HDF5 version 1.8.1 released on Thu May 29 15:28:55 CDT 2008
================================================================================

INTRODUCTION
============

This document describes the differences between the HDF5-1.8.1 release 
and HDF5 1.8.0, and contains information on the platforms tested and known 
problems in HDF5-1.8.1.  For more details, see the files
HISTORY-1_0-1_8_0_rc3.txt and HISTORY-1_8.txt in the release_docs/ directory 
of the HDF5 source.

Links to the HDF5 1.8.1 source code, documentation, and additional materials
can be found on the HDF5 web page at:

     http://www.hdfgroup.org/products/hdf5/

The HDF5 1.8.1 release can be obtained from:

     http://www.hdfgroup.org/HDF5/release/obtain5.html

User documentation for 1.8.1 can be accessed directly at this location: 

     http://www.hdfgroup.org/HDF5/doc/

New features in the HDF5-1.8.x release series, including brief general 
descriptions of some new and modified APIs, are described in the "What's New 
in 1.8.0?" document:

     http://www.hdfgroup.org/HDF5/doc/ADGuide/WhatsNew180.html

All new and modified APIs are listed in detail in the "HDF5 Software Changes 
from Release to Release" document, in the section "Release 1.8.1 (current 
release) versus Release 1.8.0":

     http://www.hdfgroup.org/HDF5/doc/ADGuide/Changes.html

If you have any questions or comments, please send them to the HDF Help Desk:

     help@hdfgroup.org


CONTENTS
========

- New Features
- Support for new platforms and languages
- Bug Fixes since HDF5-1.8.0
- Platforms Tested
- Supported Configuration Features Summary
- Known Problems


New Features
============

        Configuration
        -------------
        - The lib/libhdf5.settings file contains much more configure
          information. (AKC - 2008/05/18)

        - The new configure option "--disable-sharedlib-rpath" disables 
          embedding the '-Wl,-rpath' information into executables when 
          shared libraries are produced, and instead solely relies on the 
          information in LD_LIBRARY_PATH. (MAM - 2008/05/15)

        - Configuration suite now uses Autoconf 2.61, Automake 1.10.1, and 
          Libtool 2.2.2 (MAM - 2008/05/01)

        Source code distribution
        ========================

        Library
        -------
        - None

        Parallel Library
        ----------------
        - None

        Tools
        -----
        - h5repack: Reinstated the -i and -o command line flags to specify 
          input and output files.  h5repack now understands both the old
          syntax (with -i and -o) and the new syntax introduced in Release
          1.8.0.  (PVN - 2008/05/23)
        - h5dump: Added support for external links, displaying the object that 
          an external link points to. (PVN - 2008/05/12)
        - h5dump: Added an option, -m, to allow user-defined formatting in the 
          output of floating point numbers. (PVN - 2008/05/06)
        - h5dump, in output of the -p option: Added effective data compression 
          ratio to the dataset storage layout output when a compression filter 
          has been applied to a dataset.  (PVN - 2008/05/01)

        F90 API
        ------
        New H5A, H5G, H5L, H5O, and H5P APIs to enable 1.8 features were
        added. See "Release 1.8.1 (current release) versus Release 1.8.0" in 
        the document "HDF5 Software Changes from Release to Release"
        (http://hdfgroup.org/HDF5/doc/ADGuide/Changes.html) for the 
        complete list of the new APIs.

        C++ API
        ------
        - None


Support for New Platforms, Languages, and Compilers
===================================================
        - Both serial and parallel HDF5 are supported for the Red Storm machine 
          which is a Cray XT3 system.

        - The Fortran library will work correctly if compiled with the -i8 
          flag.  This has been tested with the g95, PGI and Intel Fortran 
          compilers.


Bug Fixes since HDF5-1.8.0 
==========================

        Configuration
        -------------
        - None

        Source code distribution
        ========================

        Library
        -------
        - Chunking:  Chunks greater than 4GB are disallowed. 
          (QAK - 2008/05/16)
        - Fixed the problem with searching for a target file when following 
          an external link.  The search pattern will depend on whether the 
          target file's pathname is an absolute or a relative path. 
          Please see the H5Lcreate_external description in the "HDF5 
          Reference Manual" (http://hdfgroup.org/HDF5/doc/RM/RM_H5L.html).
          (VC - 2008/04/08)
        - Fixed possible file corruption bug when encoding datatype
          descriptions for compound datatypes whose size was between
          256 and 511 bytes and the file was opened with the "use the
          latest format" property enabled (with H5Pset_libver_bounds).
          (QAK - 2008/03/13)
        - Fixed bug in H5Aget_num_attrs() routine to correctly handle an 
          invalid location identifier.  (QAK - 2008/03/11)

        Parallel Library
        ----------------
        - None

        Tools
        -----
        - Fixed bug in h5diff that prevented datasets and attributes with
          variable-length string elements from comparing correctly.
          (QAK - 2008/02/28)
        - Fixed bug in h5dump that caused binary output to be made only for 
          the first dataset, when several datasets were requested.
          (PVN - 2008/04/07)

        F90 API
        ------
        - The h5tset(get)_fields subroutines were missing the parameter to 
          specify a sign position; fixed.  (EIP - 2008/05/23)
        - Many APIs were fixed to work with the 8-byte integers in Fortran vs.
          4-byte integers in C. This change is trasparent to user applications.

        C++ API
        ------
        - The class hierarchy was revised to address the problem reported
          in bugzilla #1068, Attribute should not be derived from base
          class H5Object.  Classes AbstractDS was moved out of H5Object.
          Class Attribute now multiply inherits from IdComponent and
          AbstractDs and class DataSet from H5Object and AbstractDs.
          In addition, data member IdComponent::id was moved into subclasses:
          Attribute, DataSet, DataSpace, DataType, H5File, Group, and PropList.
          (BMR - 2008/05/20)
	- IdComponent::dereference was incorrect; it was changed from:
		void IdComponent::dereference(IdComponent& obj, void* ref)
	  to:
		void H5Object::dereference(H5File& h5file, void* ref)
		void H5Object::dereference(H5Object& obj, void* ref)
	  (BMR - 2008/05/20)
        - Revised Attribute::write and Attribute::read wrappers to handle
          memory allocation/deallocation properly. (bugzilla 1045)
          (BMR - 2008/05/20)


Platforms Tested
================
The following platforms and compilers have been tested for this release.

    Cray XT3 (2.0.41)             cc (pgcc) 7.1-4
    (red storm)                   ftn (pgf90) 7.1-4
				  CC (pgCC) 7.1-4
                                  mpicc 1.0.2
                                  mpif90 1.0.2

    FreeBSD 6.2-STABLE i386       gcc 3.4.6 [FreeBSD] 20060305
    (duty)                        g++ 3.4.6 [FreeBSD] 20060305
                                  gcc 4.2.1 20080123
                                  g++ 4.2.1 20080123
                                  gfortran 4.2.1 20070620

    FreeBSD 6.2-STABLE amd64      gcc 3.4.6 [FreeBSD] 20060305
    (liberty)                     g++ 3.4.6 [FreeBSD] 20060305
                                  gcc 4.2.1 20080123
                                  g++ 4.2.1 20080123
                                  gfortran 4.2.1 20080123

    IRIX64 6.5 (64 & n32)         MIPSpro cc 7.4.4m
                                  F90 MIPSpro 7.4.4m 
                                  C++ MIPSpro cc 7.4.4m

    Linux 2.6.9 (RHEL4)           Intel 10.0 compilers
    (abe.ncsa.uiuc.edu)

    Linux 2.4.21-47               gcc 3.2.3 20030502
    (osage)

    Linux 2.6.9-42.0.10           gcc,g++ 3.4.6 20060404, G95 (GCC 4.0.3) 
    (kagiso)                      PGI 7.1-6 (pgcc, pgf90, pgCC)
                                  Intel 9.1 (icc, ifort, icpc)

    Linux 2.6.16.27 x86_64 AMD    gcc 4.1.0 (SuSE Linux), g++ 4.1.0, 
    (smirom)                          g95 (GCC 4.0.3)
                                  PGI 7.1-6 (pgcc, pgf90, pgCC)
                                  Intel 9.1 (icc, ifort, icpc)

