                       DATA COMPRESSION HINTS
                     submitted by: Gloria Short

  Here are some rules of thumb to help you live with disk
  compression.

  Be sure to back up your data before installing a hard disk
  compression product. Also, be sure to back up your data before
  you uninstall the compressed drive, since chances of errors are
  magnified as the program decompresses megabyte upon megabyte of
  data.

  If you're using DOS 6, either with DoubleSpace or with any other
  compression product, turn off SMARTDrive's lazy write feature.
  When DOS 6 is installed, SMARTDrive is set up so that it will not
  always write data to disk immediately, but will wait for an
  opportune moment. It's possible to lose data if you just switch
  off your computer.

  If you have additional drives on your system, such as a removable
  hard disk or a CD-ROM drive, don't expect the compression program
  to have the intelligence to figure it all out. You might have to
  go back and let your programs know the lay of the land. (My
  CD-ROM drive was changed from drive E to drive F during
  compression installation.)

  Be sure to have all of your manuals handy during installation.
  During each of my installations on two different computers (a 386
  and a 486), I had problems. They were minor--not fatal--but
  having the manuals handy let me track down some of the more
  esoteric ones (such as losing my 386 enhanced driver for
  Windows).

  Be aware that not all games will work in compressed form. If
  you're a serious game player, it might be a good idea to make a
  drive partition, creating an uncompressed logical drive for your
  games, and compress only your more standard applications and
  files.

  If you have a removable hard drive, compressing one of the
  cartridges makes for an extremely simple backup option. I used a
  90MB removable compressed to nearly 180MB for easy whole-disk
  backups. In Windows, I created a macro that drags the C drive
  over to my removable and copies the entire thing in roughly 15
  minutes.

  When you see an indication of how much free space is left on a
  disk, assume that it's an educated guess rather than the actual
  truth, since different files compress at different rates. In one
  instance, Windows' File Manager told me I had 229MB free, the
  compression program's utility informed me that I had 210MB free,
  and DOS informed me that I actually had 234MB free.

  Don't use a standard disk optimizer on a compressed drive.
  Chances are that it won't hurt anything, but it will see the
  entire compressed drive as a single file. Use an optimizer
  designed for compressed disks.

  Copying a file (or moving a directory in Windows) within a
  compressed disk takes longer than copying that file to an
  uncompressed disk because the file must be decompressed and then
  recompressed.

  A hard disk compression utility is a perfect addition to a roving
  laptop computer. Consider a utility that will allow compressed
  floppies to be used on other systems for maximum efficiency.

  A compressed file can rarely be compressed further. Sometimes you
  can achieve an additional percentage or two of compression, but
  usually a compressed file actually becomes larger when compressed
  a second time. For this reason, one of the techniques for saving
  space on an uncompressed hard drive--using PKZIP to compress
  large files and directories--is useless on a drive compressed
  with Stacker or one of its competitors.
