Appendix A. Baby’s Conception: The Back Story

What ideas, and what people, lay behind the design of the small Manchester University computer called Baby that first ran a program on 21st June 1948? The story begins in the autumn of 1945 and embraces influences from Bletchley Park mathematicians, from John von Neuman’s group at Princeton University, from engineers at the government’s Telecommunications Research Establishment and from Alan Turing’s activities at the National Physical Laboratory. Some of these influences were stronger than others but none had quite as much practical significance as the seminal work of two engineers, F. C. Williams and Tom Kilburn, who devised the first practical RAM—a random-access memory capable of working at electronic speeds. In this chapter we analyse all the influences chronologically, enabling us to show that the Manchester computer’s general architecture was close to that of the machine being designed at Princeton University but that the detailed hardware implementation was unique to Manchester. From this small beginning grew the family of Ferranti Mark I and Mark I* computers.