FYI kind regards neil Dr Roger Neil Barton Visiting Research Fellow, Institute of Historical Research http://www.uclmail.net/~neil.barton/ ----- Original Message ----- From: <oxforddnb-lotd@oup.com> To: <ODNBLIFEOFTHEDAY-L@WEBBER.UK.HUB.OUP.COM> Sent: Tuesday, August 11, 2009 12:00 PM Subject: Bringing up Baby - Oxford DNB Life of the Day To read this Life of the Day complete with a picture of the subject, visit http://www.oxforddnb.com/view/lotw/2009-08-11 Kilburn, Tom (1921-2001), computer scientist, was born on 11 August 1921 at 111 Town Street, Soothill Nether, near Dewsbury in Yorkshire, the only son of John William Kilburn, a clerk in a local woollen mill and later company secretary, and his wife, Ivy, nee Mortimer. From 1932 to 1940 he was educated at Wheelwright Grammar School, Dewsbury, where he did well, especially in chemistry and mathematics. He also enjoyed sport, particularly running. His headmaster persuaded him to concentrate on mathematics and, having earned a state scholarship and a county major scholarship, as well as a minor open scholarship, he went to Sidney Sussex College, Cambridge, in 1940. He followed the mathematical tripos, which was restricted under wartime regulations to two years, and was awarded a first class in both part one and part two. In later life he said that the examinations at times seemed very simple because he had a photographic memory, and could readily recall the detail in notes he had taken in lectures. Pioneering work at Malvern and Manchester On completion of his studies at Cambridge, Kilburn was invited to move directly into a post where his skills in mathematics and related disciplines could be of service in the war effort. He was therefore sent on a short City and Guilds course in electronics in London, before being posted to the Telecommunications Research Establishment (TRE), then billeted at Malvern. There he joined F. C. (Freddie) Williams, whose group (working in Malvern School's cricket pavilion) solved hard problems in electronic circuitry in radar and other important areas. Kilburn later enjoyed telling the story of his arrival at TRE, where Williams's disappointment at being given a mathematician rather than a 'proper' electronics expert was barely disguised. However, Kilburn soon established himself in the group and became a key member of the team, making steady progress up through the grades of the scientific civil service. His personal life settled down too, and on 14 August 1943, in a Congregationalist ceremony, he married Irene Marsden (1921-1981), a stores assistant, also from Dewsbury. She was the daughter of Joseph Marsden, a marine dealer. They had a son, John, and a daughter, Anne. During the war and immediately afterwards it was well understood that scientists and mathematicians would benefit greatly from access to some form of general electronic computer. However, no such computer existed. The biggest obstacle to creating a general computer was the lack of a way of storing instructions and data so that access to them could keep up with the speed of the computing circuitry. Williams and Kilburn began to investigate the possibility of using cathode ray tubes (CRTs) to store the information. Early experiments at TRE demonstrated the successful operation of a single-bit memory using the anticipation pulse method, on which a provisional patent was lodged in 1946. The bit was stored in the form of a charge on the phosphor of the CRT screen, and an electron beam could control whether a zero or a one was written. The charge leaked away, however, so it had to be rewritten continuously in order that information could be stored for long periods. This principle of regeneration was still in use more than half a century later. In December 1946 Williams took up the chair of electrotechnics at the University of Manchester and persuaded Kilburn to move with him on secondment from TRE, in order to continue their experimental work on the CRT storage. At this stage, the major challenge was to find a technique to allow large numbers of bits to be held on the CRT in such a way that each bit could be written or read at high speed and would keep its value indefinitely between rewrites. The continuing relationship with TRE was very useful to the project because it meant that Williams and Kilburn had access to a steady supply of parts for use in the circuits they were designing. After carrying out various experiments, including storing 2048 bits, Kilburn in December 1947 completed a report to TRE on his progress. In this he presented a definitive explanation of how a CRT could be used as an electronic storage device. However, Kilburn had not yet demonstrated in practice that a CRT could be used as the storage mechanism for an electronic computer. To achieve that, a test device needed to be built-and the obvious choice was to build a computer. So Kilburn, with the assistance of Geoff Tootill, also on secondment from TRE, designed and built the simplest general purpose computer he could. It had a store size of just 32-bit words, and a very limited instruction set (including subtraction but not addition!), but this sufficed for carrying out any general calculation. The machine, known as the small scale experimental machine (or more affectionately as 'the Baby'), worked successfully for the first time on Monday 21 June 1948. The Baby was the world's first stored-program computer. It was 16 feet long, contained some 650 valves, and weighed half a ton. On that day in 1948, Kilburn not only demonstrated a working stored-program computer for the first time, but also ran the first proper computer program. This program determined the highest factor of a number. The number chosen for the first test was quite small, but within days the machine was able to run the program on 218; it found the correct answer (217) in 52 minutes, having obeyed about 2.1 million instructions with about 3.5 million store accesses. Kilburn was awarded a PhD for his work on the Baby by the University of Manchester in 1948. Further work at Manchester Having completed the project for which he had been seconded from TRE, Kilburn expected to return to Malvern. However, he was persuaded by Williams that he should stay on in Manchester. A major reason for this was that the government