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                           Newsletter #63
                           October 4, 2001


CONTENTS
                                            *******************************
. Data Corruption Problem in HDF5-1.4.2     * Visit the HDF home page     *
                                            * for up-to-date information  *
                                            *                             *
                                            *  http://hdf.ncsa.uiuc.edu/  *
                                            *                             *
                                            *******************************


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Data Corruption Problem in HDF5-1.4.2
=====================================

A data corruption problem has been found when reading or writing chunked
data in a manner that requires a datatype conversion.  A datatype 
conversion means that the read or write call uses a datatype that
is different than the datatype of the dataset.  For example, if a 
chunked dataset is of type H5T_IEEE_F32LE, and is written to using
H5Dwrite with a datatype of H5T_NATIVE_DOUBLE, the resulting dataset
may include corrupted data values.  There is NO indication that there
is a problem when this occurs.

If there is any possibility that you are using HDF5 in this manner, please
check your datasets and download the patched version of HDF5-1.4.2 as soon
as possible.  In any case, we recommend that you download the patch
at your earliest convenience.

The entire source code for 5-1.4.2-patch1 is available from:
   ftp://ftp.ncsa.uiuc.edu/HDF/HDF5/current/src/

You can obtain just the source files that changed from:
   ftp://ftp.ncsa.uiuc.edu/HDF/HDF5/current/src/patched-files/

Pre-compiled binaries which contain this fix are not yet available for all
of the platforms we support.  These will be added to the ftp server in
the next few days, as they are made available.

We apologize for the inconvenience this may cause.  Thank you for
supporting HDF5!


--------------------------------------------------------------
For questions regarding these or other HDF issues, contact:

   hdfhelp@ncsa.uiuc.edu