HDF Newsletter #147

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                             Newsletter #147
                            December 30, 2015


   - Release of HDF5-1.10.0-alpha0

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Release of HDF5-1.10.0-alpha0

We are very pleased to announce the release of HDF5-1.10.0-alpha0. It can
be obtained from The HDF Group Downloads page:


It can also be obtained directly from:


Documentation can be found in:


HDF5-1.10 is a major release containing many new features. The alpha0
release contains some but not all of the features that will be in HDF5-1.10.
More features will be added in upcoming alpha releases.

PLEASE BE AWARE that the file format is not yet stable. DO NOT keep files
until further notice.

Following are the new features in the HDF5-1.10.0-alpha0 release:

  o Concurrent Access to an HDF5 File: Single Writer / Multiple Reader (SWMR)

    The Single Writer / Multiple Reader or SWMR feature enables users to read
    data while concurrently writing it. Communications between the processes
    and file locking are not required. An HDF5 file under SWMR access must
    reside on a file system that complies with POSIX write() semantics.

  o Virtual Dataset (VDS)

    The VDS feature enables access to data stored in datasets in different
    HDF5 files using the standard H5D interface without rewriting or
    rearranging the data. Please note that the VDS feature can be used with

  o Scalable Chunk Indexing

    The indexing structure for chunked datasets has been changed to
    significantly improve performance.

  o Persistent Free File Space Tracking

    Usage patterns when working with an HDF5 file sometimes result in wasted
    space within the file. This can also impair access times when working with
    the resulting files. The new file space management feature provides
    strategies for managing space in a file to improve performance in both of
    these arenas.

We would greatly appreciate any feedback you might have regarding this release.
Please send your comments to The HDF Helpdesk (help@hdfgroup.org). If sending a
bug report, please include a C example program that we can use to reproduce the

Happy New Year!

For questions regarding these or other HDF issues, contact: