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Read-Only Memory

Another form of non-volatile random access storage is the read-only memory (ROM). Here a single memory bit is nothing more than a connection that is either open or closed. The most common ROM types are known as field-programmable (as opposed to factory programmable). This programming process consists of stepping through all the bits and setting the necessary ones by burning open the fuse-like material associated with that bit.

There are many varieties of field-programmable ROM units:

PROM - programmable read-only memory,
EPROM - erasable PROM (using ultraviolet light), and
EEPROM (E PROM) - electrically erasable PROMs.

The most common uses of ROM memory in a computer are to provide initialization such as memory tests and disk bootstrapping.

Doug Gingrich
Tue Jul 13 16:55:15 EDT 1999