SAS compress normally refers to options in SAS statements and procedures that control whether SAS produces compressed SAS datasets or not. These options pertain to SAS datasets only. SAS will decompress a compressed SAS dataset transparently in SET, MERGE, and other operations that read SAS datasets.

The GNU compression program, gzip, compresses files. You can use gzip to compress a SAS dataset (for example, prior to ftp'ing it from one server to another) but you will need to decompress it before referring to the SAS dataset in a SAS program. (At least I have not found a way yet to have SAS read a gzip'ped SAS dataset.)

You may find practical uses for both. The Unix OS makes it easy to pipe gip'ped data files (not SAS datasets) through a FILENAME statement to an INPUT statement. In this case a WHERE condition filters data after decompression. In current versions SAS does a better job of handling SAS dataset compression under MS Windows and Unix. Incidentally, advocates of "big iron" computing tell me that transparent compression at the OS level makes gzip and SAS compress options redundant. Sig

-----Original Message----- From: Wilson-Beavers, Linda [mailto:Linda@CAMBIO.ACOMP.USF.EDU] Sent: Friday, February 09, 2001 3:06 PM To: SAS-L@LISTSERV.UGA.EDU Subject: SAS Compress vs GZIP

Does anyone know the differences between using SAS compress and using gzip to save storage space? When would it be more practical to use one or the other?

TIA, Linda