    Linux 2.6.5-7.252.1-rtgfx #1  Intel(R) C++ Version 9.0
          SMP ia64                Intel(R) Fortran Itanium(R) Version 9.0 
    (cobalt)                      SGI MPI

    SunOS 5.8 32,46               Sun WorkShop 6 update 2 C 5.3
     (Solaris 2.8)                Sun WorkShop 6 update 2 Fortran 95 6.2
                                  Sun WorkShop 6 update 2 C++ 5.3

    SunOS 5.10                    cc: Sun C 5.8 
    (linew)                       f90: Sun Fortran 95 8.2 
                                  CC: Sun C++ 5.8 

    Xeon Linux 2.4.21-32.0.1.ELsmp-perfctr-lustre
    (tungsten)                    gcc 3.2.2 20030222
                                  Intel(R) C++ Version 9.0
                                  Intel(R) Fortran Compiler Version 9.0

    IA-64 Linux 2.4.21.SuSE_309.tg1 ia64
    (NCSA tg-login)               gcc 3.2.2
                                  Intel(R) C++ Version 8.1
                                  Intel(R) Fortran Compiler Version 8.1
                                  mpich-gm-1.2.6..14b-intel-r2

    Intel 64 Linux 2.6.9-42.0.10.EL_lustre-1.4.10.1smp
    (abe)                         gcc 3.4.6 20060404
                                  Intel(R) C++ Version 10.0
                                  Intel (R) Fortran Compiler Version 10.0
                                  mvapich2-0.9.8p2patched-intel-ofed-1.2

    Windows XP                    Visual Studio .NET
                                  Visual Studio 2005 w/ Intel Fortran 9.1
                                  Cygwin(native gcc compiler and g95)
                                  MinGW(native gcc compiler and g95)

    Windows XP x64                Visual Studio 2005 w/ Intel Fortran 9.1

    Windows Vista                 Visual Studio 2005

    MAC OS  10.5.2 (Intel)        i686-apple-darwin9-gcc-4.0.1 (GCC) 4.0.1
                                  GNU Fortran (GCC) 4.3.0 20070810
                                  G95 (GCC 4.0.3 (g95 0.91!) Apr 24 2008)


Supported Configuration Features Summary
========================================

    In the tables below
          y   = tested and supported
          n   = not supported or not tested in this release
          x   = not working in this release
          dna = does not apply
          ( ) = footnote appears below second table
          <blank> = testing incomplete on this feature or platform 

Platform                 C        F90    F90      C++   zlib  SZIP
                         parallel        parallel
SunOS5.10 64-bit         n        y      n        y     y     y
SunOS5.10 32-bit         n        y      n        y     y     y
IRIX64_6.5 64-bit        n        y      y        y     y     y
IRIX64_6.5 32-bit        n        n      n        n     y     y
Windows XP               n        y(15)  n(15)    y     y     y
Windows XP x64           n        y(15)  n(15)    y     y     y
Windows Vista            n        n      n        y     y     y
Mac OS X 10.5 Intel      n        y      n        y     y     y
FreeBSD 4.11             n        n      n        y     y     y
RedHat EL3  W       (3)  y(1)     y(10)  y(1)     y     y     y
RedHat EL3  W Intel (3)  n        y      n        y     y     n
RedHat EL3  W PGI   (3)  n        y      n        y     y     n
SuSe x86_64 gcc  (3,12)  y(2)     y(11)  y(2)     y     y     y
SuSe x86_64 Int  (3,12)  n        y(13)  n        y     y     n
SuSe x86_64 PGI  (3,12)  n        y(8)   n        y     y     y
Linux 2.4 Xeon C 
    Lustre Intel  (3,6)  n        y      n        y     y     n
Linux 2.6 SuSE ia64 C 
    Intel         (3,7)  y        y      y        y     y     n
Linux 2.6 SGI Altix 
    ia64 Intel      (3)  y        y      y        y     y     y
Linux 2.6 RHEL C
    Lustre Intel    (5)  y(4)     y      y(4)     y     y     n
Cray XT3 2.0.41          y        y      y        y     y     n


