HDF Newsletter #118

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                             Newsletter #118
                             February 18,2011

. 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:


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


The HDF5 1.8.6 documentation is located in:


For information on HDF5, see the HDF5 home page:


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

  - 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:


For questions regarding these or other HDF issues, contact: