ABOUT HDF 4.1 Release 4
                                October 2000 

INTRODUCTION

This document describes the differences between HDF 4.1r3 and
HDF 4.1r4.  It is written for people who are familiar with
previous releases of HDF and wish to migrate to HDF 4.1r4.

The HDF 4.1r4 documentation can be found on the NCSA ftp server 
(ftp.ncsa.uiuc.edu) in the directory:

     /HDF/HDF/Documentation/HDF4.1r4/

First-time HDF users are encouraged to read the FAQ in this
release for more information about HDF.  Users can also look
at the home page for HDF at:

     http://hdf.ncsa.uiuc.edu/

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

     hdfhelp@ncsa.uiuc.edu

CONTENTS

- New Features and Changes
- Platforms Tested
- Known Problems

New Features and Changes:
========================

This release focuses on new features and changes added to the
GR interface.

o Two new utilities have been added to HDF, gif2hdf and hdf2gif.
  The gif2hdf utility will convert a GIF image into an HDF file
  containing a GR image. The hdf2gif utility will convert an HDF GR 
  image into a GIF image. 
  
o Chunking and chunking with compression have been added to the
  GR interface.

o JPEG compression with the GR interface was not working properly.
  This problem has been fixed.

Several hdp options have been added:
  
o Added -s option to dumpgr and dumpsds to allow printing data 
  as a stream instead of breaking the lines at 65 characters. 

o Added option -c to dumpgr and dumpsds to allow printing clean output 
  for attributes with type DFNT_CHAR. With this option, hdp will print 
  space characters, such as horizontal tabs, CRs, and LFs, as they are 
  instead of "\digit" (still the default.)  This option also prints "..." 
  for one or more null characters among the data.

o Added option -l to dumpgr to allow printing data in different interlace
  modes.


Platforms Tested:
================

HDF 4.1 Release 4 has been tested on the following platforms:

   Cray J90  (available after initial 4.1r4 release)
   Cray T3E                      
   DEC Alpha/Digital Unix
   DEC Alpha/OpenVMS
   Exemplar
   FreeBSD
   HP-UX 
   IRIX 
   IRIX64 (-n32, -64)
   Linux
   Solaris
   Solaris x86
   SP
   Windows NT/98/2000

For more information on the platforms that were tested and for
which we provide pre-compiled binaries, please refer to the following
web page (accessible from the HDF home page):

     http://hdf.ncsa.uiuc.edu/platforms.html


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

o The ncgen utility fails on the IBM SP.