Baby

The modern computer age began on 21 June 1948, when the first electronic universal stored-program computer successfully ran its first program. Built in Manchester, this ancestral computer was the world’s first universal Turing machine in hardware. Fittingly, it was called simply ‘Baby’. The story of Turing’s involvement with Baby and with its successors at Manchester is a tangled one. The world’s first electronic stored-program digital computer ran its first program in the summer of 1948 (Fig. 20.1). ‘A small electronic digital computing machine has been operating successfully for some weeks in the Royal Society Computing Machine Laboratory’, wrote Baby’s designers, Freddie Williams and Tom Kilburn, in the letter to the scientific periodical Nature that announced their success to the world. Williams, a native of the Manchester area, had spent his war years working on radar in rural Worcestershire. Kilburn, his assistant, was a bluntspeaking Yorkshireman. By the end of the fighting there wasn’t much that, between them, they didn’t know about the state of the art in electronics. In December 1945 the two friends returned to the north of England to pioneer the modern computer. Baby was a classic case of a small-scale university pilot project that led to successful commercial development by an external company. The Manchester engineering firm Ferranti built its Ferranti Mark I computer to Williams’s and Kilburn’s design: this was the earliest commercially available electronic digital computer. The first Ferranti rolled out of the factory in February 1951. UNIVAC I, the earliest computer to go on the market in the United States, came a close second: the first one was delivered a few weeks later, in March 1951. Williams and Kilburn developed a high-speed memory for Baby that went on to become a mainstay of computing worldwide. It consisted of cathode-ray tubes resembling small television tubes. Data (zeros and ones) were stored as a scatter of dots on each tube’s screen: a small focused dot represented ‘1’ and a larger blurry dot represented ‘0’. The Williams tube memory, as the invention was soon called, was also used in Baby’s immediate successors, built at Manchester University and by Ferranti Ltd.