table (must be power of 2) */
+    unsigned    start_root_rows;        /* Starting number of rows for root indirect block */
+                                /* 0 indicates to create the full indirect block for the root,
+                                 * right from the start.  Doesn't have to be power of 2
+                                 */
+
+    /* Derived information that varies during lifetime of table */
+    haddr_t     table_addr;     /* Address of first block for table */
+                                /* Undefined if no space allocated for table */
+    unsigned    curr_root_rows; /* Current number of rows in the root indirect block */
+                                /* 0 indicates that the TABLE_ADDR field points
+                                 * to direct block (of START_BLOCK_SIZE) instead
+                                 * of indirect root block.
+                                 */
+} H5HF_dtable_param_t;
+
+/* Each fractal heap has certain information that can be shared across all
+ * the instances of blocks in that fractal heap.
+ */
+typedef struct H5HF_shared_t {
+    /* Shared internal information */
+    hsize_t     next_man_block; /* Offset of next direct managed block */
+    hsize_t     next_std_block; /* Offset of next direct standalone block */
+    hsize_t     total_man_free; /* Total amount of free space in managed blocks */
+    hsize_t     total_std_free; /* Total # of free standalone ID entries */
+
+    /* Doubling table information */
+    /* (Partially set by user, partially derived/updated internally) */
+    H5HF_dtable_param_t man_dtable_info;        /* Doubling-table info for managed objects */
+    H5HF_dtable_param_t std_dtable_info;        /* Doubling-table info for standalone objects */
+
+    /* Information set by user */
+    H5HF_type_t type;           /* Type of address mapping */
+    size_t standalone_size;     /* Size of object to store standalone */
+    size_t fixed_len_size;      /* Size of objects (only for heaps w/fixed-length objects) */
+
+    /* Information derived from user parameters */
+    hbool_t     fixed_len_obj;  /* Are objects in the heap fixed length? */
+    hbool_t     ref_count_obj;  /* Are objects in the heap ref. counted? */
+    hbool_t     have_io_filter; /* Does the heap have I/O filters for the direct blocks? */
+    hbool_t     write_once;     /* Is heap being written in "write once" mode? */
+} H5HF_shared_t;
+
+/* The fractal heap information */
+typedef struct H5HF_t {
+    /* Information for H5AC cache functions, _must_ be first field in structure */
+    H5AC_info_t cache_info;
+
+    /* Internal fractal heap information */
+    H5RC_t	*shared;	/* Ref-counted shared info	              */
+} H5HF_t;
+
+
+/*****************************/
+/* Package Private Variables */
+/*****************************/
+
+/* H5HF header inherits cache-like properties from H5AC */
+H5_DLLVAR const H5AC_class_t H5AC_FHEAP_HDR[1];
+
+/* Declare a free list to manage the H5HF_t struct */
+H5FL_EXTERN(H5HF_t);
+
+
+/******************************/
+/* Package Private Prototypes */
+/******************************/
+
+/* Routines for managing shared fractal heap info */
+H5_DLL herr_t H5HF_shared_init(H5F_t *f, H5HF_t *fh, H5HF_type_t type);
+
+/* Metadata cache callbacks */
+H5_DLL herr_t H5HF_cache_hdr_dest(H5F_t *f, H5HF_t *b);
+
+/* Debugging routines for dumping file structures */
+H5_DLL herr_t H5HF_hdr_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr,
+    FILE *stream, int indent, int fwidth);
+
+/* Testing routines */
+#ifdef H5HF_TESTING
+H5_DLL herr_t H5HF_get_addrmap_test(H5F_t *f, hid_t dxpl_id, haddr_t fh_addr,
+    H5HF_type_t *heap_type);
+#endif /* H5HF_TESTING */
+
+#endif /* _H5HFpkg_H */
+
diff --git a/src/H5HFprivate.h b/src/H5HFprivate.h
new file mode 100644
index 0000000..49c11c9
--- /dev/null
+++ b/src/H5HFprivate.h
@@ -0,0 +1,65 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:		H5HFprivate.h
+ *			Feb 24 2006
+ *			Quincey Koziol <koziol@ncsa.uiuc.edu>
+ *
+ * Purpose:		Private header for library accessible fractal heap routines.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef _H5HFprivate_H
+#define _H5HFprivate_H
+
+/* Include package's public header */
+#include "H5HFpublic.h"
+
+/* Private headers needed by this file */
+#include "H5Fprivate.h"		/* File access				*/
+
+/**************************/
+/* Library Private Macros */
+/**************************/
+
+
+/****************************/
+/* Library Private Typedefs */
+/****************************/
+
+/* Types of heaps */
+typedef enum {
+    H5HF_ABSOLUTE,      /* The heap uses absolute internal addressing */
+    H5HF_MAPPED         /* The heap maps internal addresses to allow compaction */
+} H5HF_type_t;
+
+
+/*****************************/
+/* Library-private Variables */
+/*****************************/
+ 
+/***************************************/
+/* Library-private Function Prototypes */
+/***************************************/
+H5_DLL herr_t H5HF_create(H5F_t *f, hid_t dxpl_id, H5HF_type_t type,
+    haddr_t *addr_p);
+H5_DLL herr_t H5HF_insert(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t size,
+    const void *obj, void *id/*out*/);
+
+#endif /* _H5HFprivate_H */
+
+
diff --git a/src/H5HFpublic.h b/src/H5HFpublic.h
new file mode 100644
index 0000000..70453dc
--- /dev/null
+++ b/src/H5HFpublic.h
@@ -0,0 +1,53 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:             H5HFpublic.h
+ *                      Feb 24 2006
+ *                      Quincey Koziol <koziol@ncsa.uiuc.edu>
+ *
+ * Purpose:             Public declarations for the fractal heap package.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef _H5HFpublic_H
+#define _H5HFpublic_H
+
+/* Public headers needed by this file */
+#include "H5public.h"
+
+/*****************/
+/* Public Macros */
+/*****************/
+
+/*******************/
+/* Public Typedefs */
+/*******************/
+
+/**********************************/
+/* Public API Function Prototypes */
+/**********************************/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _H5HFpublic_H */
+
diff --git a/src/H5HFtest.c b/src/H5HFtest.c
new file mode 100644
index 0000000..e9a3eeb
--- /dev/null
+++ b/src/H5HFtest.c
@@ -0,0 +1,112 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/* Programmer:  Quincey Koziol <koziol@ncsa.uiuc.edu>
+ *              Thursday, February  3, 2005
+ *
+ * Purpose:	Fractal heap testing functions.
+ */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#define H5HF_PACKAGE		/*suppress error about including H5HFpkg  */
+#define H5HF_TESTING		/*suppress warning about H5HF testing funcs*/
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5HFpkg.h"		/* Fractal heaps			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+
+/****************/
+/* Local Macros */
+/****************/
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_get_addrmap_test
+ *
+ * Purpose:	Retrieve the address mapping type
+ *
+ * Return:	Success:	non-negative
+ *
+ *		Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *              Friday, February 24, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5HF_get_addrmap_test(H5F_t *f, hid_t dxpl_id, haddr_t fh_addr, H5HF_type_t *heap_type)
+{
+    H5HF_t	*fh = NULL;             /* Pointer to the B-tree header */
+    H5HF_shared_t *shared;              /* Shared fractal heap information */
+    herr_t	ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5HF_get_addrmap_test)
+
+    /* Check arguments. */
+    HDassert(f);
+    HDassert(H5F_addr_defined(fh_addr));
+    HDassert(heap_type);
+
+    /* Look up the fractal heap header */
+    if(NULL == (fh = H5AC_protect(f, dxpl_id, H5AC_FHEAP_HDR, fh_addr, NULL, NULL, H5AC_READ)))
+	HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load fractal heap header")
+
+    /* Get the pointer to the shared fractal heap info */
+    shared = H5RC_GET_OBJ(fh->shared);
+    HDassert(shared);
+
+    /* Get fractal heap address mapping */
+    *heap_type = shared->type;
+
+done:
+    /* Release fractal heap header node */
+    if(fh && H5AC_unprotect(f, dxpl_id, H5AC_FHEAP_HDR, fh_addr, fh, H5AC__NO_FLAGS_SET) < 0)
+        HDONE_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, FAIL, "unable to release fractal heap header info")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5HF_get_addrmap_test() */
+
diff --git a/src/H5err.txt b/src/H5err.txt
index 65c4e1f..88eb01c 100644
--- a/src/H5err.txt
+++ b/src/H5err.txt
@@ -71,7 +71,6 @@ MAJOR, H5E_TST, Ternary Search Trees
 MAJOR, H5E_RS, Reference Counted Strings
 MAJOR, H5E_ERROR, Error API
 MAJOR, H5E_SLIST, Skip Lists
-MAJOR, H5E_BLKTRK, Block tracker
 
