[svn-r1925] DPSS is checked in.

8 files changed, 693 insertions, 3 deletions

diff --git a/src/H5F.c b/src/H5F.c
index cb067b3..10df2cd 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -25,6 +25,7 @@ static char		RcsId[] = "@(#)$Revision$";
 #include <H5FDfamily.h>		/*family of files			  */
 #include <H5FDmpio.h>		/*MPI-2 I/O				  */
 #include <H5FDgass.h>       /*GASS I/O                                */
+#include <H5FDdpss.h>           /*DPSS I/O                                */
 #include <H5FDmulti.h>		/*multiple files partitioned by mem usage */
 #include <H5FDsec2.h>		/*Posix unbuffered I/O			*/
 #include <H5FDstdio.h>		/* Standard C buffered I/O		*/
@@ -95,6 +96,10 @@ H5F_xfer_t	H5F_xfer_dflt = {
     NULL,                   	/*No information needed for free() calls    */
     -2,				/*See H5Pget_driver()			    */
     NULL,			/*No file driver-specific information yet   */
+#ifdef COALESCE_READS
+    0,                          /*coalesce single reads into a read         */
+                                /*transaction                               */
+#endif
 };
 
 /*
@@ -209,6 +214,9 @@ H5F_init_interface(void)
 #ifdef H5_HAVE_GASS
 	if ((status=H5FD_GASS)<0) goto end_registration;
 #endif
+#ifdef HAVE_DPSS
+	if ((status=H5FD_DPSS)<0) goto end_registration;
+#endif
 	if ((status=H5FD_CORE)<0) goto end_registration;
 	if ((status=H5FD_MULTI)<0) goto end_registration;
 #ifdef H5_HAVE_PARALLEL
diff --git a/src/H5FDdpss.c b/src/H5FDdpss.c
new file mode 100644
index 0000000..576d5d4
--- /dev/null
+++ b/src/H5FDdpss.c
@@ -0,0 +1,627 @@
+/*
+ * Copyright © 1999 NCSA
+ *                  All rights reserved.
+ *
+ * Programmer:  Thomas Radke <tradke@aei-potsdam.mpg.de>
+ *              Monday, October 11, 1999
+ *
+ * Purpose:     This is the Distributed Parallel Storage System I/O driver.
+ *
+ */
+
+#include <hdf5.h>
+#include <H5Eprivate.h>         /* error handling    */
+#include <H5MMprivate.h>        /* memory management */
+
+/*** FIXME: should this be included here or in <hdf5.h> ??? ***/
+#include "H5FDdpss.h"
+
+#ifdef COALESCE_READS
+/* Packages needed by this file.*/
+#include <H5Fprivate.h>
+#include <H5Iprivate.h>
+#endif
+
+
+/* uncomment this to get some debugging output from this driver */
+#if 1
+#define DEBUG 1
+#endif
+
+/* The driver identification number, initialized at runtime */
+static hid_t H5FD_DPSS_g = 0;
+
+
+/* compile this only if HDF5 was configured to use the DPSS I/O driver */
+#ifdef H5_HAVE_DPSS
+
+/* include the DPSS Storage Client header */
+#include <grid_storage_file.h>
+
+/*
+ * The description of a file belonging to this driver. The `eoa' and `eof'
+ * determine the amount of hdf5 address space in use and the high-water mark
+ * of the file (the current size of the underlying Unix file).
+ * When opening a file the `eof' will be set to the current file size,
+ * `eoa' will be set * to zero.
+ */
+typedef struct H5FD_dpss_t {
+    H5FD_t                pub;            /* public stuff, must be first    */
+    grid_storage_handle_t handle;         /* the DPSS file handle           */
+    haddr_t               eoa;            /* end of allocated region        */
+    haddr_t               eof;            /* end of file; current file size */
+} H5FD_dpss_t;
+
+
+/*** FIXME: is this really needed here ? ***/
+/*
+ * This driver supports systems that have the lseek64() function by defining
+ * some macros here so we don't have to have conditional compilations later
+ * throughout the code.
+ *
+ * file_offset_t:       The datatype for file offsets, the second argument of
+ *                      the lseek() or lseek64() call.
+ *
+ * file_seek:           The function which adjusts the current file position,
+ *                      either lseek() or lseek64().
+ */
+#ifdef HAVE_LSEEK64
+#   define file_offset_t        off64_t
+#   define file_seek            lseek64
+#else
+#   define file_offset_t        off_t
+#   define file_seek            lseek
+#endif
+
+/*
+ * These macros check for overflow of various quantities.  These macros
+ * assume that file_offset_t is signed and haddr_t and size_t are unsigned.
+ * 
+ * ADDR_OVERFLOW:    Checks whether a file address of type `haddr_t'
+ *            is too large to be represented by the second argument
+ *            of the file seek function.
+ *
+ * SIZE_OVERFLOW:    Checks whether a buffer size of type `hsize_t' is too
+ *            large to be represented by the `size_t' type.
+ *
+ * REGION_OVERFLOW:    Checks whether an address and size pair describe data
+ *            which can be addressed entirely by the second
+ *            argument of the file seek function.
+ */
+#define MAXADDR (((haddr_t)1<<(8*sizeof(file_offset_t)-1))-1)
+#define ADDR_OVERFLOW(A)    (HADDR_UNDEF==(A) ||                  \
+                 ((A) & ~(haddr_t)MAXADDR))
+#define SIZE_OVERFLOW(Z)    ((Z) & ~(hsize_t)MAXADDR)
+#define REGION_OVERFLOW(A,Z)    (ADDR_OVERFLOW(A) || SIZE_OVERFLOW(Z) ||      \
+                 sizeof(file_offset_t)<sizeof(size_t) ||      \
+                                 HADDR_UNDEF==(A)+(Z) ||              \
+                 (file_offset_t)((A)+(Z))<(file_offset_t)(A))
+
+#define PRINT_GLOBUS_ERROR_MSG(globus_result)                                 \
+        {                                                                     \
+            char *globus_error_msg;                                           \
+                                                                              \
+            globus_error_msg = globus_object_printable_to_string (            \
+                                   globus_error_get (globus_result));         \
+            if (globus_error_msg) {                                           \
+                /*** FIXME: put appropriate minor error code in here ***/     \
+                HERROR (H5E_IO, -1, globus_error_msg);                        \
+                globus_free (globus_error_msg);                               \
+            }                                                                 \
+        }
+
+/* DPSS driver function prototypes */
+static H5FD_t *H5FD_dpss_open (const char *name, unsigned flags,
+                               hid_t UNUSED fapl_id, haddr_t maxaddr);
+static herr_t H5FD_dpss_close (H5FD_t *_file);
+static haddr_t H5FD_dpss_get_eoa (H5FD_t *_file);
+static herr_t H5FD_dpss_set_eoa (H5FD_t *_file, haddr_t addr);
+static haddr_t H5FD_dpss_get_eof (H5FD_t *_file);
+static herr_t H5FD_dpss_read (H5FD_t *_file, hid_t fapl_id, haddr_t addr,
+                              hsize_t size, void *buf);
+static herr_t H5FD_dpss_write (H5FD_t *_file, hid_t UNUSED fapl_id,haddr_t addr,
+                               hsize_t size, const void *buf);
+
+/* The DPSS I/O driver information */
+static const H5FD_class_t H5FD_dpss_g = {
+    "dpss",                                        /* name           */
+    MAXADDR,                                       /* maxaddr        */
+    NULL,                                          /* sb_size        */
+    NULL,                                          /* sb_encode      */
+    NULL,                                          /* sb_decode      */
+    0,                                             /* fapl_size      */
+    NULL,                                          /* fapl_get       */
+    NULL,                                          /* fapl_copy      */
+    NULL,                                          /* fapl_free      */
+    0,                                             /* dxpl_size      */
+    NULL,                                          /* dxpl_copy      */
+    NULL,                                          /* dxpl_free      */
+    H5FD_dpss_open,                                /* open           */
+    H5FD_dpss_close,                               /* close          */
+    NULL,                                          /*  cmp           */
+    NULL,                                          /* alloc          */
+    NULL,                                          /* free           */
+    H5FD_dpss_get_eoa,                             /* get_eoa        */
+    H5FD_dpss_set_eoa,                             /* set_eoa        */
+    H5FD_dpss_get_eof,                             /* get_eof        */
+    H5FD_dpss_read,                                /* read           */
+    H5FD_dpss_write,                               /* write          */
+    NULL,                                          /* flush          */
+    H5FD_FLMAP_SINGLE,                             /* fl_map         */
+};
+
+/* Interface initialization */
+#define PABLO_MASK      H5FD_dpss_mask
+#define INTERFACE_INIT  H5FD_dpss_init
+static intn interface_initialize_g = 0;
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD_dpss_init
+ *
+ * Purpose:     Initialize this driver by registering the driver with the
+ *              library.
+ *
+ * Return:      Success:    The driver ID for the DPSS driver.
+ *
+ *              Failure:    Negative.
+ *
+ * Programmer:  Thomas Radke
+ *              Monday, October 11, 1999
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+H5FD_dpss_init (void)
+{
+    int globus_result;           /* NOTE: globus_module_activate() doesn't
+                                          return a globus_result_t type */
+
+    FUNC_ENTER (H5FD_dpss_init, FAIL);
+
+    /* register the DPSS driver if it wasn't already */
+    if (! H5FD_DPSS_g)
+        H5FD_DPSS_g = H5FDregister (&H5FD_dpss_g);
+
+    /* active the DPSS storage client module which in turn activates
+       all other Globus modules that are needed */
+    if (H5FD_DPSS_g >= 0) {
+        globus_result = globus_module_activate (GRID_STORAGE_FILE_MODULE);
+        if (GLOBUS_SUCCESS != globus_result) {
+            H5FDunregister (H5FD_DPSS_g);
+            H5FD_DPSS_g = -1;
+            HRETURN_ERROR (H5E_IO, H5E_CANTINIT, FAIL,
+                           "Cannot activate Globus Grid Storage File module");
+        }
+    }
+
+    FUNC_LEAVE (H5FD_DPSS_g);
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Pset_fapl_dpss
+ *
+ * Purpose:     Modify the file application list to use the DPSS I/O
+ *              driver defined in this source file.
+ *
+ * Return:      Success:    Non-negative
+ *
+ *              Failure:    Negative
+ *
+ * Programmer:  Thomas Radke
+ *              Monday, October 11, 1999
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_fapl_dpss (hid_t fapl_id)
+{
+    herr_t ret_value=FAIL;
+
+    FUNC_ENTER (H5FD_set_fapl_dpss, FAIL);
+
+    /* Check arguments */
+    if (H5P_FILE_ACCESS != H5Pget_class (fapl_id))
+        HRETURN_ERROR (H5E_PLIST, H5E_BADTYPE, FAIL, "not a fapl");
+
+    ret_value = H5Pset_driver (fapl_id, H5FD_DPSS, NULL);
+
+    FUNC_LEAVE (ret_value);
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD_dpss_open
+ *
+ * Purpose:     Creates/opens a DPSS file instance identified by its URL
+ *              as an HDF5 file.
+ *
+ * Return:      Success:    A pointer to a new file data structure. The
+ *                          public fields will be initialized by the
+ *                          caller, which is always H5FD_open().
+ *
+ *              Failure:    NULL
+ *
+ * Programmer:  Thomas Radke
+ *              Monday, October 11, 1999
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static H5FD_t *
+H5FD_dpss_open (const char *name, unsigned flags, hid_t UNUSED fapl_id,
+                haddr_t maxaddr)
+{
+    int                      i;
+    globus_result_t          globus_result;
+    grid_storage_url_t       *url = (grid_storage_url_t *) name;
+    grid_storage_handle_t    handle;
+    H5FD_dpss_t              *file;
+    unsigned int             o_flags;
+    char                     int_attribute_value [10];
+    int64_t                  file_size;
+    char                     **property_names,
+                             **property_values;
+    grid_storage_attribute_t attributes = GRID_STORAGE_ATTRIBUTE_INITIALIZER;
+
+
+    FUNC_ENTER (H5FD_dpss_open, NULL);
+
+#ifdef DEBUG
+    fprintf (stdout, "H5FD_dpss_open: name='%s', flags=0x%x\n", name, flags);
+#endif
+
+    /* Check arguments */
+    if (!name || !*name)
+        HRETURN_ERROR (H5E_ARGS, H5E_BADVALUE, NULL, "invalid file name");
+    if (0==maxaddr || HADDR_UNDEF==maxaddr)
+        HRETURN_ERROR (H5E_ARGS, H5E_BADRANGE, NULL, "bogus maxaddr");
+    if (ADDR_OVERFLOW (maxaddr))
+        HRETURN_ERROR (H5E_ARGS, H5E_BADRANGE, NULL, "bogus maxaddr");
+
+    /* Build the open flags */
+    o_flags = (H5F_ACC_RDWR & flags) ? O_RDWR : O_RDONLY;
+    if (H5F_ACC_TRUNC & flags) o_flags |= O_TRUNC;
+    if (H5F_ACC_CREAT & flags) o_flags |= O_CREAT;
+    if (H5F_ACC_EXCL  & flags) o_flags |= O_EXCL;
+    sprintf (int_attribute_value, "%d", o_flags);
+
+    /* set the 'open flags' attribute */
+    globus_result =
+        grid_storage_add_attribute (GRID_STORAGE_ATTRIBUTE_OPEN_FLAGS,
+                                    int_attribute_value, &attributes);
+    if (GLOBUS_SUCCESS != globus_result) {
+        PRINT_GLOBUS_ERROR_MSG (globus_result);
+        HRETURN_ERROR (H5E_IO, H5E_CANTOPENFILE, NULL,
+                       "Can't set attributes for file instance");
+    }
+
+    /* open the file instance */
+    globus_result = grid_storage_open ((grid_storage_url_t *) url, &handle,
+                                       &attributes);
+    if (GLOBUS_SUCCESS != globus_result) {
+        PRINT_GLOBUS_ERROR_MSG (globus_result);
+        HRETURN_ERROR (H5E_IO, H5E_CANTOPENFILE, NULL,
+                       "Can't open file instance");
+    }
+
+    /* Get the size of the file instance.
+       Read all the instance properties ... */
+    globus_result = grid_storage_list_properties (url, NULL, &property_names,
+                                                  &property_values);
+    if (GLOBUS_SUCCESS != globus_result) {
+        PRINT_GLOBUS_ERROR_MSG (globus_result);
+        grid_storage_close (&handle, NULL);
+        HRETURN_ERROR (H5E_IO, H5E_CANTOPENFILE, NULL,
+                       "Can't get properties of file instance");
+    }
+    /* ... now sort out the 'size' property */
+    file_size = -1;
+    for (i = 0; property_names [i]; i++) {
+        if (strcmp (property_names [i], GRID_STORAGE_PROPERTY_SIZE) == 0) {
+            if (property_values [i])
+                sscanf (property_values [i], "%"PRINTF_LL_WIDTH"u", &file_size);
+        }
+        /* don't forget to free the allocated property strings */
+        globus_libc_free (property_names [i]);
+        globus_libc_free (property_values [i]);
+    }
+    globus_libc_free (property_names);
+    globus_libc_free (property_values);
+
+    /* Did we find a size ? */
+    if (file_size < 0) {
+        grid_storage_close (&handle, NULL);
+        HRETURN_ERROR (H5E_IO, H5E_CANTOPENFILE, NULL,
+                       "Can't get size of file instance");
+    }
+
+    /* Create the new file struct */
+    if (NULL == (file = (H5FD_dpss_t *) H5MM_calloc (sizeof (H5FD_dpss_t))))
+        HRETURN_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL,
+                       "Can't allocate file struct");
+    file->handle = handle;
+    file->eof = (haddr_t) file_size;
+
+    FUNC_LEAVE ((H5FD_t *) file);
+}
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD_dpss_close
+*
+ * Purpose:     Closes a previously opened DPSS file instance.
