McIDAS allows you to set an environment variable to use gzip data compression during transfers from remote servers to your client workstation. In order to use data compression, your McIDAS-X client workstation and ALL of the remote servers you access must be running McIDAS-X 7.3 or later. In order to use data gzip-compression, they must ALL be running McIDAS-X 2003 or later.

The data gzip-compression feature utilizes the Unix gzip command on the remote server and gunzip command on the client. Gzip-compression is the fastest method of data transfer. These features are most beneficial to users who transfer large data files or those with slow data connections. Before setting the environment variable to enable gzip-compression, it's very important that you verify that ALL the remote servers you access are running v2003 or later.

Compressed data transfers are enabled for all transactions in a McIDAS-X session by defining the Unix environment variable MCCOMPRESS before the session is started. They can also be set on a per invocation basis by specifying the global MCCompress= keyword on the command line.

To enable compressed transfers using gzip, type the following:

Bourne shell, BASH, etc. syntax:

export MCCOMPRESS; MCCOMPRESS=gzip

Csh, Tcsh, etc. syntax:

setenv MCCOMPRESS gzip

See the Unidata McIDAS User's Guide for more information on using compressed data transfers.