 # Sections (for grouping minor errors)
 SECTION, ARGS, Argument errors
@@ -91,7 +90,6 @@ SECTION, MPI, Parallel MPI errors
 SECTION, HEAP, Heap errors
 SECTION, FPH5, FPHDF5 errors
 SECTION, PIPELINE, I/O pipeline errors
-SECTION, BLKTRK, Block tracker errors
 SECTION, SYSTEM, System level errors
 
 # Minor errors
@@ -223,8 +221,5 @@ MINOR, PIPELINE, H5E_CANAPPLY, Error from filter 'can apply' callback
 MINOR, PIPELINE, H5E_SETLOCAL, Error from filter 'set local' callback
 MINOR, PIPELINE, H5E_NOENCODER, Filter present but encoding disabled
 
-# Block tracker errors
-MINOR, BLKTRK, H5E_OVERLAPS, Blocks overlap
-
 # System level errors
 MINOR, SYSTEM, H5E_SYSERRSTR, System error message
diff --git a/src/Makefile.am b/src/Makefile.am
index d8c82d0..dc3629a 100755
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -55,6 +55,7 @@ libhdf5_la_SOURCES= H5.c H5A.c H5AC.c H5B.c H5Bcache.c H5B2.c H5B2cache.c \
         H5Gstab.c  \
         H5Gtest.c  \
         H5Gtraverse.c  \
+        H5HF.c H5HFcache.c H5HFdbg.c H5HFtest.c \
         H5HG.c H5HGdbg.c H5HL.c H5HLdbg.c H5HP.c H5I.c H5MF.c H5MM.c \
         H5MP.c H5MPtest.c \
         H5O.c \
@@ -83,7 +84,7 @@ include_HEADERS =H5public.h H5Apublic.h H5ACpublic.h H5Bpublic.h H5B2public.h \
         H5Epubgen.h H5Epublic.h H5Fpublic.h H5FDpublic.h H5FDcore.h H5FDfamily.h          \
         H5FDfphdf5.h H5FDlog.h H5FDmpi.h H5FDmpio.h H5FDmpiposix.h              \
         H5FDmulti.h H5FDsec2.h  H5FDstdio.h H5FDstream.h H5FPpublic.h             \
-        H5Gpublic.h H5HGpublic.h H5HLpublic.h H5Ipublic.h                     \
+        H5Gpublic.h H5HFpublic.h H5HGpublic.h H5HLpublic.h H5Ipublic.h \
         H5MMpublic.h H5Opublic.h H5Ppublic.h H5Rpublic.h H5Spublic.h \
         H5Tpublic.h H5Zpublic.h H5pubconf.h hdf5.h H5api_adpt.h
 
