[svn-r12935] Added list-to-btree conversion, changed SOHM apis, and pushed SOHM table

version and size information into the superblock to eliminate a read when
loading it.

This is a file format change, and hopefully the last one (knock on wood).

Tested on kagiso and Windows (mostly just a SOHM change).

19 files changed, 491 insertions, 285 deletions

diff --git a/src/H5Edefin.h b/src/H5Edefin.h
index f54228e..e99fe67 100644
--- a/src/H5Edefin.h
+++ b/src/H5Edefin.h
@@ -182,6 +182,13 @@ hid_t H5E_CANTNEXT_g       = FAIL;      /* Can't move to next iterator location
 hid_t H5E_BADSELECT_g      = FAIL;      /* Invalid selection */
 hid_t H5E_CANTCOMPARE_g    = FAIL;      /* Can't compare objects */
 
+/* Argument errors */
+hid_t H5E_UNINITIALIZED_g  = FAIL;      /* Information is uinitialized */
+hid_t H5E_UNSUPPORTED_g    = FAIL;      /* Feature is unsupported */
+hid_t H5E_BADTYPE_g        = FAIL;      /* Inappropriate type */
+hid_t H5E_BADRANGE_g       = FAIL;      /* Out of range */
+hid_t H5E_BADVALUE_g       = FAIL;      /* Bad value */
+
 /* B-tree related errors */
 hid_t H5E_NOTFOUND_g       = FAIL;      /* Object not found */
 hid_t H5E_EXISTS_g         = FAIL;      /* Object already exists */
@@ -195,13 +202,6 @@ hid_t H5E_CANTLIST_g       = FAIL;      /* Unable to list node */
 hid_t H5E_CANTMODIFY_g     = FAIL;      /* Unable to modify record */
 hid_t H5E_CANTREMOVE_g     = FAIL;      /* Unable to remove object */
 
-/* Argument errors */
-hid_t H5E_UNINITIALIZED_g  = FAIL;      /* Information is uinitialized */
-hid_t H5E_UNSUPPORTED_g    = FAIL;      /* Feature is unsupported */
-hid_t H5E_BADTYPE_g        = FAIL;      /* Inappropriate type */
-hid_t H5E_BADRANGE_g       = FAIL;      /* Out of range */
-hid_t H5E_BADVALUE_g       = FAIL;      /* Bad value */
-
 /* Datatype conversion errors */
 hid_t H5E_CANTCONVERT_g    = FAIL;      /* Can't convert datatypes */
 hid_t H5E_BADSIZE_g        = FAIL;      /* Bad size for object */
diff --git a/src/H5Einit.h b/src/H5Einit.h
index 2da01ba..a96f798 100644
--- a/src/H5Einit.h
+++ b/src/H5Einit.h
@@ -688,6 +688,33 @@ if((msg = H5E_create_msg(cls, H5E_MINOR, "Can't compare objects"))==NULL)
 if((H5E_CANTCOMPARE_g = H5I_register(H5I_ERROR_MSG, msg))<0)
     HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
 
+/* Argument errors */
+assert(H5E_UNINITIALIZED_g==(-1));
+if((msg = H5E_create_msg(cls, H5E_MINOR, "Information is uinitialized"))==NULL)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
+if((H5E_UNINITIALIZED_g = H5I_register(H5I_ERROR_MSG, msg))<0)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
+assert(H5E_UNSUPPORTED_g==(-1));
+if((msg = H5E_create_msg(cls, H5E_MINOR, "Feature is unsupported"))==NULL)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
+if((H5E_UNSUPPORTED_g = H5I_register(H5I_ERROR_MSG, msg))<0)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
+assert(H5E_BADTYPE_g==(-1));
+if((msg = H5E_create_msg(cls, H5E_MINOR, "Inappropriate type"))==NULL)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
+if((H5E_BADTYPE_g = H5I_register(H5I_ERROR_MSG, msg))<0)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
+assert(H5E_BADRANGE_g==(-1));
+if((msg = H5E_create_msg(cls, H5E_MINOR, "Out of range"))==NULL)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
+if((H5E_BADRANGE_g = H5I_register(H5I_ERROR_MSG, msg))<0)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
+assert(H5E_BADVALUE_g==(-1));
+if((msg = H5E_create_msg(cls, H5E_MINOR, "Bad value"))==NULL)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
+if((H5E_BADVALUE_g = H5I_register(H5I_ERROR_MSG, msg))<0)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
+
 /* B-tree related errors */
 assert(H5E_NOTFOUND_g==(-1));
 if((msg = H5E_create_msg(cls, H5E_MINOR, "Object not found"))==NULL)
@@ -745,33 +772,6 @@ if((msg = H5E_create_msg(cls, H5E_MINOR, "Unable to remove object"))==NULL)
 if((H5E_CANTREMOVE_g = H5I_register(H5I_ERROR_MSG, msg))<0)
     HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
 
-/* Argument errors */
-assert(H5E_UNINITIALIZED_g==(-1));
-if((msg = H5E_create_msg(cls, H5E_MINOR, "Information is uinitialized"))==NULL)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
-if((H5E_UNINITIALIZED_g = H5I_register(H5I_ERROR_MSG, msg))<0)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
-assert(H5E_UNSUPPORTED_g==(-1));
-if((msg = H5E_create_msg(cls, H5E_MINOR, "Feature is unsupported"))==NULL)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
-if((H5E_UNSUPPORTED_g = H5I_register(H5I_ERROR_MSG, msg))<0)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
-assert(H5E_BADTYPE_g==(-1));
-if((msg = H5E_create_msg(cls, H5E_MINOR, "Inappropriate type"))==NULL)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
-if((H5E_BADTYPE_g = H5I_register(H5I_ERROR_MSG, msg))<0)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
-assert(H5E_BADRANGE_g==(-1));
-if((msg = H5E_create_msg(cls, H5E_MINOR, "Out of range"))==NULL)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
-if((H5E_BADRANGE_g = H5I_register(H5I_ERROR_MSG, msg))<0)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
-assert(H5E_BADVALUE_g==(-1));
-if((msg = H5E_create_msg(cls, H5E_MINOR, "Bad value"))==NULL)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
-if((H5E_BADVALUE_g = H5I_register(H5I_ERROR_MSG, msg))<0)
-    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
-
 /* Datatype conversion errors */
 assert(H5E_CANTCONVERT_g==(-1));
 if((msg = H5E_create_msg(cls, H5E_MINOR, "Can't convert datatypes"))==NULL)
diff --git a/src/H5Epubgen.h b/src/H5Epubgen.h
index 7c517cf..393b6f4 100644
--- a/src/H5Epubgen.h
+++ b/src/H5Epubgen.h
@@ -312,6 +312,18 @@ H5_DLLVAR hid_t H5E_CANTNEXT_g;      /* Can't move to next iterator location */
 H5_DLLVAR hid_t H5E_BADSELECT_g;     /* Invalid selection */
 H5_DLLVAR hid_t H5E_CANTCOMPARE_g;   /* Can't compare objects */
 
+/* Argument errors */
+#define H5E_UNINITIALIZED    (H5OPEN H5E_UNINITIALIZED_g)
+#define H5E_UNSUPPORTED      (H5OPEN H5E_UNSUPPORTED_g)
+#define H5E_BADTYPE          (H5OPEN H5E_BADTYPE_g)
+#define H5E_BADRANGE         (H5OPEN H5E_BADRANGE_g)
+#define H5E_BADVALUE         (H5OPEN H5E_BADVALUE_g)
+H5_DLLVAR hid_t H5E_UNINITIALIZED_g; /* Information is uinitialized */
+H5_DLLVAR hid_t H5E_UNSUPPORTED_g;   /* Feature is unsupported */
+H5_DLLVAR hid_t H5E_BADTYPE_g;       /* Inappropriate type */
+H5_DLLVAR hid_t H5E_BADRANGE_g;      /* Out of range */
+H5_DLLVAR hid_t H5E_BADVALUE_g;      /* Bad value */
+
 /* B-tree related errors */
 #define H5E_NOTFOUND         (H5OPEN H5E_NOTFOUND_g)
 #define H5E_EXISTS           (H5OPEN H5E_EXISTS_g)
@@ -336,18 +348,6 @@ H5_DLLVAR hid_t H5E_CANTLIST_g;      /* Unable to list node */
 H5_DLLVAR hid_t H5E_CANTMODIFY_g;    /* Unable to modify record */
 H5_DLLVAR hid_t H5E_CANTREMOVE_g;    /* Unable to remove object */
 
-/* Argument errors */
-#define H5E_UNINITIALIZED    (H5OPEN H5E_UNINITIALIZED_g)
-#define H5E_UNSUPPORTED      (H5OPEN H5E_UNSUPPORTED_g)
-#define H5E_BADTYPE          (H5OPEN H5E_BADTYPE_g)
-#define H5E_BADRANGE         (H5OPEN H5E_BADRANGE_g)
-#define H5E_BADVALUE         (H5OPEN H5E_BADVALUE_g)
-H5_DLLVAR hid_t H5E_UNINITIALIZED_g; /* Information is uinitialized */
-H5_DLLVAR hid_t H5E_UNSUPPORTED_g;   /* Feature is unsupported */
-H5_DLLVAR hid_t H5E_BADTYPE_g;       /* Inappropriate type */
-H5_DLLVAR hid_t H5E_BADRANGE_g;      /* Out of range */
-H5_DLLVAR hid_t H5E_BADVALUE_g;      /* Bad value */
-
 /* Datatype conversion errors */
 #define H5E_CANTCONVERT      (H5OPEN H5E_CANTCONVERT_g)
 #define H5E_BADSIZE          (H5OPEN H5E_BADSIZE_g)
diff --git a/src/H5Eterm.h b/src/H5Eterm.h
index a188ab4..3825203 100644
--- a/src/H5Eterm.h
+++ b/src/H5Eterm.h
@@ -184,6 +184,13 @@ H5E_CANTNEXT_g=
 H5E_BADSELECT_g=    
 H5E_CANTCOMPARE_g=
 
