There are three ADDE data transfer methods available for sending data from remote servers to your client workstation. The methods are gzip-compressed, compressed, and uncompressed.
The gzip-compressed and compressed methods are most beneficial to users who transfer large data files or those with slow data connections. However, they only reduce the amount of data during the transfer; they do not change the resultant file size or accounting (the byte counts remain the same). For example, the destination file size from an IMGCOPY command is the same no matter which of the three methods you use. If most of the datasets you access are on a local network with fast transfer rates, then using the uncompressed method is probably best because it minimizes overhead.
The data transfer method you use on your client workstation is determined by the setting of its MCCOMPRESS environment variable. Because it's an environment variable, the method you select is the default for the entire McIDAS-X session. The only way to change the default method is to exit your McIDAS-X session, change the setting of MCCOMPRESS, then restart McIDAS-X. To override the default setting on a command-by-command basis, use the MCCOMPRESS global keyword with any ADDE command. See Appendix A, Global Keywords for more information.
If MCCOMPRESS is not set on your client workstation, or if it's set to NONE, then the uncompressed data transfer method is used. If you want to use the compressed data transfer method, enter the following Unix command (substitute the equivalent if using C shell) on your client workstation.
If you want to use the gzip-compressed data transfer method and you've verified that your client workstation and all the remote servers it accesses are running McIDAS-X 2003 or later, enter the following Unix command (substitute the equivalent if using C shell) on your client workstation.
The environment variable will be set each time you log on to your account if you have setup your enviornment definition file (e.g., .cshrc for C-like shells, .profile for SH-like shells, and .bash_profile for BASH) to source the appropriate user (user or 'mcidas') definition file included in Unidata McIDAS: ~mcidas/admin/user_env.(sh|csh) for the users other than 'mcidas' and ~mcidas/admin/mcidas_env.(sh|csh) for the user 'mcidas'.