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/  CDF V3.4.1 Release Notes  /
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1. Compatibility with CDF 3.3.*, 3.2, 3.1 , 2.7.2 and Earlier Versions

CDF V3.4.1 is backward compatible with the previous versions of CDF, and it 
can read CDF files that were created with earlier versions.

If a file was created with CDF 2.7 and read and modified by CDF 3.*, the 
resultant file will be saved in the CDF 2.7 format, not CDF 3.*.  The same 
principle applies to files that were created with CDF 2.5 and 2.6.  CDF 
files that are created from scratch with CDF V3.4.* are compatible in file
structure with all CDF 3.*, but not compatible (due to a 64-bit file offsets
used since CDF 3.0 versions) with CDF 2.7.2 or earlier, and an attempt to
read CDF 3.* files from CDF 2.7.2 or earlier will produce an error. Since a
couple of new data types is added, applications based on V3.3.* and earilier
will not be able access the V3.4 files if the files have the data in those
new types. However, if the V3.4 files do not contain data of the new data
types, V3.*-based applications should have no problems accessing them.   

Users of CDF 3.1 or later versions will be able to create CDF files that 
can be read by CDF 2.7.2 or earlier by using the CDFsetFileBackward function 
(in C) or CDF_set_FileBackward subroutine  (in Fortran), or using the
CDF_FILEBACKWARD environment variable on Unix/Linux (including Mac OS X) or 
PC, or CDF$FILEBACKWARD on OpenVMS.  See Section 4.18 of the CDF C 
Reference Manual and the CDF Fortran Reference Manual for details on how to 
create CDF 2.7-compatible files.

All features added to the previous releases are included. Refer to the release 
notes from the previous versions to view the specific features pertaining
to that release.

2. Changes

The following changes have been made/added since CDF V3.4.0:

   * A couple of new data types are added:
     - CDF_INT8: a signed 8-bye integer
     - CDF_TIME_TT2000: also a signed 8-byte integer. This is a new epoch
                        type, which is nenoseconds since J2000 
                        (2000-02-01 12:00:00) with leap seconds included.  
   * A new options added to cdfconvert:
        -[epoch2tt2000 | tt20002epoch | tt20002depoch] 
   * A new tool, cdfleapsecondinfo, is added to show how the leap seconds 
     table is accessed and optionally its table contents.
   * A few new C/Fortran functions are added.
   * A few bugs in the core library were fixed.
   * A few changes were made in skt2cdf and cdfmerge tool programs and help
     info.
   * The Java API for open a CDF file was modified to delay info collection.

3. How to Obtain the Latest Software 

   Go to the CDF home page (http://cdf.gsfc.nasa.gov) and click the
   Download CDF Software link on the left hand side (sidebar).
   

4. Documentation

The CDF documentation set consists of the following:

        cdf341ug.pdf   (CDF User's Guide)
        cdf341crm.pdf  (CDF C Reference Manual)
        cdf341frm.pdf  (CDF Fortran Reference Manual)
        cdf341prm.pdf  (CDF Perl Reference Manual)
        cdf341jrm.pdf  (CDF Java Reference Manual)
        cdf341csrm.pdf (CDF C# Reference Manual)
        cdf341ifd.pdf  (CDF Internal Format Description)

These documents are available from the CDF home page (http://cdf.gsfc.nasa.gov).

We have a user support office for CDF that you can contact when you need an
assistance.  For requests, please send emails to:

  Internet -- gsfc-cdf-support@lists.nasa.gov

Please let us know (via an email to CDFSUPPORT) if you get the distribution.
We would like to know who has the distribution so we know who to contact
when updates are available.

CDFsupport