+/* Argument errors */    
+H5E_UNINITIALIZED_g=    
+H5E_UNSUPPORTED_g=    
+H5E_BADTYPE_g=    
+H5E_BADRANGE_g=    
+H5E_BADVALUE_g=
+
 /* B-tree related errors */    
 H5E_NOTFOUND_g=    
 H5E_EXISTS_g=    
@@ -197,13 +204,6 @@ H5E_CANTLIST_g=
 H5E_CANTMODIFY_g=    
 H5E_CANTREMOVE_g=
 
-/* Argument errors */    
-H5E_UNINITIALIZED_g=    
-H5E_UNSUPPORTED_g=    
-H5E_BADTYPE_g=    
-H5E_BADRANGE_g=    
-H5E_BADVALUE_g=
-
 /* Datatype conversion errors */    
 H5E_CANTCONVERT_g=    
 H5E_BADSIZE_g= (-1);
diff --git a/src/H5F.c b/src/H5F.c
index 01f426c..76f98f3 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -944,6 +944,8 @@ H5F_new(H5F_file_t *shared, hid_t fcpl_id, hid_t fapl_id, H5FD_t *lf)
 	f->shared->base_addr = HADDR_UNDEF;
 	f->shared->freespace_addr = HADDR_UNDEF;
 	f->shared->sohm_addr = HADDR_UNDEF;
+	f->shared->sohm_vers = 0;
+	f->shared->sohm_nindexes = 0;
 	f->shared->driver_addr = HADDR_UNDEF;
         f->shared->lf = lf;
 
@@ -977,7 +979,7 @@ H5F_new(H5F_file_t *shared, hid_t fcpl_id, hid_t fapl_id, H5FD_t *lf)
         /* The shared object header message table gets created later, but if
          * it is present we should use version 2 of the superblock.
          */
-        if(H5P_get(plist, H5F_CRT_SOHM_NINDEXES_NAME, &sohm_indexes)<0)
+        if(H5P_get(plist, H5F_CRT_SHMSG_NINDEXES_NAME, &sohm_indexes)<0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get number of SOHM indexes")
 
         if(sohm_indexes > 0) {
@@ -1412,7 +1414,7 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id, hid_t d
         if(NULL == (c_plist = H5P_object_verify(fcpl_id,H5P_FILE_CREATE)))
             HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, NULL, "can't find object for ID");
 
-        if(H5P_get(c_plist, H5F_CRT_SOHM_NINDEXES_NAME, &num_sohm_indexes)<0)
+        if(H5P_get(c_plist, H5F_CRT_SHMSG_NINDEXES_NAME, &num_sohm_indexes)<0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get SOHM information")
 
         if(num_sohm_indexes > 0)
diff --git a/src/H5Fdbg.c b/src/H5Fdbg.c
index 1377c36..3ac3abc 100644
--- a/src/H5Fdbg.c
+++ b/src/H5Fdbg.c
@@ -127,7 +127,11 @@ H5F_debug(H5F_t *f, hid_t dxpl_id, FILE * stream, int indent, int fwidth)
     HDfprintf(stream, "%*s%-*s %a (rel)\n", indent, "", fwidth,
 	      "Free list address:", f->shared->freespace_addr);
     HDfprintf(stream, "%*s%-*s %a (rel)\n", indent, "", fwidth,
-	      "Shared object header table address:", f->shared->sohm_addr);
+	      "Shared object header message table address:", f->shared->sohm_addr);
+    HDfprintf(stream, "%*s%-*s %u\n", indent, "", fwidth,
+	      "Shared object header message version number:", (unsigned) f->shared->sohm_vers);
+    HDfprintf(stream, "%*s%-*s %u\n", indent, "", fwidth,
+	      "Number of shared object header message indexes:", (unsigned) f->shared->sohm_nindexes);
 
     HDfprintf(stream, "%*s%-*s %a (rel)\n", indent, "", fwidth,
 	      "Address of driver information block:", f->shared->driver_addr);
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index 081c970..a58c413 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -59,7 +59,7 @@
 #endif
 
 /* Maximum size of super-block buffer */
-#define H5F_SUPERBLOCK_SIZE  128
+#define H5F_SUPERBLOCK_SIZE  130
 #define H5F_DRVINFOBLOCK_SIZE  1024
 
 /* Define the HDF5 file signature */
@@ -93,6 +93,8 @@ typedef struct H5F_file_t {
     haddr_t	base_addr;	/* Absolute base address for rel.addrs. */
     haddr_t	freespace_addr;	/* Relative address of free-space info	*/
     haddr_t	sohm_addr;	/* Relative address of shared object header message table */
+    unsigned	sohm_vers;	/* Version of shared message table on disk */
+    unsigned	sohm_nindexes;	/* Number of shared messages indexes in the table */
     haddr_t	driver_addr;	/* File driver information block address*/
     hbool_t     fam_to_sec2;    /* Is h5repart changing driver from family to sec2 */
 
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index 25b8f98..f28c8c1 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -341,10 +341,11 @@ typedef struct H5F_t H5F_t;
 #define H5F_CRT_FREESPACE_VERS_NAME   "free_space_version" /* Free-space version number            */
 #define H5F_CRT_OBJ_DIR_VERS_NAME     "obj_dir_version" /* Object directory version number      */
 #define H5F_CRT_SHARE_HEAD_VERS_NAME  "share_head_version" /* Shared-header format version         */
-#define H5F_CRT_SOHM_NINDEXES_NAME    "num_sohm_indexes" /* Number of shared object header message indexes */
-#define H5F_CRT_INDEX_TYPES_NAME      "sohm_message_types" /* Types of message in each index */
-#define H5F_CRT_SOHM_L2B_NAME      "sohm_list_to_btree"  /* SOHM list maximum size */
-#define H5F_CRT_SOHM_B2L_NAME      "sohm_btree_to_list"  /* SOHM B-tree minimum size */
+#define H5F_CRT_SHMSG_NINDEXES_NAME    "num_shmsg_indexes" /* Number of shared object header message indexes */
+#define H5F_CRT_SHMSG_INDEX_TYPES_NAME "shmsg_message_types" /* Types of message in each index */
+#define H5F_CRT_SHMSG_INDEX_MINSIZE_NAME "shmsg_message_minsize" /* Minimum size of messages in each index */
+#define H5F_CRT_SHMSG_LIST_MAX_NAME    "shmsg_list_max"  /* Shared message list maximum size */
+#define H5F_CRT_SHMSG_BTREE_MIN_NAME   "shmsg_btree_min" /* Shared message B-tree minimum size */
 
 
 
diff --git a/src/H5Fsuper.c b/src/H5Fsuper.c
index 234c08d..a77030c 100644
--- a/src/H5Fsuper.c
+++ b/src/H5Fsuper.c
@@ -240,9 +240,11 @@ H5F_read_superblock(H5F_t *f, hid_t dxpl_id, H5G_loc_t *root_loc, haddr_t addr,
 
     H5F_addr_decode(f, (const uint8_t **)&p, &shared->base_addr/*out*/);
     H5F_addr_decode(f, (const uint8_t **)&p, &shared->freespace_addr/*out*/);
-    /* If the superblock version is greater than 1, read in the shared OH message table address */
+    /* If the superblock version is greater than 1, read in the shared OH message table information */
     if(super_vers > 1) {
         H5F_addr_decode(f, (const uint8_t **)&p, &shared->sohm_addr/*out*/);
+        shared->sohm_vers = *p++;
+        shared->sohm_nindexes = *p++;
     }
     H5F_addr_decode(f, (const uint8_t **)&p, &stored_eoa/*out*/);
     H5F_addr_decode(f, (const uint8_t **)&p, &shared->driver_addr/*out*/);
@@ -374,27 +376,27 @@ H5F_read_superblock(H5F_t *f, hid_t dxpl_id, H5G_loc_t *root_loc, haddr_t addr,
         size_t   sohm_l2b;           /* SOHM list-to-btree cutoff    */
         size_t   sohm_b2l;           /* SOHM btree-to-list cutoff    */
 
+        HDassert(shared->sohm_nindexes > 0 && shared->sohm_nindexes <= H5SM_MAX_NUM_INDEXES);
+
         /* Read in the shared OH message information if there is any */
-        if(H5SM_get_info(f, shared->sohm_addr, &nindexes, index_flags, &sohm_l2b, &sohm_b2l, dxpl_id) < 0)
+        if(H5SM_get_info(f, index_flags, &sohm_l2b, &sohm_b2l, dxpl_id) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to read SOHM table information")
 
-        HDassert(nindexes > 0 && nindexes <= H5SM_MAX_NUM_INDEXES);
-
         /* Set values in the property list */
-        if(H5P_set(c_plist, H5F_CRT_SOHM_NINDEXES_NAME, &nindexes) < 0)
+        if(H5P_set(c_plist, H5F_CRT_SHMSG_NINDEXES_NAME, &(shared->sohm_nindexes)) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set number of SOHM indexes");
-        if(H5P_set(c_plist, H5F_CRT_INDEX_TYPES_NAME, index_flags) < 0)
+        if(H5P_set(c_plist, H5F_CRT_SHMSG_INDEX_TYPES_NAME, index_flags) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set type flags for indexes");
-        if(H5P_set(c_plist, H5F_CRT_SOHM_L2B_NAME, &sohm_l2b) < 0)
+        if(H5P_set(c_plist, H5F_CRT_SHMSG_LIST_MAX_NAME, &sohm_l2b) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set SOHM cutoff in property list");
-        if(H5P_set(c_plist, H5F_CRT_SOHM_B2L_NAME, &sohm_b2l) < 0)
+        if(H5P_set(c_plist, H5F_CRT_SHMSG_BTREE_MIN_NAME, &sohm_b2l) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set SOHM cutoff in property list");
     }
     else
     {
         /* Shared object header messages are disabled */
         nindexes = 0;
-        if(H5P_set(c_plist, H5F_CRT_SOHM_NINDEXES_NAME, &nindexes) < 0)
+        if(H5P_set(c_plist, H5F_CRT_SHMSG_NINDEXES_NAME, &nindexes) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set number of SOHM indexes");
     }
 
@@ -459,7 +461,7 @@ H5F_init_superblock(const H5F_t *f, hid_t dxpl_id)
         + 16                            /* Length of required fixed-size portion */
         + ((super_vers>0) ? 4 : 0)      /* Version specific fixed-size portion */
         + 4 * H5F_sizeof_addr(f)        /* Variable-sized addresses */
-        + (super_vers>1 ? H5F_sizeof_addr(f) : 0) + /*SOHM table address*/
+        + (super_vers>1 ? H5F_sizeof_addr(f) + 2: 0) + /*SOHM table info*/
         + H5G_SIZEOF_ENTRY(f);          /* Size of root group symbol table entry */
 
     /* Compute the size of the driver information block. */
@@ -587,6 +589,8 @@ H5F_write_superblock(H5F_t *f, hid_t dxpl_id)
     H5F_addr_encode(f, &p, f->shared->freespace_addr);
     if(super_vers > 1) {
       H5F_addr_encode(f, &p, f->shared->sohm_addr);
+      *p++ = f->shared->sohm_vers;
+      *p++ = f->shared->sohm_nindexes;
     }
     H5F_addr_encode(f, &p, H5FD_get_eoa(f->shared->lf));
     H5F_addr_encode(f, &p, f->shared->driver_addr);
diff --git a/src/H5Opublic.h b/src/H5Opublic.h
index bb61f8b..9576ff1 100644
--- a/src/H5Opublic.h
+++ b/src/H5Opublic.h
@@ -41,6 +41,22 @@
 #define H5O_COPY_PRESERVE_NULL_FLAG     (0x0020u)   /* Copy NULL messages (empty space) */
 #define H5O_COPY_ALL                    (0x003Fu)   /* All object copying flags (for internal checking) */
 
+/* Flags for shared message indexes.
+ * Pass these flags in using the mesg_type_flags parameter in
+ * H5P_set_shared_mesg_index.
+ * (Developers: These flags correspond to object header message type_ids,
+ * but we need to assign each kind of message to a different bit so that
+ * one index can hold multiple types.)
+ */
+#define H5O_MESG_NONE_FLAG     0x0000          /* No shared messages */
+#define H5O_MESG_SDSPACE_FLAG  0x0001          /* Simple Dataspace Message.  */
+#define H5O_MESG_DTYPE_FLAG	   0x0002          /* Datatype Message.  */
+#define H5O_MESG_FILL_FLAG     0x0004          /* Fill Value Message. */
+#define H5O_MESG_PLINE_FLAG	   0x0008          /* Filter pipeline message.  */
+#define H5O_MESG_ATTR_FLAG	   0x0010          /* Attribute Message.  */
+#define H5O_MESG_ALL_FLAG      (H5O_MESG_SDSPACE_FLAG | H5O_MESG_DTYPE_FLAG | H5O_MESG_FILL_FLAG | H5O_MESG_PLINE_FLAG | H5O_MESG_ATTR_FLAG)
+
+
 typedef struct H5O_stat_t {
     hsize_t size;               /* Total size of object header in file */
     hsize_t free;               /* Free space within object header */
diff --git a/src/H5Pfcpl.c b/src/H5Pfcpl.c
index 7c7012b..b4ba4b9 100644
--- a/src/H5Pfcpl.c
+++ b/src/H5Pfcpl.c
@@ -73,16 +73,18 @@
 #define H5F_CRT_SHARE_HEAD_VERS_SIZE  sizeof(unsigned)
 #define H5F_CRT_SHARE_HEAD_VERS_DEF   HDF5_SHAREDHEADER_VERSION
 /* Definitions for shared object header messages */
-#define H5F_CRT_SOHM_NINDEXES_SIZE    sizeof(unsigned)
-#define H5F_CRT_SOHM_NINDEXES_DEF     (0)
-#define H5F_CRT_INDEX_TYPES_SIZE      sizeof(unsigned[H5SM_MAX_NUM_INDEXES])
-#define H5F_CRT_INDEX_TYPES_DEF       { 0,0,0,0,0,0}
-/*#define H5SM_INDEX_TYPES_DEF       { H5SM_FILL_FLAG |H5SM_SDSPACE_FLAG,H5SM_ATTR_FLAG, 0, H5SM_DTYPE_FLAG,0,H5SM_PLINE_FLAG} JAMES */
-/* Definitions for shared object header list/btree cutoffs */
-#define H5F_CRT_SOHM_L2B_SIZE      sizeof(size_t)
-#define H5F_CRT_SOHM_L2B_DEF       (50)    /* JAMES */
-#define H5F_CRT_SOHM_B2L_SIZE      sizeof(size_t)
-#define H5F_CRT_SOHM_B2L_DEF       (40)    /* JAMES */
+#define H5F_CRT_SHMSG_NINDEXES_SIZE    sizeof(unsigned)
+#define H5F_CRT_SHMSG_NINDEXES_DEF     (0)
+#define H5F_CRT_SHMSG_INDEX_TYPES_SIZE sizeof(unsigned[H5SM_MAX_NUM_INDEXES])
+#define H5F_CRT_SHMSG_INDEX_TYPES_DEF  {0,0,0,0,0,0}
+// JAMES #define H5F_CRT_SHMSG_INDEX_TYPES_DEF       { H5O_MESG_FILL_FLAG |H5O_MESG_SDSPACE_FLAG,H5O_MESG_ATTR_FLAG, 0, H5O_MESG_DTYPE_FLAG,0,H5O_MESG_PLINE_FLAG}
+#define H5F_CRT_SHMSG_INDEX_MINSIZE_SIZE sizeof(unsigned[H5SM_MAX_NUM_INDEXES])
+#define H5F_CRT_SHMSG_INDEX_MINSIZE_DEF {250,250,250,250,250,250}
+/* Definitions for shared object header list/btree phase change cutoffs */
+#define H5F_CRT_SHMSG_LIST_MAX_SIZE     sizeof(unsigned)
+#define H5F_CRT_SHMSG_LIST_MAX_DEF      (50)
+#define H5F_CRT_SHMSG_BTREE_MIN_SIZE    sizeof(unsigned)
+#define H5F_CRT_SHMSG_BTREE_MIN_DEF     (40)
 
 
 /******************/
@@ -108,7 +110,7 @@ static herr_t H5P_fcrt_reg_prop(H5P_genclass_t *pclass);
 
 /* File creation property list class library initialization object */
 const H5P_libclass_t H5P_CLS_FCRT[1] = {{
-    "file create",		/* Class name for debugging     */
+    "file create",		/* Class name for debugging     */ 
     &H5P_CLS_GROUP_CREATE_g,	/* Parent class ID              */
     &H5P_CLS_FILE_CREATE_g,	/* Pointer to class ID          */
     &H5P_LST_FILE_CREATE_g,	/* Pointer to default property list ID */
@@ -156,10 +158,11 @@ H5P_fcrt_reg_prop(H5P_genclass_t *pclass)
     unsigned freespace_ver = H5F_CRT_FREESPACE_VERS_DEF;/* Default free space version # */
     unsigned objectdir_ver = H5F_CRT_OBJ_DIR_VERS_DEF;  /* Default object directory version # */
     unsigned sharedheader_ver = H5F_CRT_SHARE_HEAD_VERS_DEF;    /* Default shared header message version # */
-    unsigned        num_sohm_indexes    = H5F_CRT_SOHM_NINDEXES_DEF;
-    unsigned        sohm_index_flags[H5SM_MAX_NUM_INDEXES]    = H5F_CRT_INDEX_TYPES_DEF;
-    size_t         sohm_list_to_btree  = H5F_CRT_SOHM_L2B_DEF;
-    size_t         sohm_btree_to_list  = H5F_CRT_SOHM_B2L_DEF;
+    unsigned        num_sohm_indexes    = H5F_CRT_SHMSG_NINDEXES_DEF;
+    unsigned        sohm_index_flags[H5SM_MAX_NUM_INDEXES]    = H5F_CRT_SHMSG_INDEX_TYPES_DEF;
+    unsigned        sohm_index_minsizes[H5SM_MAX_NUM_INDEXES] = H5F_CRT_SHMSG_INDEX_MINSIZE_DEF;
+    size_t         sohm_list_max  = H5F_CRT_SHMSG_LIST_MAX_DEF;
+    size_t         sohm_btree_min  = H5F_CRT_SHMSG_BTREE_MIN_DEF;
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5P_fcrt_reg_prop)
@@ -201,15 +204,17 @@ H5P_fcrt_reg_prop(H5P_genclass_t *pclass)
          HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
     /* Register the shared OH message information */
-    if(H5P_register(pclass,H5F_CRT_SOHM_NINDEXES_NAME, H5F_CRT_SOHM_NINDEXES_SIZE, &num_sohm_indexes,NULL,NULL,NULL,NULL,NULL,NULL,NULL)<0)
+    if(H5P_register(pclass,H5F_CRT_SHMSG_NINDEXES_NAME, H5F_CRT_SHMSG_NINDEXES_SIZE, &num_sohm_indexes,NULL,NULL,NULL,NULL,NULL,NULL,NULL)<0)
          HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
-    if(H5P_register(pclass,H5F_CRT_INDEX_TYPES_NAME, H5F_CRT_INDEX_TYPES_SIZE, &sohm_index_flags,NULL,NULL,NULL,NULL,NULL,NULL,NULL)<0)
+    if(H5P_register(pclass,H5F_CRT_SHMSG_INDEX_TYPES_NAME, H5F_CRT_SHMSG_INDEX_TYPES_SIZE, &sohm_index_flags,NULL,NULL,NULL,NULL,NULL,NULL,NULL)<0)
+         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+    if(H5P_register(pclass,H5F_CRT_SHMSG_INDEX_MINSIZE_NAME, H5F_CRT_SHMSG_INDEX_MINSIZE_SIZE, &sohm_index_minsizes,NULL,NULL,NULL,NULL,NULL,NULL,NULL)<0)
          HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
     /* Register the shared OH cutoff size information */
-    if(H5P_register(pclass,H5F_CRT_SOHM_L2B_NAME, H5F_CRT_SOHM_L2B_SIZE, &sohm_list_to_btree,NULL,NULL,NULL,NULL,NULL,NULL,NULL)<0)
+    if(H5P_register(pclass,H5F_CRT_SHMSG_LIST_MAX_NAME, H5F_CRT_SHMSG_LIST_MAX_SIZE, &sohm_list_max,NULL,NULL,NULL,NULL,NULL,NULL,NULL)<0)
          HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
-    if(H5P_register(pclass,H5F_CRT_SOHM_B2L_NAME, H5F_CRT_SOHM_B2L_SIZE, &sohm_btree_to_list,NULL,NULL,NULL,NULL,NULL,NULL,NULL)<0)
+    if(H5P_register(pclass,H5F_CRT_SHMSG_BTREE_MIN_NAME, H5F_CRT_SHMSG_BTREE_MIN_SIZE, &sohm_btree_min,NULL,NULL,NULL,NULL,NULL,NULL,NULL)<0)
          HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
 done:
@@ -727,12 +732,12 @@ H5Pset_shared_mesgs(hid_t plist_id, unsigned nindexes, const unsigned mesg_type_
     if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_CREATE)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
 
-    flags_used = H5SM_NONE_FLAG;
+    flags_used = H5O_MESG_NONE_FLAG;
 
     for (i=0; i<nindexes; i++) {
-        if (mesg_type_flags[i] == H5SM_NONE_FLAG)
+        if (mesg_type_flags[i] == H5O_MESG_NONE_FLAG)
             HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "at least one flag must be set");
-        if (mesg_type_flags[i] != (mesg_type_flags[i] & H5SM_ALL_FLAG))
+        if (mesg_type_flags[i] != (mesg_type_flags[i] & H5O_MESG_ALL_FLAG))
             HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "invalid mesg type flag set");
         if (mesg_type_flags[i] & flags_used)
             HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "flag set for two different indexes");
@@ -740,9 +745,9 @@ H5Pset_shared_mesgs(hid_t plist_id, unsigned nindexes, const unsigned mesg_type_
         flags_used |= mesg_type_flags[i]; /* Make sure the user doesn't re-use a flag */
     } /* end for */
 
-    if(H5P_set(plist, H5F_CRT_SOHM_NINDEXES_NAME, &nindexes) < 0)
+    if(H5P_set(plist, H5F_CRT_SHMSG_NINDEXES_NAME, &nindexes) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set number of SOHM indexes");
-    if(H5P_set(plist, H5F_CRT_INDEX_TYPES_NAME, type_flags) < 0)
+    if(H5P_set(plist, H5F_CRT_SHMSG_INDEX_TYPES_NAME, type_flags) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set type flags for indexes");
 
 done:
@@ -751,10 +756,14 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5Pget_shared_nindexes
+ * Function:	H5Pset_shared_mesg_nindexes
  *
- * Purpose:	Get the number of Shared Object Header Message (SOHM)
- *              indexes specified in this property list.
+ * Purpose:	Set the number of Shared Object Header Message (SOHM)
+ *              indexes specified in this property list.  If this is
+ *              zero then shared object header messages are disabled
+ *              for this file.
+ *
+ *              These indexes can be configured with JAMES
  *
  * Return:	Non-negative on success/Negative on failure
  *
@@ -764,93 +773,70 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_shared_nindexes(hid_t plist_id, unsigned *nindexes)
+H5Pset_shared_mesg_nindexes(hid_t plist_id, unsigned nindexes)
 {
     H5P_genplist_t *plist;      /* Property list pointer */
     herr_t      ret_value=SUCCEED;       /* Return value */
 
-    FUNC_ENTER_API(H5Pget_shared_nindexes, FAIL);
-    H5TRACE2("e","i*Iu",plist_id,nindexes);
+    FUNC_ENTER_API(H5Pset_shared_mesg_nindexes, FAIL);
+    H5TRACE2("e","iIu",plist_id,nindexes);
+
+    /* Check argument */
+    if (nindexes > H5SM_MAX_NUM_INDEXES)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "number of indexes is greater than H5SM_MAX_NUM_INDEXES");
 
     /* Get the plist structure */
     if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_CREATE)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
 
-    if(H5P_get(plist, H5F_CRT_SOHM_NINDEXES_NAME, nindexes) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get number of indexes");
+    if(H5P_set(plist, H5F_CRT_SHMSG_NINDEXES_NAME, &nindexes) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set number of indexes");
 
 done:
     FUNC_LEAVE_API(ret_value);
-
 }
 
+
 /*-------------------------------------------------------------------------
- * Function:	H5Pget_shared_mesg_types
- *
- * Purpose:	Get the mesg_type_flags array for this property list.
- *              At most max_nindexes values will be copied to the
- *              mesg_type_flags array.
+ * Function:	H5Pget_shared_imesg_nindexes
  *
- *              Each entry in the array represents the types of messages
- *              to be shared in the corresponding Shared Object Header
- *              Message (SOHM) index.
+ * Purpose:	Get the number of Shared Object Header Message (SOHM)
+ *              indexes specified in this property list.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	James Laird
- *		Wednesday, April 5, 2006
+ *		Monday, October 9, 2006
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_shared_mesg_types(hid_t plist_id, unsigned max_nindexes, unsigned mesg_type_flags[])
+H5Pget_shared_mesg_nindexes(hid_t plist_id, unsigned *nindexes)
 {
     H5P_genplist_t *plist;      /* Property list pointer */
-    unsigned nindexes;               /* Number of SOHM indexes */
     herr_t      ret_value=SUCCEED;       /* Return value */
 
-    FUNC_ENTER_API(H5Pget_shared_mesg_types, FAIL);
-    H5TRACE3("e","iIu*Iu",plist_id,max_nindexes,mesg_type_flags);
+    FUNC_ENTER_API(H5Pget_shared_mesg_nindexes, FAIL);
+    H5TRACE2("e","i*Iu",plist_id,nindexes);
 
     /* Get the plist structure */
     if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_CREATE)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
 
-    if(H5P_get(plist, H5F_CRT_SOHM_NINDEXES_NAME, &nindexes) < 0)
+    if(H5P_get(plist, H5F_CRT_SHMSG_NINDEXES_NAME, nindexes) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get number of indexes");
 
-    if(mesg_type_flags) {
-        unsigned	i;
-        unsigned        type_flags[H5SM_MAX_NUM_INDEXES];
-
-        /* JAMES: make this H5F_CRT_SOHM_IDX_TYPES_NAME or something? */
-        if(H5P_get(plist, H5F_CRT_INDEX_TYPES_NAME, type_flags) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get index types");
-
-        /* Get the flags */
-        for (i=0; i<nindexes && i<max_nindexes; ++i)
-            mesg_type_flags[i] = type_flags[i];
-    } /* end if */
-
 done:
     FUNC_LEAVE_API(ret_value);
-}
 
+}
 
 /*-------------------------------------------------------------------------
- * Function:	H5Pset_sohm_list_max
+ * Function:	H5Pset_shared_mesg_index
  *
- * Purpose:	Sets the maximum size for a list storing Shared Object
- *              Header Messages in this file.  If more than this many
- *              messages are stored in an index, that index will become a
- *              B-tree.
- *
- *              This value must be no greater than the list maximum plus
- *              one (i.e., there cannot be any values which are too many
- *              for a list but too few for a B-tree).
- *
- *              If this is zero then SOHM indexes in this file will never
- *              be lists but will be created as B-trees.
+ * Purpose:	Configure a given shared message index.  Sets the types of
+ *              message that should be stored in this index and the minimum
+ *              size of a message in the index.
  *
  * Return:	Non-negative on success/Negative on failure
  *
@@ -860,32 +846,69 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pset_sohm_list_max(hid_t plist_id, size_t max)
+H5Pset_shared_mesg_index(hid_t plist_id, unsigned index_num, unsigned mesg_type_flags, unsigned min_mesg_size)
 {
     H5P_genplist_t *plist;      /* Property list pointer */
+    unsigned    nindexes;               /* Number of SOHM indexes */
+    unsigned    type_flags[H5SM_MAX_NUM_INDEXES]; /* Array of mesg_type_flags*/
+    unsigned    minsizes[H5SM_MAX_NUM_INDEXES]; /* Array of min_mesg_sizes*/
+    unsigned    x;
     herr_t      ret_value=SUCCEED;       /* Return value */
 
-    FUNC_ENTER_API(H5Pset_sohm_list_max, FAIL);
-    H5TRACE2("e","iz",plist_id,max);
+    FUNC_ENTER_API(H5Pset_shared_mesg_index, FAIL);
+    H5TRACE4("e","iIuIuIu",plist_id,index_num,mesg_type_flags,min_mesg_size);
+
+    /* Check arguments */
+    if(index_num == 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "index_num must be at least 1");
+    if(mesg_type_flags > H5O_MESG_ALL_FLAG)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "unrecognized flags in mesg_type_flags");
 
     /* Get the plist structure */
     if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_CREATE)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
 