diff --git a/src/Makefile.in b/src/Makefile.in
index 7a58aa4..1b5ea41 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -92,21 +92,22 @@ am_libhdf5_la_OBJECTS = H5.lo H5A.lo H5AC.lo H5B.lo H5Bcache.lo \
 	H5FDstdio.lo H5FDstream.lo H5FL.lo H5FO.lo H5FP.lo \
 	H5FPclient.lo H5FPserver.lo H5FS.lo H5G.lo H5Gent.lo \
 	H5Glink.lo H5Gloc.lo H5Gname.lo H5Gnode.lo H5Gobj.lo H5Goh.lo \
-	H5Gstab.lo H5Gtest.lo H5Gtraverse.lo H5HG.lo H5HGdbg.lo \
-	H5HL.lo H5HLdbg.lo H5HP.lo H5I.lo H5MF.lo H5MM.lo H5MP.lo \
-	H5MPtest.lo H5O.lo H5Oattr.lo H5Obogus.lo H5Ocache.lo \
-	H5Ocont.lo H5Odtype.lo H5Oefl.lo H5Ofill.lo H5Oginfo.lo \
-	H5Olayout.lo H5Olinfo.lo H5Olink.lo H5Omtime.lo H5Oname.lo \
-	H5Onull.lo H5Opline.lo H5Osdspace.lo H5Oshared.lo H5Ostab.lo \
-	H5P.lo H5Pacpl.lo H5Pdcpl.lo H5Pdxpl.lo H5Pfapl.lo H5Pfcpl.lo \
-	H5Pgcpl.lo H5Pocpl.lo H5Ptest.lo H5R.lo H5RC.lo H5RS.lo H5S.lo \
-	H5Sall.lo H5Shyper.lo H5Smpio.lo H5Snone.lo H5Spoint.lo \
-	H5Sselect.lo H5Stest.lo H5SL.lo H5ST.lo H5T.lo H5Tarray.lo \
-	H5Tbit.lo H5Tcommit.lo H5Tcompound.lo H5Tconv.lo H5Tcset.lo \
-	H5Tenum.lo H5Tfields.lo H5Tfixed.lo H5Tfloat.lo H5Tinit.lo \
-	H5Tnative.lo H5Toffset.lo H5Toh.lo H5Topaque.lo H5Torder.lo \
-	H5Tpad.lo H5Tprecis.lo H5Tstrpad.lo H5Tvlen.lo H5TS.lo H5V.lo \
-	H5Z.lo H5Zdeflate.lo H5Zfletcher32.lo H5Znbit.lo H5Zshuffle.lo \
+	H5Gstab.lo H5Gtest.lo H5Gtraverse.lo H5HF.lo H5HFcache.lo \
+	H5HFdbg.lo H5HFtest.lo H5HG.lo H5HGdbg.lo H5HL.lo H5HLdbg.lo \
+	H5HP.lo H5I.lo H5MF.lo H5MM.lo H5MP.lo H5MPtest.lo H5O.lo \
+	H5Oattr.lo H5Obogus.lo H5Ocache.lo H5Ocont.lo H5Odtype.lo \
+	H5Oefl.lo H5Ofill.lo H5Oginfo.lo H5Olayout.lo H5Olinfo.lo \
+	H5Olink.lo H5Omtime.lo H5Oname.lo H5Onull.lo H5Opline.lo \
+	H5Osdspace.lo H5Oshared.lo H5Ostab.lo H5P.lo H5Pacpl.lo \
+	H5Pdcpl.lo H5Pdxpl.lo H5Pfapl.lo H5Pfcpl.lo H5Pgcpl.lo \
+	H5Pocpl.lo H5Ptest.lo H5R.lo H5RC.lo H5RS.lo H5S.lo H5Sall.lo \
+	H5Shyper.lo H5Smpio.lo H5Snone.lo H5Spoint.lo H5Sselect.lo \
+	H5Stest.lo H5SL.lo H5ST.lo H5T.lo H5Tarray.lo H5Tbit.lo \
+	H5Tcommit.lo H5Tcompound.lo H5Tconv.lo H5Tcset.lo H5Tenum.lo \
+	H5Tfields.lo H5Tfixed.lo H5Tfloat.lo H5Tinit.lo H5Tnative.lo \
+	H5Toffset.lo H5Toh.lo H5Topaque.lo H5Torder.lo H5Tpad.lo \
+	H5Tprecis.lo H5Tstrpad.lo H5Tvlen.lo H5TS.lo H5V.lo H5Z.lo \
+	H5Zdeflate.lo H5Zfletcher32.lo H5Znbit.lo H5Zshuffle.lo \
 	H5Zszip.lo H5Zscaleoffset.lo H5Ztrans.lo
 libhdf5_la_OBJECTS = $(am_libhdf5_la_OBJECTS)
 PROGRAMS = $(noinst_PROGRAMS)
@@ -406,6 +407,7 @@ libhdf5_la_SOURCES = H5.c H5A.c H5AC.c H5B.c H5Bcache.c H5B2.c H5B2cache.c \
         H5Gstab.c  \
         H5Gtest.c  \
         H5Gtraverse.c  \
+        H5HF.c H5HFcache.c H5HFdbg.c H5HFtest.c \
         H5HG.c H5HGdbg.c H5HL.c H5HLdbg.c H5HP.c H5I.c H5MF.c H5MM.c \
         H5MP.c H5MPtest.c \
         H5O.c \
@@ -434,7 +436,7 @@ include_HEADERS = H5public.h H5Apublic.h H5ACpublic.h H5Bpublic.h H5B2public.h \
         H5Epubgen.h H5Epublic.h H5Fpublic.h H5FDpublic.h H5FDcore.h H5FDfamily.h          \
         H5FDfphdf5.h H5FDlog.h H5FDmpi.h H5FDmpio.h H5FDmpiposix.h              \
         H5FDmulti.h H5FDsec2.h  H5FDstdio.h H5FDstream.h H5FPpublic.h             \
-        H5Gpublic.h H5HGpublic.h H5HLpublic.h H5Ipublic.h                     \
+        H5Gpublic.h H5HFpublic.h H5HGpublic.h H5HLpublic.h H5Ipublic.h \
         H5MMpublic.h H5Opublic.h H5Ppublic.h H5Rpublic.h H5Spublic.h \
         H5Tpublic.h H5Zpublic.h H5pubconf.h hdf5.h H5api_adpt.h
 
@@ -613,6 +615,10 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Gstab.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Gtest.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Gtraverse.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5HF.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5HFcache.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5HFdbg.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5HFtest.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5HG.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5HGdbg.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5HL.Plo@am__quote@
diff --git a/test/Makefile.am b/test/Makefile.am
index 8e22514..c924995 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -32,7 +32,7 @@ SCRIPT_DEPEND = error_test$(EXEEXT) err_compat$(EXEEXT)
 # executed, generally most specific tests to least specific tests.
 # As an exception, long-running tests should occur earlier in the list.
 # This gives them more time to run when tests are executing in parallel.
-TEST_PROG=testhdf5 lheap ohdr stab gheap btree2 cache cache_api \
+TEST_PROG=testhdf5 lheap fheap ohdr stab gheap btree2 cache cache_api \
            pool hyperslab istore bittests dt_arith \
            dtypes dsets cmpd_dset extend external objcopy links unlink big mtime     \
            fillval mount flush1 flush2 enum \
@@ -94,7 +94,7 @@ flush2.chkexe_: flush1.chkexe_
 # prefix or low-level driver with environment variables will influence 
 # the temporary file name in ways that the makefile is not aware of.
 CHECK_CLEANFILES+=cmpd_dset.h5 compact_dataset.h5 dataset.h5 extend.h5 istore.h5\
-            tfile[1-4].h5 th5s[1-3].h5 lheap.h5 ohdr.h5 stab[1-2].h5 \
+            tfile[1-4].h5 th5s[1-3].h5 lheap.h5 fheap.h5 ohdr.h5 stab[1-2].h5 \
             extern_[1-3].h5 extern_[1-4][ab].raw gheap[0-4].h5 dt_arith[1-2]\
             links.h5 links[1-3].h5 big.data big[0-9][0-9][0-9][0-9][0-9].h5  \
             dtypes[1-8].h5 dt_arith[1-2].h5 tattr.h5 tselect.h5 mtime.h5 \
diff --git a/test/Makefile.in b/test/Makefile.in
index 2be16e9..7be578d 100644
--- a/test/Makefile.in
+++ b/test/Makefile.in
@@ -31,7 +31,7 @@
 #
 
 
-SOURCES = $(libh5test_la_SOURCES) big.c bittests.c btree2.c cache.c cache_api.c cmpd_dset.c dangle.c dsets.c dt_arith.c dtransform.c dtypes.c enum.c err_compat.c error_test.c extend.c external.c fillval.c flush1.c flush2.c gen_deflate.c gen_filters.c gen_new_array.c gen_new_fill.c gen_new_group.c gen_new_mtime.c gen_new_super.c gen_noencoder.c gen_nullspace.c getname.c gheap.c hyperslab.c istore.c lheap.c links.c mount.c mtime.c ntypes.c objcopy.c ohdr.c pool.c reserved.c set_extent.c space_overflow.c stab.c stream_test.c $(testhdf5_SOURCES) testmeta.c $(ttsafe_SOURCES) unlink.c vfd.c
+SOURCES = $(libh5test_la_SOURCES) big.c bittests.c btree2.c cache.c cache_api.c cmpd_dset.c dangle.c dsets.c dt_arith.c dtransform.c dtypes.c enum.c err_compat.c error_test.c extend.c external.c fheap.c fillval.c flush1.c flush2.c gen_deflate.c gen_filters.c gen_new_array.c gen_new_fill.c gen_new_group.c gen_new_mtime.c gen_new_super.c gen_noencoder.c gen_nullspace.c getname.c gheap.c hyperslab.c istore.c lheap.c links.c mount.c mtime.c ntypes.c objcopy.c ohdr.c pool.c reserved.c set_extent.c space_overflow.c stab.c stream_test.c $(testhdf5_SOURCES) testmeta.c $(ttsafe_SOURCES) unlink.c vfd.c
 
 srcdir = @srcdir@
 top_srcdir = @top_srcdir@
@@ -73,14 +73,14 @@ LTLIBRARIES = $(noinst_LTLIBRARIES)
 libh5test_la_LIBADD =
 am_libh5test_la_OBJECTS = h5test.lo testframe.lo cache_common.lo
 libh5test_la_OBJECTS = $(am_libh5test_la_OBJECTS)
-am__EXEEXT_1 = testhdf5$(EXEEXT) lheap$(EXEEXT) ohdr$(EXEEXT) \
-	stab$(EXEEXT) gheap$(EXEEXT) btree2$(EXEEXT) cache$(EXEEXT) \
-	cache_api$(EXEEXT) pool$(EXEEXT) hyperslab$(EXEEXT) \
-	istore$(EXEEXT) bittests$(EXEEXT) dt_arith$(EXEEXT) \
-	dtypes$(EXEEXT) dsets$(EXEEXT) cmpd_dset$(EXEEXT) \
-	extend$(EXEEXT) external$(EXEEXT) objcopy$(EXEEXT) \
-	links$(EXEEXT) unlink$(EXEEXT) big$(EXEEXT) mtime$(EXEEXT) \
-	fillval$(EXEEXT) mount$(EXEEXT) flush1$(EXEEXT) \
+am__EXEEXT_1 = testhdf5$(EXEEXT) lheap$(EXEEXT) fheap$(EXEEXT) \
+	ohdr$(EXEEXT) stab$(EXEEXT) gheap$(EXEEXT) btree2$(EXEEXT) \
+	cache$(EXEEXT) cache_api$(EXEEXT) pool$(EXEEXT) \
+	hyperslab$(EXEEXT) istore$(EXEEXT) bittests$(EXEEXT) \
+	dt_arith$(EXEEXT) dtypes$(EXEEXT) dsets$(EXEEXT) \
+	cmpd_dset$(EXEEXT) extend$(EXEEXT) external$(EXEEXT) \
+	objcopy$(EXEEXT) links$(EXEEXT) unlink$(EXEEXT) big$(EXEEXT) \
+	mtime$(EXEEXT) fillval$(EXEEXT) mount$(EXEEXT) flush1$(EXEEXT) \
 	flush2$(EXEEXT) enum$(EXEEXT) set_extent$(EXEEXT) \
 	ttsafe$(EXEEXT) stream_test$(EXEEXT) getname$(EXEEXT) \
 	vfd$(EXEEXT) ntypes$(EXEEXT) dangle$(EXEEXT) \
@@ -161,6 +161,10 @@ external_SOURCES = external.c
 external_OBJECTS = external.$(OBJEXT)
 external_LDADD = $(LDADD)
 external_DEPENDENCIES = libh5test.la $(am__DEPENDENCIES_1)
+fheap_SOURCES = fheap.c
+fheap_OBJECTS = fheap.$(OBJEXT)
+fheap_LDADD = $(LDADD)
+fheap_DEPENDENCIES = libh5test.la $(am__DEPENDENCIES_1)
 fillval_SOURCES = fillval.c
 fillval_OBJECTS = fillval.$(OBJEXT)
 fillval_LDADD = $(LDADD)
@@ -320,25 +324,25 @@ LINK = $(LIBTOOL) --tag=CC --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
 SOURCES = $(libh5test_la_SOURCES) big.c bittests.c btree2.c cache.c \
 	cache_api.c cmpd_dset.c dangle.c dsets.c dt_arith.c \
 	dtransform.c dtypes.c enum.c err_compat.c error_test.c \
-	extend.c external.c fillval.c flush1.c flush2.c gen_deflate.c \
-	gen_filters.c gen_new_array.c gen_new_fill.c gen_new_group.c \
-	gen_new_mtime.c gen_new_super.c gen_noencoder.c \
-	gen_nullspace.c getname.c gheap.c hyperslab.c istore.c lheap.c \
-	links.c mount.c mtime.c ntypes.c objcopy.c ohdr.c pool.c \
-	reserved.c set_extent.c space_overflow.c stab.c stream_test.c \
-	$(testhdf5_SOURCES) testmeta.c $(ttsafe_SOURCES) unlink.c \
-	vfd.c
+	extend.c external.c fheap.c fillval.c flush1.c flush2.c \
+	gen_deflate.c gen_filters.c gen_new_array.c gen_new_fill.c \
+	gen_new_group.c gen_new_mtime.c gen_new_super.c \
+	gen_noencoder.c gen_nullspace.c getname.c gheap.c hyperslab.c \
+	istore.c lheap.c links.c mount.c mtime.c ntypes.c objcopy.c \
+	ohdr.c pool.c reserved.c set_extent.c space_overflow.c stab.c \
+	stream_test.c $(testhdf5_SOURCES) testmeta.c $(ttsafe_SOURCES) \
+	unlink.c vfd.c
 DIST_SOURCES = $(libh5test_la_SOURCES) big.c bittests.c btree2.c \
 	cache.c cache_api.c cmpd_dset.c dangle.c dsets.c dt_arith.c \
 	dtransform.c dtypes.c enum.c err_compat.c error_test.c \
-	extend.c external.c fillval.c flush1.c flush2.c gen_deflate.c \
-	gen_filters.c gen_new_array.c gen_new_fill.c gen_new_group.c \
-	gen_new_mtime.c gen_new_super.c gen_noencoder.c \
-	gen_nullspace.c getname.c gheap.c hyperslab.c istore.c lheap.c \
-	links.c mount.c mtime.c ntypes.c objcopy.c ohdr.c pool.c \
-	reserved.c set_extent.c space_overflow.c stab.c stream_test.c \
-	$(testhdf5_SOURCES) testmeta.c $(ttsafe_SOURCES) unlink.c \
-	vfd.c
+	extend.c external.c fheap.c fillval.c flush1.c flush2.c \
+	gen_deflate.c gen_filters.c gen_new_array.c gen_new_fill.c \
+	gen_new_group.c gen_new_mtime.c gen_new_super.c \
+	gen_noencoder.c gen_nullspace.c getname.c gheap.c hyperslab.c \
+	istore.c lheap.c links.c mount.c mtime.c ntypes.c objcopy.c \
+	ohdr.c pool.c reserved.c set_extent.c space_overflow.c stab.c \
+	stream_test.c $(testhdf5_SOURCES) testmeta.c $(ttsafe_SOURCES) \
+	unlink.c vfd.c
 ETAGS = etags
 CTAGS = ctags
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
@@ -586,9 +590,9 @@ TRACE = perl $(top_srcdir)/bin/trace
 # the temporary file name in ways that the makefile is not aware of.
 CHECK_CLEANFILES = *.chkexe *.chklog *.clog cmpd_dset.h5 \
 	compact_dataset.h5 dataset.h5 extend.h5 istore.h5 \
-	tfile[1-4].h5 th5s[1-3].h5 lheap.h5 ohdr.h5 stab[1-2].h5 \
-	extern_[1-3].h5 extern_[1-4][ab].raw gheap[0-4].h5 \
-	dt_arith[1-2] links.h5 links[1-3].h5 big.data \
