netCDF 3.6.0-beta6 with Large File Support

• To: netcdfgroup@xxxxxxxxxxxxxxxx
• Subject: netCDF 3.6.0-beta6 with Large File Support
• From: Russ Rew <russ@xxxxxxxxxxxxxxxx>
• Date: Thu, 14 Oct 2004 10:23:43 -0600

Hi,

A new beta release of netCDF-3.6.0 is available for external testing:

  ftp://ftp.unidata.ucar.edu/pub/netcdf/netcdf-beta.tar.gz

Simplified installation instructions for the beta release are
available from:

  http://www.unidata.ucar.edu/packages/netcdf/INSTALL-beta/

Although we have tested this release extensively and believe it is a
candidate for final release, we would appreciate feedback on any
problems you might discover.

NetCDF version 3.6 improves large file support, Windows compatibility,
ease of installation, and performance using the Fortran-90 interface.
In addition, it fixes a few bugs.

In previous releases it was possible to create netCDF files that
exceeded 2 GiB by observing fairly severe constraints on the structure
of the data.  For example, you could use a very large fixed-size
variable as the last variable, or you could use the record dimension
for large variables and use a large number of records.  Such
restrictions were necessary due to the use of 32-bit fields in the
netCDF format for offsets pointing to the beginning of data for each
variable.

Version 3.6 introduces a new variant of the netCDF file format, while
preserving backward compatibility with the existing format.  The new
variant has 64-bit fields for file offsets, removing many of the size
constraints for netCDF files.  Greg Sjaardema of Sandia Labs
contributed C library code to support 64-bit offsets, and we added
changes to increase the maximum variable and record size, to permit
use from Fortran, C++, and Java interfaces, to support creation of
large files with the ncgen utility, and to check declared variable
shapes for conformance with remaining size constraints.  The new
library will access data transparently in both the classic and 64-bit
offset formats.

Version 3.6 is configured to use Large File Support by default if
available on the target platform.  Building and installing from source
has been simplified so that there is no need to set environment
variables on most platforms.

We are maintaining a list of questions and answers for netCDF large
file support:

  http://www.unidata.ucar.edu/packages/netcdf/faq-lfs.html

More information about the 3.6.0-beta release is contained in the
RELEASE_NOTES: 

  http://www.unidata.ucar.edu/packages/netcdf/release-notes-3.6.0-beta6

or the new draft documentation:

  http://www.unidata.ucar.edu/packages/netcdf/docs/netcdf/index.html

If you have other questions or encounter problems with the beta
release, please contact support@xxxxxxxxxxxxxxxx.  Thanks!

-- Russ Rew
-- Ed Hartnett