-    /* No need to check value in max, since it cannot be negative */
-    if(H5P_set(plist, H5F_CRT_SOHM_L2B_NAME, &max) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set SOHM information");
+    /* Read the current number of indexes */
+    if(H5P_get(plist, H5F_CRT_SHMSG_NINDEXES_NAME, &nindexes) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get number of indexes");
+
+    if(index_num > nindexes)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "index_num is greater than number of indexes in property list");
+
+    /* Get arrays of type flags and message sizes */
+    if(H5P_get(plist, H5F_CRT_SHMSG_INDEX_TYPES_NAME, type_flags) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get current index type flags")
+    if(H5P_get(plist, H5F_CRT_SHMSG_INDEX_MINSIZE_NAME, minsizes) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get current min sizes")
+
+    /* Set values in arrays */
+    type_flags[index_num - 1] = mesg_type_flags;
+    minsizes[index_num - 1] = min_mesg_size;
+
+    /* Check that type flags does introduce any duplicate values */
+    for(x=0; x < nindexes; ++x) {
+        if(x != (index_num - 1) && (type_flags[index_num - 1] & type_flags[x]) != 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_BADVALUE, FAIL, "can't assign the same flag to different indexes")
+    }
+
+    /* Write arrays back to plist */
+    if(H5P_set(plist, H5F_CRT_SHMSG_INDEX_TYPES_NAME, type_flags) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set index type flags");
+    if(H5P_set(plist, H5F_CRT_SHMSG_INDEX_MINSIZE_NAME, minsizes) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set min mesg sizes");
 
 done:
     FUNC_LEAVE_API(ret_value);
 }
 
 
+
 /*-------------------------------------------------------------------------
- * Function:	H5Pget_sohm_list_max
+ * Function:	H5Pget_shared_mesg_index
  *
- * Purpose:	Gets the maximum size of a SOHM list index before it becomes
- *              a B-tree.
+ * Purpose:	Get information about a given shared message index.  Gets
+ *              the types of message that are stored in the index and the
+ *              minimum size of a message in the index.
  *
  * Return:	Non-negative on success/Negative on failure
  *
@@ -895,39 +918,61 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_sohm_list_max(hid_t plist_id, size_t *max)
+H5Pget_shared_mesg_index(hid_t plist_id, unsigned index_num, unsigned *mesg_type_flags, unsigned *min_mesg_size)
 {
     H5P_genplist_t *plist;      /* Property list pointer */
+    unsigned    nindexes;               /* Number of SOHM indexes */
+    unsigned    type_flags[H5SM_MAX_NUM_INDEXES]; /* Array of mesg_type_flags*/
+    unsigned    minsizes[H5SM_MAX_NUM_INDEXES]; /* Array of min_mesg_sizes*/
     herr_t      ret_value=SUCCEED;       /* Return value */
 
-    FUNC_ENTER_API(H5Pget_sohm_list_max, FAIL);
-    H5TRACE2("e","i*z",plist_id,max);
+    FUNC_ENTER_API(H5Pget_shared_mesg_index, FAIL);
+    H5TRACE4("e","iIu*Iu*Iu",plist_id,index_num,mesg_type_flags,min_mesg_size);
+
+    /* Check arguments */
+    if(index_num == 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "index_num must be at least 1")
 
     /* Get the plist structure */
     if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_CREATE)))
-        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
 
-    /* Get value */
-    if (max) {
-        if(H5P_get(plist, H5F_CRT_SOHM_L2B_NAME, max) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get SOHM information");
-    }
+    /* Read the current number of indexes */
+    if(H5P_get(plist, H5F_CRT_SHMSG_NINDEXES_NAME, &nindexes) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get number of indexes")
+
+    if(index_num > nindexes)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "index_num is greater than number of indexes in property list")
+
+    /* Get arrays of type flags and message sizes */
+    if(H5P_get(plist, H5F_CRT_SHMSG_INDEX_TYPES_NAME, type_flags) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get current index type flags")
+    if(H5P_get(plist, H5F_CRT_SHMSG_INDEX_MINSIZE_NAME, minsizes) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get current min sizes")
+
+    /* Get values from arrays */
+    if(mesg_type_flags)
+        *mesg_type_flags = type_flags[index_num - 1];
+    if(min_mesg_size)
+        *min_mesg_size = minsizes[index_num - 1];
 
 done:
     FUNC_LEAVE_API(ret_value);
 }
+
 
+
 /*-------------------------------------------------------------------------
- * Function:	H5Pset_sohm_btree_min
+ * Function:	H5Pset_shared_mesg_phase_change
  *
- * Purpose:	Sets the minimum size for a B-tree storing Shared Object
- *              Header Messages in this file.  If fewer than this many
- *              messages are stored in an index, that index will become a
- *              list.
+ * Purpose:	Sets the cutoff values for indexes storing shared object
+ *              header messages in this file.  If more than max_list
+ *              messages are in an index, that index will become a B-tree.
+ *              Likewise, a B-tree index containing fewer than min_btree
+ *              messages will be converted to a list.
  *
- *              This value must be no greater than the list maximum plus
- *              one (i.e., there cannot be any values which are too many
- *              for a list but too few for a B-tree).
+ *              If the max_list is zero then SOHM indexes in this file will
+ *              never be lists but will be created as B-trees.
  *
  * Return:	Non-negative on success/Negative on failure
  *
@@ -937,21 +982,35 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pset_sohm_btree_min(hid_t plist_id, size_t min)
+H5Pset_shared_mesg_phase_change(hid_t plist_id, unsigned max_list, unsigned min_btree)
 {
     H5P_genplist_t *plist;      /* Property list pointer */
     herr_t      ret_value=SUCCEED;       /* Return value */
 
-    FUNC_ENTER_API(H5Pset_sohm_btree_min, FAIL);
-    H5TRACE2("e","iz",plist_id,min);
+    FUNC_ENTER_API(H5Pset_shared_mesg_phase_change, FAIL);
+    H5TRACE3("e","iIuIu",plist_id,max_list,min_btree);
+
+    /* Check that values are sensible.  The min_btree value must be no greater
+     * than the max list plus one.
+     * No need to check values otherwise, since they can't be negative.
+     */
+    if(max_list + 1 < min_btree)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "minimum B-tree value is greater than maximum list value")
+
+    /* Avoid the strange case where max_list == 0 and min_btree == 1, so deleting the
+     * last message in a B-tree makes it become an empty list.
+     */
+    if(max_list == 0)
+        min_btree = 0;
 
     /* Get the plist structure */
     if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_CREATE)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
 
-    /* No need to check value in min, since it cannot be negative */
-    if(H5P_set(plist, H5F_CRT_SOHM_B2L_NAME, &min) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set SOHM information");
+    if(H5P_set(plist, H5F_CRT_SHMSG_LIST_MAX_NAME, &max_list) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set list maximum in property list");
+    if(H5P_set(plist, H5F_CRT_SHMSG_BTREE_MIN_NAME, &min_btree) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set B-tree minimum in property list");
 
 done:
     FUNC_LEAVE_API(ret_value);
@@ -959,38 +1018,42 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5Pget_sohm_btree_min
+ * Function:	H5Pget_sohm_list_max
  *
- * Purpose:	Gets the minimum size of a SOHM B-tree index before it becomes
- *              a list.
+ * Purpose:	Gets the maximum size of a SOHM list index before it becomes
+ *              a B-tree.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	James Laird
- *		Thursday, May 11, 2006
+ *		Wednesday, April 5, 2006
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_sohm_btree_min(hid_t plist_id, size_t *min)
+H5Pget_shared_mesg_phase_change(hid_t plist_id, unsigned *max_list, unsigned *min_btree)
 {
     H5P_genplist_t *plist;      /* Property list pointer */
     herr_t      ret_value=SUCCEED;       /* Return value */
 
-    FUNC_ENTER_API(H5Pget_sohm_btree_min, FAIL);
-    H5TRACE2("e","i*z",plist_id,min);
+    FUNC_ENTER_API(H5Pget_shared_mesg_phase_change, FAIL);
+    H5TRACE3("e","i*Iu*Iu",plist_id,max_list,min_btree);
 
     /* Get the plist structure */
     if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_CREATE)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
 
     /* Get value */
-    if (min) {
-        if(H5P_get(plist, H5F_CRT_SOHM_B2L_NAME, min) < 0)
+    if (max_list) {
+        if(H5P_get(plist, H5F_CRT_SHMSG_LIST_MAX_NAME, max_list) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get list maximum");
+    }
+    if (min_btree) {
+        if(H5P_get(plist, H5F_CRT_SHMSG_BTREE_MIN_NAME, min_btree) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get SOHM information");
     }
 
 done:
     FUNC_LEAVE_API(ret_value);
 }
-
+
diff --git a/src/H5Ppublic.h b/src/H5Ppublic.h
index 2620652..ea929b8 100644
--- a/src/H5Ppublic.h
+++ b/src/H5Ppublic.h
@@ -227,13 +227,12 @@ H5_DLL herr_t H5Pset_sym_k(hid_t plist_id, unsigned ik, unsigned lk);
 H5_DLL herr_t H5Pget_sym_k(hid_t plist_id, unsigned *ik/*out*/, unsigned *lk/*out*/);
 H5_DLL herr_t H5Pset_istore_k(hid_t plist_id, unsigned ik);
 H5_DLL herr_t H5Pget_istore_k(hid_t plist_id, unsigned *ik/*out*/);
-H5_DLL herr_t H5Pset_shared_mesgs(hid_t plist_id, unsigned nindexes, const unsigned * mesg_type_flags);
-H5_DLL herr_t H5Pget_shared_nindexes(hid_t plist_id, unsigned *nindexes);
-H5_DLL herr_t H5Pget_shared_mesg_types(hid_t plist_id, unsigned max_nindexes, unsigned * mesg_type_flags);
-H5_DLL herr_t H5Pset_sohm_list_max(hid_t plist_id, size_t max);
-H5_DLL herr_t H5Pget_sohm_list_max(hid_t plist_id, size_t *max);
-H5_DLL herr_t H5Pset_sohm_btree_min(hid_t plist_id, size_t min);
-H5_DLL herr_t H5Pget_sohm_btree_min(hid_t plist_id, size_t *min);
+H5_DLL herr_t H5Pset_shared_mesg_nindexes(hid_t plist_id, unsigned nindexes);
+H5_DLL herr_t H5Pget_shared_mesg_nindexes(hid_t plist_id, unsigned *nindexes);
+H5_DLL herr_t H5Pset_shared_mesg_index(hid_t plist_id, unsigned index_num, unsigned mesg_type_flags, unsigned min_mesg_size);
+H5_DLL herr_t H5Pget_shared_mesg_index(hid_t plist_id, unsigned index_num, unsigned *mesg_type_flags, unsigned *min_mesg_size);
+H5_DLL herr_t H5Pset_shared_mesg_phase_change(hid_t plist_id, unsigned max_list, unsigned min_btree);
+H5_DLL herr_t H5Pget_shared_mesg_phase_change(hid_t plist_id, unsigned *max_list, unsigned *min_btree);
 