+ *
+ * Return:      Success:    0
+ *
+ *              Failure:    -1, file not closed.
+ *
+ * Programmer:  Thomas Radke
+ *              Monday, October 11, 1999
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_dpss_close (H5FD_t *_file)
+{
+    globus_result_t globus_result;
+    H5FD_dpss_t *file = (H5FD_dpss_t *) _file;
+
+    FUNC_ENTER (H5FD_dpss_close, FAIL);
+
+    if (NULL == file)
+      HRETURN_ERROR (H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file handle");
+    
+    globus_result = grid_storage_close (&file->handle, NULL);
+    if (GLOBUS_SUCCESS != globus_result) {
+        PRINT_GLOBUS_ERROR_MSG (globus_result);
+        HRETURN_ERROR (H5E_IO, H5E_CANTCLOSEFILE, FAIL, "Failed to close file instance");
+    }
+
+    H5MM_xfree (file);
+
+    FUNC_LEAVE (SUCCEED);
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD_dpss_get_eoa
+ *
+ * Purpose:     Gets the end-of-address marker for the file. The EOA marker
+ *              is the first address past the last byte allocated in the
+ *              format address space.
+ *
+ * Return:      Success:    The end-of-address marker.
+ *
+ * Programmer:  Thomas Radke
+ *              Monday, October 11, 1999
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static haddr_t
+H5FD_dpss_get_eoa (H5FD_t *_file)
+{
+    H5FD_dpss_t *file = (H5FD_dpss_t *) _file;
+
+    FUNC_ENTER (H5FD_dpss_get_eoa, HADDR_UNDEF);
+
+    FUNC_LEAVE (file->eoa);
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD_dpss_set_eoa
+ *
+ * Purpose:     Set the end-of-address marker for the file. This function is
+ *              called shortly after an existing HDF5 file is opened in order
+ *              to tell the driver where the end of the HDF5 data is located.
+ *
+ * Return:      Success:        0
+ *
+ * Programmer:  Thomas Radke
+ *              Monday, October 11, 1999
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_dpss_set_eoa (H5FD_t *_file, haddr_t addr)
+{
+    H5FD_dpss_t *file = (H5FD_dpss_t *) _file;
+
+    FUNC_ENTER (H5FD_dpss_set_eoa, FAIL);
+
+    file->eoa = addr;
+
+    FUNC_LEAVE (SUCCEED);
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD_dpss_get_eof
+ *
+ * Purpose:     Returns the end-of-file marker, which is the greater of
+ *              either the Unix end-of-file or the HDF5 end-of-address
+ *              markers.
+ *
+ * Return:      Success:        End of file address, the first address past
+ *                              the end of the "file", either the DPSS
+ *                              file or the HDF5 file.
+ *
+ * Programmer:  Thomas Radke
+ *              Monday, October 11, 1999
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static haddr_t
+H5FD_dpss_get_eof (H5FD_t *_file)
+{
+    H5FD_dpss_t *file = (H5FD_dpss_t*) _file;
+
+    FUNC_ENTER (H5FD_dpss_get_eof, HADDR_UNDEF);
+
+    FUNC_LEAVE (file->eof > file->eoa ? file->eof : file->eoa);
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD_dpss_read
+ *
+ * Purpose:     Reads SIZE bytes of data from FILE beginning at address ADDR
+ *              into buffer BUF.
+ *
+ * Return:      Success:        Zero. Result is stored in caller-supplied
+ *                              buffer BUF.
+ *
+ *              Failure:        -1, Contents of buffer BUF are undefined.
