COMPUTER ORGANIZATION AND ARCHITECTURE DESIGNING FOR PERFORMANCE NINTH EDITION
• The family concept: Introduced by IBM with its System/360 in 1964, followed
shortly thereafter by DEC, with its PDP-8. The family concept decouples the
architecture of a machine from its implementation. A set of computers is offered,
with different price/performance characteristics, that presents the same architec-
ture to the user. The differences in price and performance are due to different
implementations of the same architecture.
• Microprogrammed control unit: Suggested by Wilkes in 1951 and introduced
by IBM on the S/360 line in 1964. Microprogramming eases the task of design-
ing and implementing the control unit and provides support for the family
concept.
• Cache memory: First introduced commercially on IBM S/360 Model 85 in
1968. The insertion of this element into the memory hierarchy dramatically
improves performance.
• Pipelining: A means of introducing parallelism into the essentially sequential
nature of a machine-instruction program. Examples are instruction pipelining
and vector processing.
• Multiple processors: This category covers a number of different organizations
and objectives.
• Reduced instruction set computer (RISC) architecture: This is the focus of
this chapter.
When it appeared, RISC architecture was a dramatic departure from the
historical trend in processor architecture. An analysis of the RISC architecture
brings into focus many of the important issues in computer organization and
architecture.