 
 /* File access property list (FAPL) routines */
diff --git a/src/H5SM.c b/src/H5SM.c
index 79d0c05..6c0e3b5 100755
--- a/src/H5SM.c
+++ b/src/H5SM.c
@@ -52,9 +52,6 @@
 /* Local Prototypes */
 /********************/
 static herr_t H5SM_create_index(H5F_t *f, H5SM_index_header_t *header, hid_t dxpl_id);
-/* JAMES
-static herr_t H5SM_write_index(H5F_t *f, haddr_t index_addr, hsize_t sohm_hash, haddr_t sohm_addr, hid_t dxpl_id);
-*/
 static haddr_t H5SM_create_list(H5F_t *f, H5SM_index_header_t *header, hid_t dxpl_id);
 static herr_t H5SM_write_mesg(H5F_t *f, hid_t dxpl_id, H5SM_index_header_t *header,
      unsigned type_id, void *mesg, unsigned *cache_flags_ptr);
@@ -105,7 +102,7 @@ H5SM_init(H5F_t *f, H5P_genplist_t * fc_plist, hid_t dxpl_id)
     H5SM_master_table_t *table = NULL;
     haddr_t table_addr = HADDR_UNDEF;
     unsigned num_indexes;
-    size_t list_to_btree, btree_to_list;
+    unsigned list_to_btree, btree_to_list;
     unsigned index_type_flags[H5SM_MAX_NUM_INDEXES];
     ssize_t x;
     hsize_t table_size;
@@ -122,27 +119,31 @@ H5SM_init(H5F_t *f, H5P_genplist_t * fc_plist, hid_t dxpl_id)
 	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for SOHM table")
 
     /* Get information from fcpl */
-    if(H5P_get(fc_plist, H5F_CRT_SOHM_NINDEXES_NAME, &num_indexes)<0)
+    if(H5P_get(fc_plist, H5F_CRT_SHMSG_NINDEXES_NAME, &num_indexes)<0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get SOHM information")
-    if(H5P_get(fc_plist, H5F_CRT_INDEX_TYPES_NAME, &index_type_flags)<0)
+    if(H5P_get(fc_plist, H5F_CRT_SHMSG_INDEX_TYPES_NAME, &index_type_flags)<0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get SOHM information")
-    if(H5P_get(fc_plist, H5F_CRT_SOHM_L2B_NAME, &list_to_btree)<0)
+    if(H5P_get(fc_plist, H5F_CRT_SHMSG_LIST_MAX_NAME, &list_to_btree)<0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get SOHM information")
-    if(H5P_get(fc_plist, H5F_CRT_SOHM_B2L_NAME, &btree_to_list)<0)
+    if(H5P_get(fc_plist, H5F_CRT_SHMSG_BTREE_MIN_NAME, &btree_to_list)<0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get SOHM information")
 
-    /* Right now we just use one byte to hold the number of indexes */
+    /* Set version and number of indexes in table and in superblock.
+     * Right now we just use one byte to hold the number of indexes.
+     */
     HDassert(num_indexes < 256);
     table->num_indexes = num_indexes;
+    table->version = H5SM_MASTER_TABLE_VERSION;
+
+    f->shared->sohm_nindexes = table->num_indexes;
+    f->shared->sohm_vers = table->version;
 
     /* Check that list and btree cutoffs make sense.  There can't be any
      * values greater than the list max but less than the btree min; the
      * list max has to be greater than or equal to one less than the btree
      * min.
      */
-    if(list_to_btree + 1 < btree_to_list)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "SOHM list max is less than btree min")
-
+    HDassert(list_to_btree + 1 >= btree_to_list);
     HDassert(table->num_indexes > 0 && table->num_indexes <= H5SM_MAX_NUM_INDEXES);
 
     /* Allocate the SOHM indexes as an array. */
@@ -224,19 +225,19 @@ H5SM_get_index(const H5SM_master_table_t *table, unsigned type_id)
     switch(type_id)
     {
     case H5O_SDSPACE_ID:
-        type_flag = H5SM_SDSPACE_FLAG;
+        type_flag = H5O_MESG_SDSPACE_FLAG;
         break;
     case H5O_DTYPE_ID:
-        type_flag = H5SM_DTYPE_FLAG;
+        type_flag = H5O_MESG_DTYPE_FLAG;
         break;
     case H5O_FILL_NEW_ID:
-        type_flag = H5SM_FILL_FLAG;
+        type_flag = H5O_MESG_FILL_FLAG;
         break;
     case H5O_PLINE_ID:
-        type_flag = H5SM_PLINE_FLAG;
+        type_flag = H5O_MESG_PLINE_FLAG;
         break;
     case H5O_ATTR_ID:
-        type_flag = H5SM_ATTR_FLAG;
+        type_flag = H5O_MESG_ATTR_FLAG;
         break;
     default:
         HGOTO_ERROR(H5E_OHDR, H5E_BADTYPE, FAIL, "unknown message type ID")
@@ -502,7 +503,7 @@ H5SM_try_share(H5F_t *f, hid_t dxpl_id, unsigned type_id, void *mesg)
     /* If the message isn't big enough, don't bother sharing it */
     if((mesg_size = H5O_mesg_size(type_id, f, mesg, 0)) <0)
 	HGOTO_ERROR(H5E_OHDR, H5E_BADMESG, FAIL, "unable to get OH message size")
-    if(mesg_size < 15) /* JAMES: arbitrary value.  Make this per-index, along with index sizes? */
+    if(mesg_size < 50) /* JAMES: arbitrary value.  Make this per-index, along with index sizes? */
         HGOTO_DONE(FALSE);
 
     /* JAMES_HEAP: skip this step if it's already shared--just increment the refcount on the message itself */
@@ -679,7 +680,43 @@ H5SM_write_mesg(H5F_t *f, hid_t dxpl_id, H5SM_index_header_t *header,
         if(H5HF_insert(fheap, dxpl_id, mesg_size, key.encoding, &(shared.u.heap_id)) < 0)
             HGOTO_ERROR(H5E_HEAP, H5E_CANTINSERT, FAIL, "unable to insert message into fractal heap")
 
-        /* JAMES: this is where we should check for conversion to B-tree. */
+        /* Check whether the list has grown enough that it needs to become a B-tree */
+        /* JAMES: make this a separate function */
+        if(header->index_type == H5SM_LIST && header->num_messages > header->list_to_btree)
+        {
+            hsize_t     list_size;        /* Size of list on disk */
+            haddr_t     tree_addr;
+
+            if(H5B2_create(f, dxpl_id, H5SM_INDEX, H5SM_B2_NODE_SIZE,
+                  H5SM_SOHM_ENTRY_SIZE(f), H5SM_B2_SPLIT_PERCENT,
+                  H5SM_B2_MERGE_PERCENT, &tree_addr) <0)
+                HGOTO_ERROR(H5E_BTREE, H5E_CANTCREATE, FAIL, "B-tree creation failed for SOHM index")
+
+            /* Insert each record into the new B-tree */
+            for(x=0; x<header->list_to_btree; x++)
+            {
+                /* JAMES: I'd like to stop relying on H5O_HASH_UNDEF */
+                if(list->messages[x].hash != H5O_HASH_UNDEF)
+                {
+                    if(H5B2_insert(f, dxpl_id, H5SM_INDEX, tree_addr, &(list->messages[x])) < 0)
+                        HGOTO_ERROR(H5E_BTREE, H5E_CANTINSERT, FAIL, "couldn't add SOHM to B-tree")
+                }
+            }
+
+            /* Delete the old list */
+            HDassert(list);
+            if(H5AC_unprotect(f, dxpl_id, H5AC_SOHM_LIST, header->index_addr, list, H5AC__DELETED_FLAG) < 0)
+	        HGOTO_ERROR(H5E_CACHE, H5E_CANTUNPROTECT, FAIL, "unable to close SOHM index")
+            list = NULL;
+
+            list_size = H5SM_LIST_SIZE(f, header->list_to_btree);
+            if(H5MF_xfree(f, H5FD_MEM_SOHM, dxpl_id, header->index_addr, list_size) < 0)
+	        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, HADDR_UNDEF, "unable to free shared message list")
+
+            header->index_addr = tree_addr;
+            header->index_type = H5SM_BTREE;
+        }
+
 
         /* JAMES: should be H5SM_insert or something */
         /* Find an empty spot in the list for the message JAMES: combine this with the previous traversal */
@@ -928,6 +965,43 @@ H5SM_delete_from_index(H5F_t *f, hid_t dxpl_id, H5SM_index_header_t *header, uns
         /* Update the index header, so set its dirty flag */
         --header->num_messages;
         *cache_flags |= H5AC__DIRTIED_FLAG;
+
+        /* If we've just passed the btree-to-list cutoff, convert this B-tree
+         * into a list
+         */
+        /* JAMES: there's an off-by-one error here */
+        /* JAMES: make this a separate function */
+        if(header->num_messages < header->btree_to_list)
+        {
+            /* Remember the btree address for this index; we'll overwrite the
+             * address in the index header
+             */
+            haddr_t btree_addr = header->index_addr;
+            H5SM_index_header_t temp_header;
+
+            /* The protect callback expects a header corresponding to the list
+             * index.  Create a "temporary" header to hold the old B-tree
+             * index and reset values in the "real" header to point to an
+             * empty list index.
+             */
+            HDmemcpy(&temp_header, header, sizeof(H5SM_index_header_t));
+            header->num_messages = 0;
+            header->index_type = H5SM_LIST;
+
+            /* Create a new list index */
+            if(HADDR_UNDEF == (header->index_addr = H5SM_create_list(f, header, dxpl_id)))
+                HGOTO_ERROR(H5E_SOHM, H5E_CANTINIT, FAIL, "unable to create shared message list")
+
+            HDassert(NULL == list);
+            if (NULL == (list = H5AC_protect(f, dxpl_id, H5AC_SOHM_LIST, header->index_addr, NULL, header, H5AC_WRITE)))
+	        HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM index")
+
+            /* Delete the B-tree and have messages copy themselves to the
+             * list as they're deleted
+             */
+            if(H5B2_delete(f, dxpl_id, H5SM_INDEX, temp_header.index_addr, H5SM_convert_to_list_op, list) < 0)
+                HGOTO_ERROR(H5E_BTREE, H5E_CANTDELETE, FAIL, "unable to delete B-tree")
+        }
     }
 
 done:
@@ -961,23 +1035,35 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-herr_t H5SM_get_info(H5F_t *f, haddr_t table_addr, unsigned *nindexes,
-              unsigned *index_flags, size_t *list_to_btree,
+herr_t H5SM_get_info(H5F_t *f, unsigned *index_flags, size_t *list_to_btree,
               size_t *btree_to_list, hid_t dxpl_id)
 {
-    H5SM_master_table_t  *table = NULL;
-    unsigned i;
+    H5SM_master_table_t *table = NULL;
+    haddr_t table_addr;
+    uint8_t i;
     herr_t ret_value = SUCCEED;
     FUNC_ENTER_NOAPI(H5SM_get_info, FAIL)
 