+ *
+ * Programmer:  Thomas Radke
+ *              Monday, October 11, 1999
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_dpss_read (H5FD_t *_file, hid_t dxpl_id, haddr_t addr,
+                hsize_t size, void *buf/*out*/)
+{
+    H5FD_dpss_t *file = (H5FD_dpss_t *) _file;
+    globus_result_t  globus_result;
+#ifdef COALESCE_READS
+    static int count = 0;                 /* counter for single reads */
+    H5F_xfer_t *xfer_parms;               /*transfer property list*/
+#endif
+
+    FUNC_ENTER (H5FD_dpss_read, FAIL);
+
+#ifdef DEBUG
+    fprintf (stdout, "H5FD_dpss_read: addr 0x%lx, size %ld\n",
+             (unsigned long int) addr, (unsigned long int) size);
+#endif
+
+    /* Check parameters */
+    if (! file)
+        HRETURN_ERROR (H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file handle");
+    if (! buf)
+        HRETURN_ERROR (H5E_ARGS, H5E_BADVALUE, FAIL, "invalid buffer pointer");
+
+    /* Check for overflow conditions */
+    if (HADDR_UNDEF == addr)
+        HRETURN_ERROR (H5E_ARGS, H5E_BADRANGE, FAIL, "addr undefined");
+    if (REGION_OVERFLOW (addr, size))
+        HRETURN_ERROR (H5E_ARGS, H5E_OVERFLOW, FAIL, "addr too large");
+    if (addr + size > file->eoa)
+        HRETURN_ERROR (H5E_ARGS, H5E_OVERFLOW, FAIL, "addr too large");
+
+#ifdef COALESCE_READS
+    /* Get the dataset transfer property list */
+    if (H5P_DEFAULT == dxpl_id) {
+        xfer_parms = &H5F_xfer_dflt;
+    } else if (H5P_DATA_XFER != H5P_get_class (dxpl_id) ||
+               NULL == (xfer_parms = H5I_object (dxpl_id))) {
+        HRETURN_ERROR (H5E_PLIST, H5E_BADTYPE, FAIL, "not a xfer");
+    }
+
+    if (xfer_parms->gather_reads) {
+        if (! count)
+            count = xfer_parms->gather_reads;
+#ifdef DEBUG
+        fprintf (stdout, "H5FD_dpss_read: request would be queued\n");
+#endif
+    } else {
+#ifdef DEBUG
+        fprintf (stdout, "H5FD_dpss_read: transaction would be performed "
+                         "with %d individual reads\n", count + 1);
+#endif
+        count = 0;
+    }
+#endif
+
+    /* do the (synchronuous) write operation */
+    globus_result = grid_storage_read (&file->handle, (unsigned char *) buf,
+                                       (size_t) addr, (size_t) size, NULL);
+    if (GLOBUS_SUCCESS != globus_result) {
+        PRINT_GLOBUS_ERROR_MSG (globus_result);
+        HRETURN_ERROR (H5E_IO, H5E_READERROR, FAIL,
+                       "Failed to read file instance");
+    }
+
+    FUNC_LEAVE (SUCCEED);
+}
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD_dpss_write
+ *
+ * Purpose:     Writes SIZE bytes of data to FILE beginning at address ADDR
+ *              from buffer BUF.