+	tfile[1-4].h5 th5s[1-3].h5 lheap.h5 fheap.h5 ohdr.h5 \
+	stab[1-2].h5 extern_[1-3].h5 extern_[1-4][ab].raw \
+	gheap[0-4].h5 dt_arith[1-2] links.h5 links[1-3].h5 big.data \
 	big[0-9][0-9][0-9][0-9][0-9].h5 dtypes[1-8].h5 \
 	dt_arith[1-2].h5 tattr.h5 tselect.h5 mtime.h5 unlink.h5 \
 	unicode.h5 fillval_[0-9].h5 fillval.raw mount_[0-9].h5 \
@@ -612,7 +616,7 @@ SCRIPT_DEPEND = error_test$(EXEEXT) err_compat$(EXEEXT)
 # executed, generally most specific tests to least specific tests.
 # As an exception, long-running tests should occur earlier in the list.
 # This gives them more time to run when tests are executing in parallel.
-TEST_PROG = testhdf5 lheap ohdr stab gheap btree2 cache cache_api \
+TEST_PROG = testhdf5 lheap fheap ohdr stab gheap btree2 cache cache_api \
            pool hyperslab istore bittests dt_arith \
            dtypes dsets cmpd_dset extend external objcopy links unlink big mtime     \
            fillval mount flush1 flush2 enum \
@@ -773,6 +777,9 @@ extend$(EXEEXT): $(extend_OBJECTS) $(extend_DEPENDENCIES)
 external$(EXEEXT): $(external_OBJECTS) $(external_DEPENDENCIES) 
 	@rm -f external$(EXEEXT)
 	$(LINK) $(external_LDFLAGS) $(external_OBJECTS) $(external_LDADD) $(LIBS)
+fheap$(EXEEXT): $(fheap_OBJECTS) $(fheap_DEPENDENCIES) 
+	@rm -f fheap$(EXEEXT)
+	$(LINK) $(fheap_LDFLAGS) $(fheap_OBJECTS) $(fheap_LDADD) $(LIBS)
 fillval$(EXEEXT): $(fillval_OBJECTS) $(fillval_DEPENDENCIES) 
 	@rm -f fillval$(EXEEXT)
 	$(LINK) $(fillval_LDFLAGS) $(fillval_OBJECTS) $(fillval_LDADD) $(LIBS)
@@ -899,6 +906,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/error_test.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/extend.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/external.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/fheap.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/fillval.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/flush1.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/flush2.Po@am__quote@
diff --git a/test/fheap.c b/test/fheap.c
new file mode 100644
index 0000000..b1fce69
--- /dev/null
+++ b/test/fheap.c
@@ -0,0 +1,251 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/* Programmer:  Quincey Koziol <koziol@ncsa.uiuc.edu>
+ *              Friday, February 24, 2006
+ */
+#include "h5test.h"
+
+/*
+ * This file needs to access private datatypes from the H5HF package.
+ * This file also needs to access the fractal heap testing code.
+ */
+#define H5HF_PACKAGE
+#define H5HF_TESTING
+#include "H5HFpkg.h"
+
+/* Other private headers that this test requires */
+#include "H5Iprivate.h"
+
+const char *FILENAME[] = {
+    "fheap",
+    NULL
+};
+
+
+/*-------------------------------------------------------------------------
+ * Function:	test_create
+ *
+ * Purpose:	Create fractal heap
+ *
+ * Return:	Success:	0
+ *
+ *		Failure:	1
+ *
+ * Programmer:	Quincey Koziol
+ *              Friday, February 24, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+test_create(hid_t fapl)
+{
+    hid_t	file = -1;              /* File ID */
+    char	filename[1024];         /* Filename to use */
+    H5F_t	*f = NULL;              /* Internal file object pointer */
+    H5HF_type_t heap_type, test_heap_type; /* Type of address mapping for fractal heap */
+    haddr_t     fh_addr;                /* Address of fractal heap created */
+
+    /* Set the filename to use for this test (dependent on fapl) */
+    h5_fixname(FILENAME[0], fapl, filename, sizeof(filename));
+
+    /* Create the file to work on */
+    if((file = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+        TEST_ERROR
+
+    /* Get a pointer to the internal file object */
+    if(NULL == (f = H5I_object(file)))
+        STACK_ERROR
+
+    /*
+     * Test fractal heap creation (w/absolute address mapping)
+     */
+    TESTING("Fractal heap creation (w/absolute address mapping)");
+    heap_type = H5HF_ABSOLUTE;
+    if(H5HF_create(f, H5P_DATASET_XFER_DEFAULT, heap_type, &fh_addr/*out*/) < 0)
+        FAIL_STACK_ERROR
+    if(!H5F_addr_defined(fh_addr))
+        FAIL_STACK_ERROR
+    PASSED()
+
+    /* Query the type of address mapping */
+    TESTING("Query absolute address mapping setting");
+    test_heap_type = H5HF_MAPPED;
+    if(H5HF_get_addrmap_test(f, H5P_DATASET_XFER_DEFAULT, fh_addr, &test_heap_type) < 0)
+        FAIL_STACK_ERROR
+    if(test_heap_type != heap_type)
+        FAIL_STACK_ERROR
+    PASSED()
+
+    /*
+     * Test fractal heap creation (w/mapped address mapping)
+     */
+    TESTING("Fractal heap creation (w/mapped address mapping)");
