In May 1949, the EDSAC computer, designed and constructed by Maurice Wilkes and his co-workers at the Cambridge University Mathematical Laboratory successfully performed its first, fully automatic computation (Wilkes, 1956, p. 39; 1985, p. 142; Wilkes and Renwick 1949). The machine was demonstrated soon after, in June 1949, at a conference entitled “High Speed Automatic Calculating Machines” held in Cambridge during which tables of squares and primes were printed out (Worsley 1949). As noted in chapter 1 (see the section “The invention of microprogramming: as a case study”), the EDSAC was the very first stored program computer to become fully operational.

The EDSAC was a serial machine in that (1) reading from or writing into main memory was done in a “bit-serial” manner – that is, each bit of a memory word was read or written into one at a time, and (2) the arithmetic unit performed its various operations in a bit-by-bit manner.

Soon after the EDSAC's completion, Wilkes became preoccupied with the issues of regularity and complexity in computer design. This preoccupation is documented not only in his retrospective writings (Wilkes 1985, pp. 184–5, 1986), but also in the early sections of Wilkes (1951), as a preamble to his description of the microprogramming principle. Thus, there is considerable evidence that the development of microprogramming was the outcome of the following problem: