Designing a computer is a complex task that requires the designers to achieve a certain desired performance level while staying within cost and time constraints. This process has many aspects, some of the most significant being instruction set design, logic design, functional organization, and implementation. Implementation includes problems of physical engineering: integrated circuit design, optimization of power consumption, cooling, and the like. To create a functional design that will be viable in the marketplace is a difficult task requiring attention to all these issues and more.

Classically, the term computer architecture referred solely to instruction set design--that is, the design of those commands that run the machine at its most basic level. Everything else was grouped under the rubric of implementation, implying that theoretical design was somehow more important or satisfying than the addressing of practical concerns. Recently this attitude has altered, and now it is...