Great and Big Ideas in Computer Structures

I went to Carnegie Tech after spending my first 6 professional years designing computers at Digital Equipment Corporation to be part of the startup faculty of the computer science department. Allen Newell, Alan Perlis, and Rod Williams, who headed the Electrical Engineering Department, made this career changing choice easy for me. Like everyone who knew Allen, I feel deeply honored to have known him and was influenced by him in many ways. Allen was the most thoughtful, kind, and gentle gentleman I know. His intellect, coupled with his enthusiasm and smile, virtually always led a group in the right direction. He was the role model for a scientist, teacher, husband, father, and person. I cite Allen as "my ideal" when engineers ask me for career advice because Allen maintained a constant enthusiasm for work, and doing science. He saw no higher state of being. We worked together to research and write Computer Structures: Readings and Examples (Bell & Newell, 1971), which was a classic for almost 20 years, or about two hardware generations. We developed the processor-memory-switch (PMS) and instruction-set processor (ISP) notations for describing computers. Although thousands of computers have been introduced since 1971, only a few basically new ideas for computers have emerged since Computer Structures. Our taxonomic frarnework has proved to be equally descriptive of computing alternatives, in-