path: root/release_docs/RELEASE.txt

HDF5 version 1.5.20 currently under development
================================================================================


INTRODUCTION

This document describes the differences between HDF5-1.4.0 and
HDF5-1.5-snap0, and contains information on the platforms tested and
known problems in HDF5-1.5-snap0. For more details check the HISTORY.txt
file in the HDF5 source.

The HDF5 documentation can be found on the NCSA ftp server
(ftp.ncsa.uiuc.edu) in the directory:

     /HDF/HDF5/docs/

For more information look at the HDF5 home page at:
   
    http://hdf.ncsa.uiuc.edu/HDF5/

If you have any questions or comments, please send them to:

    hdfhelp@ncsa.uiuc.edu

CONTENTS

- New Features
- Bug Fixes since HDF5-1.4.0
- Platforms Tested
- Known Problems

Bug Fixes since HDF5-1.4.2
==========================

Library
-------

    * Fixed bug with contiguous hyperslabs not being detected, causing
      slower I/O than necessary.
    * Fixed bug where non-aligned hyperslab I/O on chunked datasets was
      causing errors during I/O
    * The RCSID string in H5public.h was causing the C++ compiling problem
      because when it was included multiple times, C++ did not like multiple
      definitions of the same static variable.  All occurance of RCSID
      definition are removed since we have not used it consistently before.
    * Fixed bug with non-zero userblock sizes causing raw data to not write
      correctly. 
    * Fixed build on Linux systems with --enable-static-exec flag. It now
      works correctly.
    * IMPORTANT: Fixed file metadata corruption bug which could cause metadata
      data loss in certain situations.
    * The allocation by alignment (H5Pset_alignment) feature code somehow
      got dropped in some 1.3.x version. Re-implemented it with "new and
      improved" algorithm.  It keeps track of "wasted" file-fragment in
      the free-list too.
    * Removed limitation that the data transfer buffer size needed to be
      set for datasets whose dimensions were too large for the 'all' selection
      code to handle.  Any size dimensioned datasets should be handled
      correctly now.
    * Changed behavior of H5Tget_member_type to correctly emulate HDF5 v1.2.x
      when --enable-hdf5v1_2 configure flag is enabled.
    * Tweaked a few API functions to use 'size_t' instead of 'unsigned' or
      'hsize_t', which may cause errors in some cases.
    * Fixed a bug of H5pubconf.h causing repeated definitions if it is included
      more than once.  hdf5.h now includes H5public.h which includes
      H5pubconf.h.  Applications should #include hdf5.h which handles multiple
      inclusion correctly.
    * Fixed H5FDmpio.h to be C++ friendly by making Parallel HDF5 API's to be
      external to C++.
    * Fixed a bug in H5FD_mpio_flush() that might result in negative file seek
      if both MPIO and Split-file drivers are used together.
    * Added new parallel hdf5 tests in t_mpi.  The new test checks if the
      filesystem or the MPI-IO can really handle greater than 2GB files.
      If it fails, it prints information message only without failing the
      test.
    * Fixed a bug when reading chunked datasets where the edge of the dataset
      would be incorrectly detected and generate an assertion failure.
    * Fixed a bug where reading an entire dataset wasn't being handled
      optimally when the dataset had unlimited dimensions.  Dataset is read
      in a single low-level I/O now, instead of being broken into separate
      pieces internally.
    * Fixed a bug where reading or writing chunked data which needed datatype
      conversion could result in data values getting corrupted.
    * Fixed a bug where appending a point selection to the current selection
      would not actually append the point when there were no points defined
      currently.
    * Fixed a bug where 'or'ing a hyperslab with a 'none' selection would
      fail.  Now adds that hyperslab as the first hyperlab in the selection.
    * Fixed a bug in the 'big' test where quota limits weren't being detected
      properly if they caused close() to fail.
    * Fixed a bug in internal B-tree code where a B-tree was not being copied
      correctly.
    * Fixed an off-by-one error in H5Sselect_valid when hyperslab selections
      which would allow hyperslab selections which overlapped the edge of the
      selection by one element as valid.
    * Fixed the internal macros used to encode & decode file metadata, to avoid
      an unaligned access warning on IA64 machines.
    * Corrected behavior of H5Tinsert to not allow compound datatype fields to
      be inserted past the end of the datatype.
    * Retired the DPSS virtual file driver (--with-gridstorage configure
      option).
    * Fixed bug where variable-length datatypes for attributes was not working
      correctly.
    * Fixed bug where raw data re-allocated from the free-list would sometimes
      overlap with the metadata accumulator and get corrupted. QAK - 1/23/02

Configuration
-------------

    * Changed the default value of $NPROCS from 2 to 3 since 3 processes
      have a much bigger chance catching parallel errors than just 2.
    * Basic port to Compaq (nee DEC) Alpha OSF 5.
    * Added --enable-linux-lfs flag to allow more control over whether to enable
      or disable large file support on Linux.
    * Require HDF (a.k.a. hdf4) software that consists of a newer version
      of zlib library which consists of the compress2() function. Versions
      HDF version 4.1r3 and newer meets this requirement.  The compress2
      uses a newer compression algorithm used by the HDF5 library.  Also,
      4.1r3 has an hdp tool that can handle "loops" in Vgroups.
    * Can use just enable-threadsafe if the C compiler has builtin pthreads
      support.


