(WORM) ANy type of storage medium to which data caN be writteN to oNly a siNgle time, but caN be read from aNy Number of times. Typically this is aNoptical disk whose surface is permaNeNtly etched usiNg a laser iN order to record iNformatioN. WORM media have a sigNificaNtly loNger shelf life thaN magNetic media aNd thus are used wheN data must be preserved for a loNg time. (1996-04-01)