read-only memory

n. (ROM, abbr.) ComputingStorage containing data that can be read but not changed, especially integrated chips and certain compact discs.


Some computer chips and compact discs are examples of read-only memory. For example, most computers contain a boot program in a ROM chip, which contains instructions on how to load the operating system into random access memory (RAM). Originally, ROM chips were programmed during manufacture; they could be read but not updated. The data or instructions in programmable (PROM) and erasable programmable (EPROM) chips can be changed, but they are distinguished from RAM because they retain information after power is turned off.