From René Witte:
PenguinBackup is a single, bootable 3.5" floppy disk which includes a complete operating system, utilities, and communication software for all kinds of Pilots (OS 1.x - 3.x), wrapped in a nice, easy-to-use menu system.
It is intended as an emergency backup system in case you're on the road with only your Pilot and need to do a full restore after a hard reset.
You only need to carry the PenguinBackup floppy (and a second one holding the programs/data to restore) and can bring your Pilot back to life with almost any plain ol' PC without the need to install anything on it (it doesn't even need a hard drive).
You can also use it to do full backups on the road or install new applications/databases (e.g. store some books in Doc format on a floppy and install them one after the other to have something to read :-)