+    HDassert(f);
+
+    /* Convenience variables */
+    table_addr = f->shared->sohm_addr;
+
     HDassert(table_addr != HADDR_UNDEF);
+    HDassert(f->shared->sohm_nindexes > 0);
+
+    /* Allocate and initialize the master table structure */
+    if(NULL == (table = H5MM_calloc(sizeof(H5SM_master_table_t))))
+	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+    table->version = f->shared->sohm_vers;
+    table->num_indexes = f->shared->sohm_nindexes;
 
-    /* Get the SOHM table from the cache */
-    if (NULL == (table = H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, table_addr, NULL, NULL, H5AC_READ)))
+    /* Read the rest of the SOHM table information from the cache */
+    if (NULL == (table = H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, table_addr, NULL, table, H5AC_READ)))
         HGOTO_ERROR(H5E_CACHE, H5E_CANTPROTECT, FAIL, "unable to load SOHM master table")
 
     /* Return info */
-    *nindexes = table->num_indexes;
     *list_to_btree = table->indexes[0].list_to_btree;
     *btree_to_list = table->indexes[0].btree_to_list;
 
diff --git a/src/H5SMbtree2.c b/src/H5SMbtree2.c
index 7e98b06..666ead7 100755
--- a/src/H5SMbtree2.c
+++ b/src/H5SMbtree2.c
@@ -43,6 +43,7 @@
 /* Local Prototypes */
 /********************/
 
+/* JAMES: name these as "H5SM_btree_store", etc? */
 static herr_t H5SM_message_store(void *native, const void *udata);
 static herr_t H5SM_message_retrieve(void *udata, const void *native);
 static herr_t H5SM_message_debug(FILE *stream, const H5F_t *f, hid_t dxpl_id,
@@ -207,7 +208,7 @@ H5SM_message_encode(const H5F_t *f, uint8_t *raw, const void *_nrecord)
 
     /* Encode the SOHM's fields */
     UINT32ENCODE(raw, message->hash);
-    UINT16ENCODE(raw, message->ref_count);
+    UINT32ENCODE(raw, message->ref_count);
     UINT64ENCODE(raw, message->fheap_id);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
@@ -227,6 +228,7 @@ H5SM_message_encode(const H5F_t *f, uint8_t *raw, const void *_nrecord)
  *
  *-------------------------------------------------------------------------
  */
+/* JAMES: can we combine this with H5SMcache functions? */
 herr_t
 H5SM_message_decode(const H5F_t *f, const uint8_t *raw, void *_nrecord)
 {
@@ -236,7 +238,7 @@ H5SM_message_decode(const H5F_t *f, const uint8_t *raw, void *_nrecord)
 
     /* Encode the SOHM's fields */
     UINT32DECODE(raw, message->hash);
-    UINT16DECODE(raw, message->ref_count);
+    UINT32DECODE(raw, message->ref_count);
     UINT64DECODE(raw, message->fheap_id);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
@@ -349,3 +351,46 @@ H5SM_decr_ref(void *record, void *op_data, hbool_t *changed)
 }
 
 
+
+/*-------------------------------------------------------------------------
+ * Function:	H5SM_convert_to_list_op
+ *
+ * Purpose:	An H5B2_remove_t callback function to convert a SOHM
+ *              B-tree index to a list.
+ *
+ *              Inserts this record into the list passed through op_data.
+ *
+ * Return:	Non-negative on success
+ *              Negative on failure
+ *
+ * Programmer:	James Laird
+ *              Monday, November 6, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5SM_convert_to_list_op(void * record, void *op_data)
+{
+    H5SM_sohm_t *message = (H5SM_sohm_t *) record;
+    H5SM_list_t *list = (H5SM_list_t *) op_data;
+    hsize_t      x;
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5SM_convert_to_list_op)
+
+    HDassert(record);
+    HDassert(op_data);
+
+    /* Insert this message into the list */
+    for(x=0; x<list->header->list_to_btree; x++)
+    {
+        if(list->messages[x].hash == H5O_HASH_UNDEF) /* JAMES: is this a valid test? */
+        {
+            HDmemcpy(&(list->messages[x]), message, sizeof(H5SM_sohm_t));
+            break;
+        }
+    }
+
+    /* Increment the number of messages in the list */
+    ++list->header->num_messages;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+}
\ No newline at end of file
diff --git a/src/H5SMcache.c b/src/H5SMcache.c
index 6403dc3..57c181b 100644
--- a/src/H5SMcache.c
+++ b/src/H5SMcache.c
@@ -47,6 +47,8 @@
 /* JAMES: should this change according to address size? */
 #define H5F_LISTBUF_SIZE  H5SM_LIST_SIZEOF_MAGIC + H5SM_MAX_LIST_ELEMS * 16
 
+#define H5SM_LIST_VERSION	0	/* Verion of Shared Object Header Message List Indexes */
+
 /******************/
 /* Local Typedefs */
 /******************/
@@ -55,7 +57,7 @@
 /* Local Prototypes */
 /********************/
 static herr_t H5SM_flush_table(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5SM_master_table_t *table);
-static H5SM_master_table_t *H5SM_load_table(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void *udata1, void *udata2);
+static H5SM_master_table_t *H5SM_load_table(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void *udata1, H5SM_master_table_t *table);
 static herr_t H5SM_clear_table(H5F_t *f, H5SM_master_table_t *table, hbool_t destroy);
 static herr_t H5SM_dest_table(H5F_t *f, H5SM_master_table_t* table);
 static herr_t H5SM_table_size(const H5F_t *f, const H5SM_master_table_t *table, size_t *size_ptr);
@@ -137,9 +139,7 @@ H5SM_flush_table(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5SM_ma
         HDmemcpy(p, H5SM_TABLE_MAGIC, (size_t)H5SM_TABLE_SIZEOF_MAGIC);
         p += H5SM_TABLE_SIZEOF_MAGIC;
 
-        *p++ = HDF5_SOHMTABLE_VERSION; /* Version */
-
-        *p++ = table->num_indexes; /* Number of indexes in the table */
+        *p++ = H5SM_MASTER_TABLE_VERSION; /* Version */
 
         /* Encode each index header */
         for(x=0; x<table->num_indexes; ++x) {
@@ -154,6 +154,8 @@ H5SM_flush_table(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5SM_ma
             H5F_addr_encode(f, &p, table->indexes[x].heap_addr); /* Address of the index's heap */
         }
 
+        /* JAMES: do checksum */
+
         /* Write the table to disk */
         HDassert((size_t)(p - buf) == size);
 	if(H5F_block_write(f, H5FD_MEM_SOHM, addr, size, dxpl_id, buf) < 0)
@@ -186,11 +188,9 @@ done:
  *-------------------------------------------------------------------------
  */
 static H5SM_master_table_t *
-H5SM_load_table(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED *udata1, void UNUSED *udata2)
+H5SM_load_table(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED *udata1, H5SM_master_table_t *table)
 {
-    H5SM_master_table_t *table;     /* The SOHM table being read in */
     size_t table_size;              /* Size of SOHM master table on disk */
-    size_t indexes_size;            /* Size of index headers on disk */
     uint8_t *buf=NULL;              /* Reading buffer */
     uint8_t *p;                     /* Pointer into input buffer */
     uint8_t x;                      /* Counter variable for index headers */
@@ -198,12 +198,13 @@ H5SM_load_table(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED *udata1
 
     FUNC_ENTER_NOAPI(H5SM_load_table, NULL)
 
-    /* Allocate space for the SOHM table data structure */
-    if(NULL == (table = H5MM_calloc(sizeof(H5SM_master_table_t))))
-	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+    HDassert(table);
+    HDassert(table->num_indexes > 0);
 
-    /* Compute the size of the SOHM table header on disk.  Read in just the table first */
-    table_size = H5SM_TABLE_SIZE(f);
+    /* Compute the size of the SOHM table header on disk.  This is the "table" itself
+     * plus each index within the table
+     */
+    table_size = H5SM_TABLE_SIZE(f) + (table->num_indexes * H5SM_INDEX_HEADER_SIZE(f));
 
     /* Allocate temporary buffer */
     if(NULL == (buf = HDmalloc(table_size)))
@@ -221,31 +222,19 @@ H5SM_load_table(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED *udata1
     p += H5SM_TABLE_SIZEOF_MAGIC;
 
     /* Version number */
-    if (HDF5_SOHMTABLE_VERSION != *p++)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unknown SOHM table version number")
-
-    table->num_indexes = *p++; /* Number of indexes in the table */
+    if (table->version != *p++)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "wrong SOHM table version number")
 
-    HDassert((size_t)(p - buf) == table_size);
+    /* Don't count the checksum in the table size yet, since it comes after
+     * all of the index headers
+     */
+    HDassert((size_t)(p - buf) == H5SM_TABLE_SIZE(f) /* JAMES: minus checksum size */);
 
-    /* Allocate space for the index headers */
+    /* Allocate space for the index headers in memory*/
     if(NULL == (table->indexes = H5FL_ARR_MALLOC(H5SM_index_header_t, table->num_indexes)))
 	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed for SOHM indexes")
 
