4 - RISC wars

Abstract

The late 1980s and early 1990s were a very difficult time for both users and suppliers of high-performance reduced instruction set computer (RISC) and complex instruction set computer (CISC) processors. This chapter presents a comparison of RISC and CISC processors. Although RISC had promised to offer faster, cheaper, and less power hungry processors, the established Motorola M68000 and Intel 80×86 families seemed to be able to compete and provide the additional benefit of a vast software base that was already established. It was very difficult for anyone to predict which architecture would dominate and when a change from CISC to RISC should be made. The problem was made even worse by the road maps shown for both the Motorola and Intel CISC architectures showing a never ending supply of MIPS. The main problem for all the RISC purveyors at this time was the fact that no single large computer vendor had endorsed the technology. Many workstation manufacturers had embraced the technology—or several in some cases—but this was not really a sufficient market to support the number of suppliers and the number of different RISC offerings that were present. RISC processors were sold in the tens and hundreds of thousands compared to the millions of M68000 and 8086 processors sold every year. The total sales of all RISC processors during this time period would only equal one month's CISC production. As a result, there was a lot of activity to bring out the next generations of RISC to maintain the performance leadership and thus their competitiveness.