Platform                 Shared  Shared    Shared    Thread-  
                         C libs  F90 libs  C++ libs  safe     
Solaris2.10 64-bit       y       y         y         y        
Solaris2.10 32-bit       y       y         y         y        
IRIX64_6.5 64-bit        y       y         n         y        
IRIX64_6.5 32-bit        y       dna       y         y        
Windows XP               y       y(15)     y         y        
Windows XP x64           y       y(15)     y         y        
Windows Vista            y       n         n         y        
Mac OS X 10.3            y                           n        
FreeBSD 4.11             y       n         y         y        
RedHat EL3  W       (3)  y       y(10)     y         y        
RedHat EL3  W Intel (3)  y       y         y         n        
RedHat EL3  W PGI   (3)  y       y         y         n        
SuSe x86_64 W GNU (3,12) y       y         y         y        
SuSe x86_64 W Int (3,12) y       y         y         n        
SuSe x86_64 W PGI (3,12) y       y         y         n        
Linux 2.4 Xeon C 
    Lustre Intel    (6)  y       y         y         n        
Linux 2.4 SuSE 
    ia64 C Intel    (7)  y       y         y         n        
Linux 2.4 SGI Altix 
    ia64 Intel           y                           n        
Linux 2.6 RHEL C
    Lustre Intel    (5)  y        y        y         n
Cray XT3 2.0.41          n       n         n         n        n

    Notes: (1)  Using mpich2 1.0.6.
           (2)  Using mpich2 1.0.7.
           (3)  Linux 2.6 with GNU, Intel, and PGI compilers, as indicated.  
                  W or C indicates workstation or cluster, respectively.
           (4)  Using mvapich2 0.9.8.
           (5)  Linux 2.6.9-42.0.10.  Xeon cluster with ELsmp_perfctr_lustre 
                  and Intel compilers
           (6)  Linux 2.4.21-32.0.1.  Xeon cluster with ELsmp_perfctr_lustre 
                  and Intel compilers
           (7)  Linux 2.4.21, SuSE_292.till.  Ia64 cluster with Intel compilers
           (8)  pgf90
           (9)  With Compaq Visual Fortran 6.6c compiler.
           (10) With PGI and Absoft compilers.
           (11) PGI and Intel compilers for both C and Fortran
           (12) AMD Opteron x86_64
           (13) ifort
           (14) Yes with C and Fortran, but not with C++
           (15) Using Visual Studio 2005 or Cygwin
           (16) Not tested for this release.
    Compiler versions for each platform are listed in the preceding
    "Platforms Tested" table.


Known Problems
==============
* For Red Storm, a Cray XT3 system, the yod command sometimes gives the
  message,  "yod allocation delayed for node recovery".  This interferes with
  test suites that do not expect seeing this message.  See the section of "Red
  Storm" in file INSTALL_parallel for a way to deal with this problem.
  AKC - 2008/05/28

* For Red Storm, a Cray XT3 system, the tools/h5ls/testh5ls.sh will fail on
  the test "Testing h5ls -w80 -r -g tgroup.h5" fails.  This test is
  expected to fail and exit with a non-zero code but the yod command does
  not propagate the exit code of the executables. Yod always returns 0 if it
  can launch the executable.  The test suite shell expects a non-zero for
  this particular test, therefore it concludes the test has failed when it
  receives 0 from yod.  To bypass this problem for now, change the following
  lines in the tools/h5ls/testh5ls.sh.
  ======== Original =========
  # The following combination of arguments is expected to return an error message
  # and return value 1
  TOOLTEST tgroup-1.ls 1 -w80 -r -g tgroup.h5
  ======== Skip the test =========
  echo SKIP TOOLTEST tgroup-1.ls 1 -w80 -r -g tgroup.h5
  ======== end of bypass ========
  AKC - 2008/05/28

* We have discovered two problems when running collective IO parallel HDF5 
  tests with chunking storage on the ChaMPIon MPI compiler on tungsten, a 
  Linux cluster at NCSA.

