COMPRESSION techniques under CP/M have not evolved quite as fast as they
have for other platforms.

The older methods involved individual file compression and then LIBRARY
to contain the group of files.

EXTENSION       COMMENTS
---------       --------
LBR             Library - a method of containning files, no compression.
                          Create with NULU or LAR (various revisions)
                          Dissolve with NULU or DELBR.
?Q?             Squeeze - individual file compression technique.
                          Create with SQUEEZE, dissolve with UNSQUEEZE.
                          The utilities names may vary, but the files
                          description should help.
?Z?             Crunch -  Individual file compression technique.
                          Create with CR, CRUNCH, various versions.
                          Dissolve with UNCR, UNCRUNCH, various versions.
?Y?             LZH-CRUNCH - Individual file compression technique.
                          Create with CRLZH20 and dissolve with UCRLZH20.

Newer Methods are true archivers.  These utilities can both compress and
contain a group of files.

ARC           Archive - A true archiver.  Files can be handled across
                        different platforms.
ARK           Archive - default name for ARC under CP/M.  
ZIP           Zip     - A true archive.  No utility to create under CP/M,
                        the older versions of ZIP files can be dissolved
                        with UNZIP (various versions)
LZH           LZH     - A true archiver.  Create with LHARC and dissolve
                        with LHARD.  The CP/M version cannot handle LH5
                        compression techniques.
ARJ           Arj     - A true archive.  No utility to create under CP/M,
                        the older versions of ARJ files can be dissolved
                        with UNARJ.
PMA           PMA     - A true archiver.  Available for CP/M only.
                        PMAUTOAE.COM is the self dissolving file to
                        look for.  This utility creates the best 
                        compression available under CP/M.  It also
                        has the ability to make self-dissolving-files,
                        that are archives.  NOTE: has the ability to
                        dissolve LH5 LZH archives created by other
                        platforms.