A special floppy disk that is required in order to perform some task.
Some contain special coding that allows an application to identify it
uniquely, others are special code that does something that
normally-resident programs don't or can't. (For example, AT&T's "Unix
PC" would only come up in {root mode} with a special boot disk.) Also
called a key disk. See {dongle}.
[glossary]
[Reference(s) to this entry by made by: {dongle}]