  Under some complex selection cases: 
  1) MPI_Get_element returns the wrong value.
  2) MPI_Type_struct also generates the wrong derived datatype and corrupt 
     data may be generated.
  These issues arise only when turning on collective IO with chunking storage 
  with some complex selections. We have not found these problems on other 
  MPI-IO compilers. If you encounter these problems, you may use independent 
  IO instead.

  To avoid this behavior, change the following line in your code
      H5Pset_dxpl_mpio(xfer_plist, H5FD_MPIO_COLLECTIVE);
  to
      H5Pset_dxpl_mpio(xfer_plist, H5FD_MPIO_INDEPENDENT);

  KY - 2007/08/24

* For SNL, spirit/liberty/thunderbird: The serial tests pass but parallel
  tests failed with MPI-IO file locking message. AKC - 2007/6/25

* On Intel 64 Linux cluster (RH 4, Linux 2.6.9) with Intel 10.0 compilers, 
  use -mp -O1 compilation flags to build the libraries. A higher level of 
  optimization causes failures in several HDF5 library tests. 

* For LLNL, uP: both serial and parallel tests pass.  
  Zeus: Serial tests pass but parallel tests fail with a known problem in MPI.
  ubgl: Serial tests pass but parallel tests fail. 

* Configuring with --enable-debug=all produces compiler errors on most
  platforms:  Users who want to run HDF5 in debug mode should use
  --enable-debug rather than --enable-debug=all to enable debugging
  information on most modules.

* On Mac OS 10.4, test/dt_arith.c has some errors in conversion from long
  double to (unsigned) long long and from (unsigned) long long to long double. 

* On Altix SGI with Intel 9.0, testmeta.c would not compile with -O3
  optimization flag.

* On VAX, the Scaleoffset filter is not supported.  The Scaleoffset filter 
  supports only the IEEE standard for floating-point data; it cannot be applied 
  to HDF5 data generated on VAX. 

* On Cray X1, a lone colon on the command line of h5dump --xml (as in
  the testh5dumpxml.sh script) is misinterpereted by the operating system
  and causes an error.

* On mpich 1.2.5 and 1.2.6, if more than two processes contribute no IO and 
  the application asks to do collective IO, we have found that when using 4 
  processors, a simple collective write will sometimes be hung. This can be 
  verified with t_mpi test under testpar.

* On IRIX6.5, when the C compiler version is greater than 7.4, complicated
  MPI derived datatype code will work. However, the user should increase
  the value of the MPI_TYPE_MAX environment variable to some appropriate value 
  to use collective irregular selection code.  For example, the current 
  parallel HDF5 test needs to raise MPI_TYPE_MAX to 200,000 to pass the test. 

* A dataset created or rewritten with a v1.6.3 library or after cannot be read 
  with the v1.6.2 library or before when the Fletcher32 EDC filter is enabled.
  There was a bug in the calculation of the Fletcher32 checksum in the 
  library before v1.6.3; the checksum value was not consistent between big-
  endian and little-endian systems.  This bug was fixed in Release 1.6.3.  
  However, after fixing the bug, the checksum value was no longer the same as 
  before on little-endian system.  Library releases after 1.6.4 can still read 
  datasets created or rewritten with an HDF5 library of v1.6.2 or before.  
  SLU - 2005/6/30

* For version 6 (6.02 and 6.04) of the Portland Group compiler on the AMD 
  Opteron processor, there is a bug in the compiler for optimization(-O2).  
  The library failed in several tests, all related to the MULTI driver.  
  The problem has been reported to the vendor.  

* On IBM AIX systems, parallel HDF5 mode will fail some tests with error
  messages like "INFO: 0031-XXX ...".  This is from the command `poe'.
  Set the environment variable MP_INFOLEVEL to 0 to minimize the messages
  and run the tests again.

  The tests may fail with messages like "The socket name is already in use",  
  but HDF5 does not use sockets.  This failure is due to problems with the 
  poe command trying to set up the debug socket.  To resolve this problem, 
  check to see whether there are many old /tmp/s.pedb.* files staying around.  
  These are sockets used by the poe command and left behind due to failed 
  commands.  First, ask your system administrator to clean them out.  
  Lastly, request IBM to provide a means to run poe without the debug socket.