+    heap_type = H5HF_MAPPED;
+    if(H5HF_create(f, H5P_DATASET_XFER_DEFAULT, heap_type, &fh_addr/*out*/) < 0)
+        FAIL_STACK_ERROR
+    if(!H5F_addr_defined(fh_addr))
+        FAIL_STACK_ERROR
+    PASSED()
+
+    /* Query the type of address mapping */
+    TESTING("Query mapped address mapping setting");
+    test_heap_type = H5HF_ABSOLUTE;
+    if(H5HF_get_addrmap_test(f, H5P_DATASET_XFER_DEFAULT, fh_addr, &test_heap_type) < 0)
+        FAIL_STACK_ERROR
+    if(test_heap_type != heap_type)
+        FAIL_STACK_ERROR
+    PASSED()
+
+    /* Close the file */
+    if(H5Fclose(file) < 0)
+        TEST_ERROR
+
+    /* All tests passed */
+    return(0);
+
+error:
+    H5E_BEGIN_TRY {
+	H5Fclose(file);
+    } H5E_END_TRY;
+    return(1);
+} /* test_create() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	test_abs_insert_first
+ *
+ * Purpose:	Test inserting first object into absolute heap
+ *
+ * Return:	Success:	0
+ *
+ *		Failure:	1
+ *
+ * Programmer:	Quincey Koziol
+ *              Friday, February 24, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+test_abs_insert_first(hid_t fapl)
+{
+    hid_t	file = -1;              /* File ID */
+    hid_t       dxpl = H5P_DATASET_XFER_DEFAULT;     /* DXPL to use */
+    char	filename[1024];         /* Filename to use */
+    H5F_t	*f = NULL;              /* Internal file object pointer */
+    haddr_t     fh_addr;                /* Address of fractal heap created */
+    unsigned char obj[10];              /* Buffer for object to insert */
+    haddr_t     heap_id;                /* Heap ID for object inserted */
+    unsigned    u;                      /* Local index variable */
+    herr_t      ret;                    /* Generic error return value */
+
+    /* Set the filename to use for this test (dependent on fapl) */
+    h5_fixname(FILENAME[0], fapl, filename, sizeof(filename));
+
+    /* Create the file to work on */
+    if((file = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+        TEST_ERROR
+
+    /* Get a pointer to the internal file object */
+    if(NULL == (f = H5I_object(file)))
+        STACK_ERROR
+
+    /* Create absolute heap */
+    if(H5HF_create(f, dxpl, H5HF_ABSOLUTE, &fh_addr/*out*/) < 0)
+        FAIL_STACK_ERROR
+    if(!H5F_addr_defined(fh_addr))
+        FAIL_STACK_ERROR
+#ifdef QAK
+HDfprintf(stdout, "Fractal heap header address = %a\n", fh_addr);
+#endif /* QAK */
+
+    /* Initialize object buffer */
+    for(u = 0; u < sizeof(obj); u++)
+        obj[u] = u;
+
+    /*
+     * Test inserting first (small) object into absolute heap
+     */
+    TESTING("Inserting first (small) object into absolute heap");
+    heap_id = HADDR_UNDEF;
+    if(H5HF_insert(f, dxpl, fh_addr, sizeof(obj), obj, &heap_id) < 0)
+        FAIL_STACK_ERROR
+#ifdef QAK
+HDfprintf(stdout, "heap_id = %a\n", heap_id);
+#endif /* QAK */
+    PASSED()
+
+    /* Close the file */
+    if(H5Fclose(file) < 0)
+        TEST_ERROR
+
+    /* All tests passed */
+    return(0);
+
+error:
+    H5E_BEGIN_TRY {
+	H5Fclose(file);
+    } H5E_END_TRY;
+    return(1);
+} /* test_abs_insert_first() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	main
+ *
+ * Purpose:	Test the fractal heap code
+ *
+ * Return:	Success:
+ *
+ *		Failure:
+ *
+ * Programmer:	Quincey Koziol
+ *              Friday, February 24, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+main(void)
+{
+    hid_t	fapl = -1;              /* File access property list for data files */
+    unsigned	nerrors = 0;            /* Cumulative error count */
+
+    /* Reset library */
+    h5_reset();
+    fapl = h5_fileaccess();
+
+    /* Test fractal heap creation */
+    nerrors += test_create(fapl);
+
+    /* Test fractal heap object insertion */
+    nerrors += test_abs_insert_first(fapl);
+
+    if(nerrors)
+        goto error;
+    puts("All fractal heap tests passed.");
+#ifndef QAK
+    h5_cleanup(FILENAME, fapl);
+#else /* QAK */
+HDfprintf(stderr, "Uncomment cleanup!\n");
+#endif /* QAK */
+    return 0;
+
+error:
+    puts("*** TESTS FAILED ***");
+    H5E_BEGIN_TRY {
+	H5Pclose(fapl);
+    } H5E_END_TRY;
+    return 1;
+}
+
diff --git a/tools/misc/h5debug.c b/tools/misc/h5debug.c
index 0228d98..b93ec2a 100644
--- a/tools/misc/h5debug.c
+++ b/tools/misc/h5debug.c
@@ -28,25 +28,28 @@
 #define H5O_PACKAGE		/*suppress error about including H5Opkg	  */
 #define H5B2_PACKAGE		/*suppress error about including H5B2pkg  */
 #define H5B2_TESTING		/*suppress warning about H5B2 testing funcs*/
+#define H5HF_PACKAGE		/*suppress error about including H5HFpkg  */
 
