programmable read-only memory

from The Free On-line Dictionary of Computing (8 July 2008)

Programmable Read-Only Memory
PROM

   <storage> (PROM) A kind of {ROM} which can be written using a
   PROM programmer.  The contents of each bit is determined by a
   {fuse} or {antifuse}.  The memory can be programmed once after
   manufacturing by "blowing" the fuses, which is an irreversible
   process.  Blowing a fuse opens a connection while blowing an
   antifuse closes a connection (hence the name).  Programming is
   done by applying high-voltage pulses which are not encountered
   during normal operation.

   (1995-04-22)