Tools
-----

    * Fixed segfault when "-v" flag was used with the h5dumper.
    * Fixed so that the "-i" flag works correctly with the h5dumper.


Documentation
-------------


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

    * A helper script called ``h5cc'', which helps compilation of HDF5
      programs, is now distributed with HDF5. See the reference manual
      for information on how to use this feature.
    * C++ API:
        - Added two new member functions: Exception::getFuncName() and
          Exception::getCFuncName() to provide the name of the member
          function, where an exception is thrown.
        - IdComponent::operator= becomes a virtual function because
          DataType, DataSpace, and PropList provide their own
          implementation.  The new operator= functions invoke H5Tcopy,
          H5Scopy, and H5Pcopy to make a copy of a datatype, dataspace,
          and property list, respectively.
    * F90 API:
        - Added aditional parameter "dims" to the h5dread/h5dwrite and
          h5aread/h5awrite subroutines. This parameter is 1D array of size
          7 and contains the sizes of the data buffer dimensions. 
    * F90 static library is available on Windows platforms. See
      INSTALL_Windows.txt for details.
    * F90 APIs are available on HPUX 11.00 and IBM SP platforms.
    * File sizes greater than 2GB are now supported on Linux systems with
      version 2.4.x or higher kernels.
    * Added a global string variable H5_lib_vers_info_g which holds the
      HDF5 library version information.  This can be used to identify
      an hdf5 library or hdf5 application binary.
      Also added a verification of the consistency between H5_lib_vers_info_g
      and other version information in the source code.
    * H5 <-> GIF convertor has been added. This is available under 
      tools/gifconv. The convertor supports the ability to create animated
      gifs as well.
    * Parallel HDF5 now runs on the HP V2500 and HP N4000 machines.
    * Verified correct operation of library on Solaris 2.8 in both 64-bit and
      32-bit compilation modes.  See INSTALL document for instructions on
      compiling the distribution with 64-bit support.
    * Modified the Pablo build procedure to permit building of the instrumented
      library to link either with the Trace libraries as before or with the
      Pablo Performance Caputure Facility.
    * Improved regular hyperslab I/O by about a factor of 6 or so.
    * Added two simple parallel performance tests as mpi-perf.c (MPI
      performance) and perf.c (PHDF5 performance) in testpar.
    * Added a parallel HDF5 example examples/ph5example.c to illustrate
      the basic way of using parallel HDF5.
    * Added a new public macro, H5_VERS_INFO, which is a string holding
      the HDF5 library version information.  This string is also compiled
      into all HDF5 binary code which helps to identify the version
      information of the binary code.  One may use the Unix strings
      command on the binary file and looks for the pattern "HDF5 library
      version".
    * Added new checking in H5check_version() to verify the five HDF5 version
      information macros (H5_VERS_MAJOR, H5_VERS_MINOR, H5_VERS_RELEASE,
      H5_VERS_SUBRELEASE and H5_VERS_INFO) are consistent.
    * Added perform programs to test the HDF5 library performance.  Programs
      are installed in directory perform/.
    * The H5Pset_fapl_split() accepts raw and meta file names similar to the
      syntax of H5Pset_fapl_multi() in addition to what it used to accept.
    * Added a new test to verify the information provided by the configure
      command.
    * As part of the transition to using generic properties everywhere, the
      parameter of H5Pcreate changed from H5P_class_t to hid_t, as well
      the return type of H5Pget_class changed from H5P_class_t to hid_t.
      Further changes are still necessary and will be documented here as they
      are made.
    * Improved performance of single, contiguous hyperslabs when reading or
      writing.
    * Improved performance of non-contiguous hyperslabs (built up with
      several hyperslab selection calls).
    * Removed H5P(get|set)_hyper_cache API function, since the property is no
      longer used.
    * Added a new file access property, file close degree, to control file 
      close behavior.  It has four values, H5F_CLOSE_WEAK, H5F_CLOSE_SEMI,
      H5F_CLOSE_STRONG, and H5F_CLOSE_DEFAULT.  Two correspont functions 
      H5Pset_fclose_degree and H5Pget_fclose_degree are also provided.  Two 
      new functions H5Fget_obj_count and H5Fget_obj_ids are offerted to assist
      this new feature.  For full details, please refer to the reference 
      manual under the description of H5Fcreate, H5Fopen, H5Fclose and the 
      functions mentioned above. 
    * Changed internal error handling macros to reduce code size of library by
      about 10-20%.
    * Added H5Rget_obj_type() API function, which performs the same functionality
      as H5Rget_object_type(), but requires the reference type as a parameter
      in order to correctly handle dataset region references.  Moved
      H5Rget_object_type() to be only compiled into the library when v1.4
      compatibility is enabled.
    * Parallel HDF5 is now supported on HP-UX 11.00 platforms.
    * Added support to read/write portions of chunks directly, if they are
      uncompressed and too large to cache.  This should speed up I/O on chunked
      datasets for a few more cases.  -QAK, 1/31/02