* The --enable-static-exec configure flag fails to compile for Solaris
  platforms. This is due to the fact that not all of the system libraries on 
  Solaris are available in a static format.

  The --enable-static-exec configure flag also fails to correctly compile
  on IBM SP2 platforms for serial mode. The parallel mode works fine with 
  this option.
  
  It is suggested that you do not use this option on these platforms
  during configuration.

* With the gcc 2.95.2 compiler, HDF5 uses the `-ansi' flag during
  compilation. The ANSI version of the compiler complains about not being
  able to handle the `long long' datatype with the warning:

        warning: ANSI C does not support `long long'
  
  This warning is innocuous and can be safely ignored.

* The ./dsets tests fail on the TFLOPS machine if the test program,
  dsets.c, is compiled with the -O option.  The HDF5 library still works
  correctly with the -O option.  The test program works fine if it is
  compiled with -O1 or -O0.  Only -O (same as -O2) causes the test
  program to fail.

* Not all platforms behave correctly with Szip's shared libraries. Szip is
  disabled in these cases, and a message is relayed at configure time. Static
  libraries should be working on all systems that support Szip and should be
  used when shared libraries are unavailable. 

  There is also a configure error on Altix machines that incorrectly reports 
  when a version of Szip without an encoder is being used.

* On some platforms that use Intel and Absoft compilers to build the HDF5 
  Fortran library, compilation may fail for fortranlib_test.f90, fflush1.f90 
  and fflush2.f90 complaining about the exit subroutine. Comment out the line 
  IF (total_error .ne. 0) CALL exit (total_error).

* Information about building with PGI and Intel compilers is available in
  the INSTALL file sections 4.7 and 4.8.

* On at least one system, SDSC DataStar, the scheduler (in this case
  LoadLeveler) sends job status updates to standard error when you run 
  any executable that was compiled with the parallel compilers.

  This causes problems when running "make check" on parallel builds, as 
  many of the tool tests function by saving the output from test runs,
  and comparing it to an exemplar.  

  The best solution is to reconfigure the target system so it no longer
  inserts the extra text.  However, this may not be practical.

  In such cases, one solution is to "setenv HDF5_Make_Ignore yes" prior to 
  the configure and build.  This will cause "make check" to continue after 
  detecting errors in the tool tests.  However, in the case of SDSC DataStar,
  it also leaves you with some 150 "failed" tests to examine by hand.

  A second solution is to write a script to run serial tests and filter
  out the text added by the scheduler.  A sample script used on SDSC
  DataStar is given below, but you will probably have to customize it 
  for your installation.  

  Observe that the basic idea is to insert the script as the first item 
  on the command line which executes the the test.  The script then 
  executes the test and filters out the offending text before passing
  it on.

        #!/bin/csh

        set STDOUT_FILE=~/bin/serial_filter.stdout
        set STDERR_FILE=~/bin/serial_filter.stderr

        rm -f $STDOUT_FILE $STDERR_FILE

        ($* > $STDOUT_FILE) >& $STDERR_FILE

        set RETURN_VALUE=$status

        cat $STDOUT_FILE

        tail +3 $STDERR_FILE

        exit $RETURN_VALUE

  You get the HDF5 make files and test scipts to execute your filter script
  by setting the environment variable "RUNSERIAL" to the full path of the 
  script prior to running configure for parallel builds.  Remember to 
  "unsetenv RUNSERIAL" before running configure for a serial build.

  Note that the RUNSERIAL environment variable exists so that we can 
  prefix serial runs as necessary on the target system.  On DataStar,
  no prefix is necessary.  However on an MPICH system, the prefix might
  have to be set to something like "/usr/local/mpi/bin/mpirun -np 1" to
  get the serial tests to run at all.

  In such cases, you will have to include the regular prefix in your
  filter script.

* H5Ocopy() does not copy reg_ref attributes correctly when shared-message
  is turn on. The value of the reference in the destination attriubte is
  wrong. This H5Ocopy problem will affect the h5copy tool.

* In the C++ API, it appears that there are bugs in Attribute::write/read
  and DataSet::write/read for fixed- and variable-len strings.  The problems
  are being worked on and a patch will be provided when the fixes are
  available.