 #include "H5private.h"		/* Generic Functions			*/
-#include "H5Bprivate.h"
-#include "H5B2pkg.h"		/* B-trees				*/
-#include "H5Dprivate.h"
+#include "H5Bprivate.h"		/* B-trees				*/
+#include "H5B2pkg.h"		/* v2 B-trees				*/
+#include "H5Dprivate.h"		/* Datasets				*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
-#include "H5Fpkg.h"
-#include "H5Gprivate.h"
-#include "H5HGprivate.h"
-#include "H5HLprivate.h"
-#include "H5Iprivate.h"
-#include "H5Opkg.h"
-#include "H5Pprivate.h"
+#include "H5Fpkg.h"             /* File access				*/
+#include "H5Gprivate.h"		/* Groups				*/
+#include "H5HFpkg.h"		/* Fractal heaps			*/
+#include "H5HGprivate.h"	/* Global Heaps				*/
+#include "H5HLprivate.h"	/* Local Heaps				*/
+#include "H5Iprivate.h"		/* IDs			  		*/
+#include "H5Opkg.h"             /* Object headers			*/
+#include "H5Pprivate.h"		/* Property lists			*/
 
 /* File drivers */
 #include "H5FDfamily.h"
 
 #define INDENT  3
 #define VCOL    50
+#define SIGLEN  H5F_SIGNATURE_LEN       /* Size of signature buffer */
 
 
 /*-------------------------------------------------------------------------
@@ -72,7 +75,7 @@ main(int argc, char *argv[])
     hid_t	fid, fapl, dxpl;
     H5F_t       *f;
     haddr_t     addr=0, extra=0, extra2=0;
-    uint8_t     sig[16];
+    uint8_t     sig[SIGLEN];
     int         i;
     herr_t      status = SUCCEED;
 
@@ -114,16 +117,13 @@ main(int argc, char *argv[])
     /*
      * Parse command arguments.
      */
-    if (argc > 2) {
-/*        printf("New address: %s\n", argv[2]); */
+    if (argc > 2)
         addr = HDstrtoll(argv[2], NULL, 0);
-    }
-    if (argc > 3) {
+    if (argc > 3)
         extra = HDstrtoll(argv[3], NULL, 0);
-    }
-    if (argc > 4) {
+    if (argc > 4)
         extra2 = HDstrtoll(argv[4], NULL, 0);
-    }
+
     /*
      * Read the signature at the specified file position.
      */
@@ -134,7 +134,7 @@ main(int argc, char *argv[])
     }
     if (!HDmemcmp(sig, H5F_SIGNATURE, H5F_SIGNATURE_LEN)) {
         /*
-         * Debug the boot block.
+         * Debug the file's super block.
          */
         status = H5F_debug(f, H5P_DATASET_XFER_DEFAULT, stdout, 0, VCOL);
 
@@ -166,18 +166,18 @@ main(int argc, char *argv[])
         unsigned    ndims;
 
         switch (subtype) {
-        case H5B_SNODE_ID:
-            status = H5G_node_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, extra);
-            break;
-
-	case H5B_ISTORE_ID:
-	    ndims = (unsigned)extra;
-	    status = H5D_istore_debug (f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, ndims);
-	    break;
-
-        default:
-            fprintf(stderr, "Unknown B-tree subtype %u\n", (unsigned)(subtype));
-            HDexit(4);
+            case H5B_SNODE_ID:
+                status = H5G_node_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, extra);
+                break;
+
+            case H5B_ISTORE_ID:
+                ndims = (unsigned)extra;
+                status = H5D_istore_debug (f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL, ndims);
+                break;
+
+            default:
+                fprintf(stderr, "Unknown B-tree subtype %u\n", (unsigned)(subtype));
+                HDexit(4);
         }
 
     } else if (!HDmemcmp(sig, H5B2_HDR_MAGIC, H5B2_SIZEOF_MAGIC)) {
@@ -234,6 +234,12 @@ main(int argc, char *argv[])
                 HDexit(4);
         } /* end switch */
 
+    } else if (!HDmemcmp(sig, H5HF_HDR_MAGIC, H5HF_SIZEOF_MAGIC)) {
+        /*
+         * Debug a fractal heap header.
+         */
+        status = H5HF_hdr_debug(f, H5P_DATASET_XFER_DEFAULT, addr, stdout, 0, VCOL);
+
     } else if (sig[0] == H5O_VERSION) {
         /*
          * This could be an object header.  Since they don't have a signature
@@ -246,7 +252,7 @@ main(int argc, char *argv[])
          * Got some other unrecognized signature.
          */
         printf("%-*s ", VCOL, "Signature:");
-        for (i = 0; i < 8; i++) {
+        for (i = 0; i < sizeof(sig); i++) {
             if (sig[i] > ' ' && sig[i] <= '~' && '\\' != sig[i]) {
                 HDputchar(sig[i]);
             } else if ('\\' == sig[i]) {
@@ -270,5 +276,7 @@ main(int argc, char *argv[])
     H5Pclose(dxpl);
     H5Pclose(fapl);
     H5Fclose(fid);
+
     return 0;
 }
+