One way an external CD-ROM may be worthwhile in a machine like
  the 1100FD or HD is text-based CD-ROMS - ones that hold loads of
  information. With it, you have a portable database. *There are
  text-based CD-ROMS that have: encyclopedias, large lists of
  phone numbers, lawyers cases, indexed by docket numbers or last
  names, or whatever, abstracts from magazines [Social Issues
  Resource Service - SIRS - is an amazing text-based database],
  and tons of other things. But yes - temporary files that the
  CD-ROM programs want to create may take up more than a 720K
  floppy disk, although I doubt that it would be a problem, as
  long as the program didn't count on drive C: :-)   via
  https://groups.google.com/d/msg/comp.sys.tandy/fMF9H-2LjMY/hZSPkGuQmHYJ
  comp.sys.tandy