Platforms Tested
================

  AIX 4.3.3.0 (IBM SP powerpc)  mpcc_r 3.6.6
  Cray T3E sn6711 2.0.5.45      Cray Standard C Version 6.4.0.0
                                Cray Fortran Version 3.4.0.2
  Cray SV1 sn9605 10.0.0.7      Cray Standard C Version 6.4.0.0
                                Cray Fortran Version 3.4.0.2
  FreeBSD 4.3                   gcc 2.95.2
                                g++ 2.95.2
  HP-UX B.10.20                 HP C  HP92453-01 A.10.32.30
  HP-UX B.11.00                 HP C  HP92453-01 A.11.00.13
                                HP C  HP92453-01 A.11.01.20
  IRIX 6.5                      MIPSpro cc 7.30
  IRIX64 6.5 (64 & n32)         MIPSpro cc 7.3.1m
                                mpt.1.4.0.2
                                mpich-1.2.1
  Linux 2.4.4                   gcc-2.95.3
                                g++ 2.95.3
  Linux 2.2.16-3smp             gcc-2.95.2
                                g++ 2.95.2
                                pgf90 3.1-3
  OSF1 V4.0                     DEC-V5.2-040
                                Digital Fortran 90 V4.1-270
  SunOS 5.6                     WorkShop Compilers 5.0 98/12/15 C 5.0 
  (Solaris 2.6)                 WorkShop Compilers 5.0 99/10/25 Fortran 90
                                       2.0 Patch 107356-04
                                Workshop Compilers 5.0 98/12/15 C++ 5.0
  SunOS 5.7                     WorkShop Compilers 5.0 98/12/15 C 5.0
  (Solaris 2.7)                 WorkShop Compilers 5.0 99/10/25 Fortran 90
                                       2.0 Patch 107356-04
                                Workshop Compilers 5.0 98/12/15 C++ 5.0
  TFLOPS r1.0.4 v4.0            mpich-1.2.1 with local changes
  Windows NT4.0, 2000 (NT5.0)   MSVC++ 6.0
  Windows 98                    MSVC++ 6.0

Known Problems
==============
* Datasets or attributes which have a variable-length string datatype are not
  printing correctly with h5dump and h5ls.

* DLLs do not work on Windows 98 

* RELEASE DLLs will fail on some tests on Windows 2000 with Microsoft visual 
  studio 6.0 due to memory allocation problems caused by compiler.  
  Users are encouraged to go to microsoft site  to find and install
  visual studio 6.0 service pack 5. After that, release dlls will work.

* The stream-vfd test uses ip port 10007 for testing. If another
  application is already using that port address, the test will hang
  indefinitely and has to be terminated by the kill command. To try the
  test again, change the port address in test/stream_test.c to one not
  being used in the host.

* 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 platform for the serial mode. The parallel mode works fine
  with this option.
  
  It is suggested that you don't use this option on these platforms
  during configuration.

* With the gcc 2.95.2 compiler, HDF 5 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.

* SunOS 5.6 with C WorkShop Compilers 4.2:  Hyperslab selections will 
  fail if library is compiled using optimization of any level.

* h5toh4 converter fails two cases (tstr.h5 and tmany.h5) for release dll
  version on windows 2000 and NT. The reason is possibly due to windows
  NT DLL convention on freeing memory. It seems that memory cannot be
  free across library or DLL. It is still under investigated.

* The Stream VFD was not tested yet under Windows. It is not supported
  in the TFLOPS machine.

* Shared library option is broken for IBM SP and some Origin 2000
  platforms. One needs to run ./configure with '--disable-shared'

* The ./dsets tests failed in 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.

* Certain platforms give false negatives when testing h5ls:

    - Solaris x86 2.5.1, Cray T3E and Cray J90 give errors during testing
      when displaying object references in certain files.  These are
      benign differences due to the difference in sizes of the objects
      created on those platforms. h5ls appears to be dumping object
      references correctly.

    - Cray J90 (and Cray T3E?) give errors during testing when displaying
      some floating-point values. These are benign differences due to
      the different precision in the values displayed and h5ls appears to
      be dumping floating-point numbers correctly.

* Before building HDF5 F90 Library from source on Crays (T3E and J90) 
  replace H5Aff.f90, H5Dff.f90 and H5Pff.f90 files in the fortran/src
  subdirectory in the top level directory with the Cray-specific files
  from the site:

  ftp://hdf.ncsa.uiuc.edu/pub/ougoing/hdf5/hdf5-1.4.0-beta/F90_source_for_Crays