+ *
+ * Return:      Success:        Zero
+ *
+ *              Failure:        -1
+ *
+ * Programmer:  Thomas Radke
+ *              Monday, October 11, 1999
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_dpss_write (H5FD_t *_file, hid_t UNUSED dxpl_id, haddr_t addr,
+                 hsize_t size, const void *buf)
+{
+    H5FD_dpss_t  *file = (H5FD_dpss_t *) _file;
+    globus_result_t  globus_result;
+
+    FUNC_ENTER (H5FD_dpss_write, FAIL);
+
+#ifdef DEBUG
+    fprintf (stdout, "H5FD_dpss_write: addr 0x%lx, size %ld\n",
+             (unsigned long int) addr, (unsigned long int) size);
+#endif
+
+    /* Check parameters */
+    if (! file)
+        HRETURN_ERROR (H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file handle");
+    if (! buf)
+        HRETURN_ERROR (H5E_ARGS, H5E_BADVALUE, FAIL, "invalid buffer pointer");
+
+    /* Check for overflow conditions */
+    if (HADDR_UNDEF == addr)
+        HRETURN_ERROR (H5E_ARGS, H5E_BADRANGE, FAIL, "addr undefined");
+    if (REGION_OVERFLOW (addr, size))
+        HRETURN_ERROR (H5E_ARGS, H5E_OVERFLOW, FAIL, "addr too large");
+    if (addr + size > file->eoa)
+        HRETURN_ERROR (H5E_ARGS, H5E_OVERFLOW, FAIL, "addr too large");
+
+    /* do the (synchronuous) write operation */
+    globus_result = grid_storage_write (&file->handle, (unsigned char *) buf,
+                                        (size_t) addr, (size_t) size, NULL);
+    if (GLOBUS_SUCCESS != globus_result) {
+        PRINT_GLOBUS_ERROR_MSG (globus_result);
+        HRETURN_ERROR (H5E_IO, H5E_WRITEERROR, FAIL,
+                       "Failed to write file instance");
+    }
+
+    /* expand end-of-file marker if necessary */
+    if (addr > file->eof)
+        file->eof = addr;
+
+    FUNC_LEAVE (SUCCEED);
+}
+
+#endif /* DPSS */
+  
diff --git a/src/H5FDdpss.h b/src/H5FDdpss.h
new file mode 100644
index 0000000..7ba8ca2
--- /dev/null
+++ b/src/H5FDdpss.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright © 1999 NCSA
+ *                  All rights reserved.
+ *
+ * Programmer:  Thomas Radke <tradke@aei-potsdam.mpg.de>
+ *              Monday, October 11, 1999
+ *
+ * Purpose:	The public header file for the DPSS driver.
+ */
+#ifndef H5FDdpss_H
+#define H5FDdpss_H
+
+#include <H5public.h>          /* typedef for herr_t */
+#include <H5Ipublic.h>         /* typedef for hid_t  */
+
+#ifdef H5_HAVE_DPSS 
+#define H5FD_DPSS              (H5FD_dpss_init())
+#else
+#define H5FD_DPSS              (-1)
+#endif   
+
+/* Function prototypes */
+#ifdef H5_HAVE_DPSS
+
+hid_t H5FD_dpss_init(void);
+herr_t H5Pset_fapl_dpss (hid_t fapl_id);
+herr_t H5Pget_fapl_dpss (hid_t fapl_id);
+
+#endif
+
+#endif /* H5FDdpss_H */
+  
diff --git a/src/H5FDgass.c b/src/H5FDgass.c
index 911053d..bafbd2e 100644
--- a/src/H5FDgass.c
+++ b/src/H5FDgass.c
@@ -355,7 +355,6 @@ H5FD_gass_open(const char *name, unsigned flags, hid_t fapl_id,
     if ((flags & H5F_ACC_CREAT) && (flags & H5F_ACC_RDWR) && (flags & H5F_ACC_EXCL)) {
       if ((fd = globus_gass_open (filename, O_RDWR|O_TRUNC)) < 0)
         HRETURN_ERROR(H5E_IO, H5E_CANTOPENFILE, NULL, "open failed");
-      
     }
     else if ((flags & H5F_ACC_CREAT) && (flags & H5F_ACC_RDWR) && (flags & H5F_ACC_TRUNC)) {
