main memory

storage, architecture The storage device used by a computer

to hold the currently executing program and its working data.

A modern computer's main memory is built from random accessmemory integrated circuits. In the old days ferrite corememory was one popular form of main memory, leading to the

use of the term "core" for main memory.

Computers have several other sorts of memory, distinguished by

their access time, storage capicity, cost, and the typical

lifetime or rate of change of the data they hold. Registers

in the CPU are fast, few, expensive and typically change

every few machine instructions. Other kinds are cache,

PROM, magnetic disk (which may be used for virtualmemory), and magnetic tape.

(1996-11-04)