HDF5 Release 1.2.2-pre0
    			Under Development


INTRODUCTION

This document describes the differences between HDF5-1.2.1 and 
HDF5-1.2.2, and contains information on the platforms where HDF5-1.2.2
was tested(??????????) and known problems in HDF5-1.2.2. For more details check the
HISTORY 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

- Bug fixes since HDF5-1.2.1 
- Known Problems
- Platforms Tested


Features added since HDF5-1.2.1
===============================
   * Added internal free-lists to reduce memory required by the library and
     H5garbage_collect API function

Bug fixes since HDF5-1.2.1
==========================
   * h5dump correctly displays compound datatypes.
   * Corrected an error in h5toh4 which did not convert the 32bits
     int from HDF5 to HDF4 corectly for the T3E platform.
   * Corrected a floating point number conversion error for the
     Cray J90 platform.  The error did not convert the value 0.0
     correctly.
   * h5dump correctly displays the committed copy of predefined types
     correctly.
   * New features added to snapshots.  Use 'snapshot help' to see a
     complete list of features.
   * Fixed error in H5Giterate which was not updating the "index" parameter
     correctly.
   * Fixed error in hyperslab iteration which was not walking through the
     correct sequence of array elements if hyperslabs were staggered in a
     certain pattern
   * Fixed several other problems in hyperslab iteration code.
   * Fixed another H5Giterate bug which was causes groups with large numbers
     of objects in them to misbehave when the callback function returned
     non-zero values.
   * Changed return type of H5Aiterate and H5A_operator_t typedef to be
     herr_t, to align them with the dataset and group iterator functions.
   * Changed H5Screate_simple and H5Sset_extent_simple to not allow dimensions
     of size 0 with out the same dimension being unlimited.
   * QAK - 4/19/00 - Improved metadata hashing & caching algorithms to avoid
     many hash flushes and also remove some redundant I/O when moving metadata
     blocks in the file.
   * The libhdf5.settings file shows the correct machine byte-sex.
   * h5dump correctly displays opaque and bitfield types.

Known Problems:
==============

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

Platforms tested
=================

  AIX 4.3.2 (IBM SP)            3.6.6
  Cray T3E 2.0.4.81             cc 6.3.0.1
                                mpt.1.3
  FreeBSD 3.3-STABLE            gcc 2.95.2
  HP-UX B.10.20                 HP C  HP92453-01 A.10.32
  IRIX 6.5                      MIPSpro cc 7.30
  IRIX64 6.5 (64 & n32)         MIPSpro cc 7.3.1m
                                mpt.1.3 (SGI MPI 3.2.0.0)

  Linux 2.2.10 SuSE             egcs-2.91.66               configured with
  (i686-pc-linux-gnu)                                      --disable-hsizet
                                mpich-1.2.0 egcs-2.91.66 19990314/Linux 

  OSF1 V4.0                     DEC-V5.2-040
  SunOS 5.6                     cc WorkShop Compilers 4.2  no optimization
  SunOS 5.7                     cc WorkShop Compilers 5.0
  TFLOPS 2.8                    cicc (pgcc Rel 3.0-5i)
                                mpich-1.1.2 with local changes
  Windows NT4.0 sp5             MSVC++ 6.0