-    /* Now read in the list of index headers */
-    indexes_size = table->num_indexes * H5SM_INDEX_HEADER_SIZE(f);
-
-    /* Re-allocate temporary buffer */
-    HDassert(buf);
-    HDfree(buf);
-    if(NULL == (buf = HDmalloc(indexes_size)))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
-
-
-    if(H5F_block_read(f, H5FD_MEM_SOHM, addr + table_size, indexes_size, dxpl_id, buf) < 0)
-	HGOTO_ERROR(H5E_SOHM, H5E_READERROR, NULL, "can't read SOHM table")
-    p=buf;
-
+    /* Read in the index headers */
     for(x=0; x<table->num_indexes; ++x) {
         table->indexes[x].index_type= *p++;  /* type of the index (list or B-tree) */
 
@@ -257,7 +246,9 @@ H5SM_load_table(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED *udata1
         H5F_addr_decode(f, &p, &(table->indexes[x].heap_addr));
     }
 
-    HDassert((size_t)(p - buf) == indexes_size);
+    /* Read in checksum */
+
+    HDassert((size_t)(p - buf) == table_size);
     ret_value = table;
 
 done:
@@ -406,6 +397,9 @@ H5SM_flush_list(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5SM_lis
         HDmemcpy(p, H5SM_LIST_MAGIC, (size_t)H5SM_LIST_SIZEOF_MAGIC);
         p += H5SM_LIST_SIZEOF_MAGIC;
 
+        /* Encode version */
+        *p++ = H5SM_LIST_VERSION;
+
         /* Write messages from the messages array to disk */
         /* JAMES: we have to search the whole array.  not the best way to do it; could go until we've written
          * num_messages */
@@ -413,7 +407,7 @@ H5SM_flush_list(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5SM_lis
             if(list->messages[x].fheap_id != 0 && list->messages[x].hash != H5O_HASH_UNDEF) {
               /* JAMES: use H5SM_message_encode here */
               UINT32ENCODE(p, list->messages[x].hash);  /* Read the hash value for this message */
-              UINT16ENCODE(p, list->messages[x].ref_count);  /* Read the reference count for this message */
+              UINT32ENCODE(p, list->messages[x].ref_count);  /* Read the reference count for this message */
               UINT64ENCODE(p, list->messages[x].fheap_id); /* Get the heap ID for the message */
             }
         }
@@ -492,11 +486,15 @@ H5SM_load_list(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED *udata1,
 	HGOTO_ERROR(H5E_SOHM, H5E_CANTLOAD, NULL, "bad SOHM list signature");
     p += H5SM_LIST_SIZEOF_MAGIC;
 
+    /* Check version JAMES: should be in master table, not list */
+    if (H5SM_LIST_VERSION != *p++)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "wrong shared message list version number")
+
     /* Read messages into the list array */
     for(x=0; x<header->num_messages; x++)
     {
         UINT32DECODE(p, list->messages[x].hash);  /* Read the hash value for this message */
-        UINT16DECODE(p, list->messages[x].ref_count);  /* Read the reference count for this message */
+        UINT32DECODE(p, list->messages[x].ref_count);  /* Read the reference count for this message */
         UINT64DECODE(p, list->messages[x].fheap_id); /* Get the heap ID for the message */
     }
 
diff --git a/src/H5SMpkg.h b/src/H5SMpkg.h
index 9016884..752ce84 100755
--- a/src/H5SMpkg.h
+++ b/src/H5SMpkg.h
@@ -36,13 +36,15 @@
 #define H5SM_TABLE_MAGIC "SMTB"
 #define H5SM_TABLE_SIZEOF_MAGIC 4
 
+#define H5SM_MASTER_TABLE_VERSION	0	/* Version of the Shared Object Header Message Master Table*/
+
 #define H5SM_SOHM_ENTRY_SIZE(f) (4  /* Hash value */                         \
-         + 2                      /* reference count*/                       \
+         + 4                      /* reference count*/                       \
          + 8)    /* JAMES: size of hash value on disk */
 
 #define H5SM_TABLE_SIZE(f) ( H5SM_TABLE_SIZEOF_MAGIC                         \
          + 1                                   /* Table version */           \
-         + 1)                                  /* Number of indexes */
+         + 0/* JAMES checksum */)                                  /* Checksum */
 
 #define H5SM_INDEX_HEADER_SIZE(f) (1 /* Whether index is a list or B-tree */ \
          + 2         /* Type of messages stored in the index */              \
@@ -50,7 +52,9 @@
          + H5F_SIZEOF_ADDR(f) /* Location of list or B-tree */               \
          + H5F_SIZEOF_ADDR(f)) /* Address of heap */
 
+/* JAMES: add checksum? */
 #define H5SM_LIST_SIZE(f, num_mesg) H5SM_LIST_SIZEOF_MAGIC                   \
+         + 1        /* List version */                                       \
          + (H5SM_SOHM_ENTRY_SIZE(f) * num_mesg)
 
 #define H5SM_MAX_INDEXES 8
@@ -134,8 +138,9 @@ typedef struct {
     /* Information for H5AC cache functions, _must_ be first field in structure */
     H5AC_info_t cache_info;
 
-    uint8_t num_indexes;      /* Number of indexes */
-    H5SM_index_header_t *indexes;  /* Array of num_indexes indexes */
+    unsigned version;               /* Version of the table struct */
+    uint8_t num_indexes;            /* Number of indexes */
+    H5SM_index_header_t *indexes;   /* Array of num_indexes indexes */
 } H5SM_master_table_t;
 
 
@@ -170,5 +175,8 @@ H5_DLL herr_t H5SM_message_compare(const H5SM_mesg_key_t *rec1,
 /* H5B2_modify_t callbacks to adjust record's refcount. */
 H5_DLL herr_t H5SM_incr_ref(void *record, void *op_data, hbool_t *changed);
 H5_DLL herr_t H5SM_decr_ref(void *record, void *op_data, hbool_t *changed);
-#endif /*_H5SMpkg_H*/
 
+/* H5B2_remove_t callback to add messages to a list index */
+H5_DLL herr_t H5SM_convert_to_list_op(void * record, void *op_data);
+
+#endif /*_H5SMpkg_H*/
diff --git a/src/H5SMprivate.h b/src/H5SMprivate.h
index f1c2ad5..5d75213 100755
--- a/src/H5SMprivate.h
+++ b/src/H5SMprivate.h
@@ -22,7 +22,6 @@
 #ifndef _H5SMprivate_H
 #define _H5SMprivate_H
 
-#include "H5SMpublic.h"
 #include "H5Oprivate.h"
 #include "H5Pprivate.h"
 
@@ -30,9 +29,6 @@
 /* Library Private Typedefs */
 /****************************/
 
-#define HDF5_SOHMTABLE_VERSION	0	/* Version of the Shared Object Header Message Master Table*/
-#define HDF5_SOHMINDEX_VERSION	0	/* Verion of Shared Object Header Message Indexes */
-
 #define H5SM_MAX_NUM_INDEXES 6
 
 /* Typedef for a SOHM index node */
@@ -50,9 +46,8 @@ H5_DLL herr_t H5SM_init(H5F_t *f, H5P_genplist_t *fc_plist, hid_t dxpl_id);
 H5_DLL htri_t H5SM_try_share(H5F_t *f, hid_t dxpl_id, unsigned type_id,
                   void *mesg);
 H5_DLL herr_t H5SM_try_delete(H5F_t *f, hid_t dxpl_id, unsigned type_id, const H5O_shared_t *mesg);
-H5_DLL herr_t H5SM_get_info(H5F_t *f, haddr_t table_addr, unsigned *nindexes,
-              unsigned *index_flags, size_t *list_to_btree,
-              size_t *btree_to_list, hid_t dxpl_id);
+H5_DLL herr_t H5SM_get_info(H5F_t *f, unsigned *index_flags,
+                  size_t *list_to_btree, size_t *btree_to_list, hid_t dxpl_id);
 H5_DLL haddr_t H5SM_get_fheap_addr(H5F_t *f, unsigned type_id, hid_t dxpl_id);
 
 #endif /*_H5SMprivate_H*/
diff --git a/src/H5SMpublic.h b/src/H5SMpublic.h
index c1531f7..4f7f074 100755
--- a/src/H5SMpublic.h
+++ b/src/H5SMpublic.h
@@ -22,21 +22,5 @@
 #ifndef _H5SMpublic_H
 #define _H5SMpublic_H
 
-/* Flags indicating which kinds of object header messages a given SOHM index
- * holds.
- * Pass these flags in using the mesg_type_flags array in
- * H5P_set_shared_mesgs.
- * (Developers: These flags correspond to object header message type_ids,
- * but we need to assign each kind of message to a different bit so that
- * one index can hold multiple types.)
- */
-#define H5SM_NONE_FLAG     0x0000          /* No shared messages */
-#define H5SM_SDSPACE_FLAG  0x0001          /* Simple Dataspace Message.  */
-#define H5SM_DTYPE_FLAG	   0x0002          /* Datatype Message.  */
-#define H5SM_FILL_FLAG     0x0004          /* Fill Value Message. */
-#define H5SM_PLINE_FLAG	   0x0008          /* Filter pipeline message.  */
-#define H5SM_ATTR_FLAG	   0x0010          /* Attribute Message.  */
-#define H5SM_ALL_FLAG      (H5SM_SDSPACE_FLAG | H5SM_DTYPE_FLAG | H5SM_FILL_FLAG | H5SM_PLINE_FLAG | H5SM_ATTR_FLAG)
-
 #endif /*_H5SMpublic_H*/
 
diff --git a/src/hdf5.h b/src/hdf5.h
index 0b973f9..a3ae138 100644
--- a/src/hdf5.h
+++ b/src/hdf5.h
@@ -35,7 +35,6 @@
 #include "H5Ppublic.h"		/* Property lists			*/
 #include "H5Rpublic.h"		/* References				*/
 #include "H5Spublic.h"		/* Dataspaces				*/
-#include "H5SMpublic.h"		/* Shared Object Header Messages	*/
 #include "H5Tpublic.h"		/* Datatypes				*/
 #include "H5Zpublic.h"		/* Data filters				*/