       if ((fd = globus_gass_open (filename, O_RDWR|O_TRUNC)) < 0)
diff --git a/src/H5Farray.c b/src/H5Farray.c
index 02a39d3..f2b79f1 100644
--- a/src/H5Farray.c
+++ b/src/H5Farray.c
@@ -143,6 +143,9 @@ H5F_arr_read(H5F_t *f, hid_t dxpl_id, const struct H5O_layout_t *layout,
 #ifdef H5_HAVE_PARALLEL
     H5FD_mpio_xfer_t xfer_mode=H5FD_MPIO_INDEPENDENT;
 #endif
+#ifdef COALESCE_READS
+    H5F_xfer_t *xfer_parms;                     /*transfer property list*/
+#endif
    
     FUNC_ENTER(H5F_arr_read, FAIL);
 
@@ -270,7 +273,21 @@ H5F_arr_read(H5F_t *f, hid_t dxpl_id, const struct H5O_layout_t *layout,
 	}
 #endif
 
+#ifdef COALESCE_READS
+        /* Get the dataset transfer property list */
+        if (H5P_DEFAULT == dxpl_id) {
+            xfer_parms = &H5F_xfer_dflt;
+        } else if (H5P_DATA_XFER != H5P_get_class (dxpl_id) ||
+               NULL == (xfer_parms = H5I_object (dxpl_id))) {
+            HRETURN_ERROR (H5E_ARGS, H5E_BADTYPE, FAIL, "not xfer parms");
+        }
+
+	for (z=0, xfer_parms->gather_reads = nelmts - 1;
+             z<nelmts;
+             z++, xfer_parms->gather_reads--) {
+#else
 	for (z=0; z<nelmts; z++) {
+#endif
 
 	    /* Read from file */
 	    if (efl && efl->nused>0) {
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index ad4e1cf..fff050b 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -274,6 +274,10 @@ typedef struct H5F_xfer_t {
     void		*free_info;	/*VL datatype free information	     */
     hid_t		driver_id;	/*File driver ID		     */
     void		*driver_info;	/*File driver specific information   */
+#ifdef COALESCE_READS
+    uintn               gather_reads;   /*coalesce single reads into a read  */
+                                        /*transaction                        */
+#endif
 } H5F_xfer_t;
 
 /* The raw data chunk cache */
diff --git a/src/H5config.h.in b/src/H5config.h.in
index bf00559..8078e26 100644
--- a/src/H5config.h.in
+++ b/src/H5config.h.in
@@ -77,6 +77,9 @@
 /* Define if we have Globus GASS support */
 #undef HAVE_GASS
 
+/* Define if we have Globus DPSS support */
+#undef HAVE_DPSS
+
 /* The number of bytes in a __int64.  */
 #undef SIZEOF___INT64
 
diff --git a/src/Makefile.in b/src/Makefile.in
index 20bd313..cdef845 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -26,7 +26,7 @@ LIB_SRC=H5.c H5A.c H5AC.c H5B.c H5D.c H5E.c H5F.c H5Farray.c H5Fistore.c \
     H5Oefl.c H5Ofill.c H5Olayout.c H5Omtime.c H5Oname.c H5Onull.c \
     H5Osdspace.c H5Oshared.c H5Ostab.c H5P.c H5R.c H5RA.c H5S.c H5Sall.c \
     H5Shyper.c H5Smpio.c H5Snone.c H5Spoint.c H5Sselect.c H5T.c H5Tbit.c \
-    H5Tconv.c H5Tinit.c H5Tvlen.c H5TB.c H5V.c H5Z.c H5Zdeflate.c
+    H5Tconv.c H5Tinit.c H5Tvlen.c H5TB.c H5V.c H5Z.c H5Zdeflate.c H5FDdpss.c
 
 LIB_OBJ=$(LIB_SRC:.c=.lo)
 
@@ -39,7 +39,7 @@ PUB_HDR=H5public.h H5Apublic.h H5ACpublic.h H5Bpublic.h H5Dpublic.h \
     H5FDsec2.h H5FDcore.h H5FDmulti.h H5FDstdio.h H5Gpublic.h H5HGpublic.h \
     H5HLpublic.h H5Ipublic.h H5MMpublic.h H5Opublic.h H5Ppublic.h H5Rpublic.h \
     H5RApublic.h H5Spublic.h H5Tpublic.h H5Zpublic.h H5pubconf.h hdf5.h \
-    H5api_adpt.h
+    H5api_adpt.h H5FDdpss.h
 
 ## Other header files (not to be installed)...
 PRIVATE_HDR=H5private.h H5Aprivate.h H5Apkg.h H5ACprivate.h H5Bprivate.h \