from
The Free On-line Dictionary of Computing (8 July 2008)
main memory
main store
primary storage
<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-access memory} {integrated circuits}. In the old days
{ferrite core memory} 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 {virtual
memory}) and {magnetic tape}.
(1996-11-04)