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                            Newsletter #118
                            February 18,2011 

CONTENTS
. Release of HDF5-1.8.6

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Release of HDF5-1.8.6
=====================

The HDF5-1.8.6 release is now available. Many thanks to the users on the
HDF-Forum who helped us test this release.

HDF5-1.8.6 can be downloaded from:

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

This page can be accessed from The HDF Group Downloads page:

    http://www.hdfgroup.org/downloads/

The HDF5 1.8.6 documentation is located in:

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

For information on HDF5, see the HDF5 home page:

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

HDF5 1.8.6 is a minor release, but contains important new features and
bug fixes. New features and changes in this release include the following:

 - Many improvements have been made for CMake support.

 - Many memory issues were fixed. 

 - Several performance improvements have been added.

   Improvements were made to the library's internal mechanism for handling
   partial I/O. The library can now detect situations where a memory selection
   has the same shape and size as a selection in a dataset in the file. For
   example, when writing a 2D array into a slice of the same shape and size of
   a 3D array across the slowest changing dimension, performance has been
   shown to improve by as much as 80x in our nightly performance regression
   test framework. 

 - Support was added for thread safety on Windows using the Windows
   threads library. This feature is supported with Windows Vista and 
   CMake.

 - A bug was fixed that caused big endian machines to generate corrupt files
   when using the scale-offset filter with floating point data or fill values.
   Note that such datasets will NO LONGER BE READABLE by any machine after
   this release. If you have been archiving data that used this filter please
   contact us as soon as possible, so that we create a tool to correct
   the problem. 

 - In this release we have addressed the issue that affected applications
   built with HDF5 versions 1.6.3 and earlier.

   Applications (such as IDL 7.0) that were built with HDF5-1.6.3 or earlier,
   were not able to read files created by HDF5-1.8 in spite of the fact that
   the files did not contain any new features. For reading the files, the old
   libraries relied on the presence of cached symbol table information found
   in the groups' symbol table entries. With HDF5-1.8, this cached
   information was deemed redundant and was removed, causing the problem.
   HDF5-1.8.6 has been modified to address this issue. Specifically, the
   library now always writes cached symbol table information to a group's
   symbol table entry.

This release contains many other important changes not listed here.
Please be sure to read the Release Notes, for a comprehensive list of
new features and bug fixes:

    http://www.hdfgroup.org/ftp/HDF5/current/src/hdf5-1.8.6-RELEASE.txt


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For questions regarding these or other HDF issues, contact:

   help@hdfgroup.org