D10) What is the proper way to make backups?

Data and text files, and programs in source form, should be backed up
each time they are modified.  However, the only backups you should
keep of COM, EXE and other *executable* files are the *original*
versions, since if you back up an executable file on your hard disk
over and over, it may have become infected meanwhile, so that you may
no longer have an uninfected backup of that file.  Therefore:
  1. If you've downloaded shareware, copy it (preferably as a ZIP or
other original archive file) onto your backup medium and do not
re-back it up later.
  2. If you have purchased commercial software, it's best to create a
ZIP (or other) archive from the original diskettes (assuming they're
not copy protected) and transfer the archive onto that medium.  Again,
do not re-back up.
  3. If you write your own programs, back up only the latest version
of the *source* programs.  Depend on recompilation to reproduce the
executables.
  4. If an executable has been replaced by a new version, then of
course you will want to keep a backup of the new version.  However, if
it has been modified as a result of your having changed configuration
information, it seems safer *not* to back up the modified file; you
can always re-configure the backup copy later if you have to.
  5. Theoretically, source programs could be infected, but until such
a virus is discovered, it seems preferable to treat such files as
non-executables and back them up whenever you modify them.  The same
advice is probably appropriate for batch files as well, despite the
fact that a few batch file infectors have been discovered.


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