had placed a contract with a Manchester-based firm, Ferranti Ltd, to build a full-scale, commercially viable computer to Williams's specification, and Kilburn was the key person needed to lead the design and construction of the prototype. Kilburn therefore accepted a lecturing post at the University of Manchester in 1949 (he was promoted senior lecturer in 1951 and reader in 1955) and increasingly took over the leadership of computer research and development. Kilburn's experience at TRE and when working on the Baby ensured that he approached projects in a very practical way; he understood the value of the engineering prototype and the working model. The work on the new computer was therefore tackled in stages, starting from the original Baby and enhancing and expanding it through a series of working computers. In the process, a number of inventions were incorporated, including the introduction of index (or address modification) registers, and a two-level store based on a number of CRTs and a magnetic drum store. In the late summer of 1949 the ideas demonstrated by the enhanced computer, known as the Manchester mark 1, were transferred to Ferranti as the basis for the computer they produced and marketed in early 1951 as the Ferranti mark 1. Of course, the various stages of the Manchester mark 1 were more than an experiment in computer design; the machine was also available for others to use. One of the earliest users of the evolving Manchester mark 1 was Alan Turing, who came to the mathematics department at the University of Manchester towards the end of 1948. Kilburn continued to lead the computer developments at Manchester. His approach was always one of problem-solving and experimentation, but at the same time he fully recognized the need for practical feedback from real users of the systems that he and his team designed. In the 1950s and 1960s he led the design of further highly innovative computers, each of which, like the mark 1, was exploited commercially. In 1951 he started work on two new computers at the same time. One, called Meg, was really an enhanced mark 1 with floating point arithmetic included, and was probably the world's first floating point computer. This design, with some modification, became the Ferranti Mercury computer, nineteen of which were sold. The other machine, known as the Transistor Machine, was an experiment in the use of transistors for computer design, and was probably the world's first transistor computer. It too was built commercially, this time by Metropolitan Vickers. These successes were followed by the design of possibly the most influential computer produced in Manchester under Kilburn, the Atlas computer. Work on Atlas started in 1956, initially without any government or commercial backing, and progress was slow. However, in 1959 Ferranti agreed to support the project and to provide additional manpower. The goal was to produce a really fast computer which could provide a great deal of computing power for users. The design used the idea of a controlling program (called the supervisor) which would allow the computer to switch between different programs. This meant that when one program was held up (perhaps waiting for input data from a slow peripheral device), the supervisor would allow another program to take over the processing power. A host of other new ideas-some, like virtual memory and the 'compiler compiler', invented in Manchester-were included in the design of the hardware and software of Atlas. A small number of Atlas computers (and its derivatives) were produced, with machines at Manchester, Harwell, London University, and Cambridge doing sterling service supporting the academic and scientific community. In 1966 Kilburn started his final large computer project, the design of a machine called MU5. It introduced new ideas intended to help support the efficient running of system software, such as compilers and operating systems. The machine was a major influence on the 2900 series of computers sold by ICL. Teaching and university administration Kilburn's research focus was always the design of innovative computer systems (as indicated by the fact that he was named as inventor or co-inventor on over seventy-five computer and electronics patents), but he was able to find time to make important contributions too in the educational sphere. In 1960 he became the professor of computer engineering in the electrical engineering department. However, he was aware that the study in depth of the design and application of computer hardware and software was broader than was appropriate for students studying electrical engineering. So in 1964 he established a separate department of computer science. This was the first department in the UK to offer undergraduate degrees in the subject. Kilburn also became increasingly involved in the wider affairs of the university; he served as dean of the faculty of science from 1970 to 1972, and as pro-vice-chancellor from 1976 to 1979. He took early retirement in 1981, with the intention of spending more time with his wife, Irene, who was by that time seriously ill with chronic bronchitis. Tragically, however, she died on 3 August 1981, just before his official retirement. Throughout his career Kilburn received numerous invitations to visit research institutes and research groups in industry in Europe, the USA, and further afield. In practice, however, he accepted very few of these invitations because he disliked travelling and being away from home. He did, however, visit Australia, the USA, and the Russian Academy of Science on two occasions. Wider interests and final years Kilburn was in many ways a typical Yorkshireman. He had clear vision, enormous powers of concentration, and unshakeable determination when he set his mind on something. On the other hand, he was also very quiet and unassuming, and unfailingly polite. He enjoyed pursuits that may be regarded as very ordinary. When his children were young, he and Irene took their holidays in Blackpool, because it provided entertainment for the children and was close enough to Manchester to allow him to return with ease in time for the first football match of the season. He was passionately fond of football and described himself as an avid supporter of Manchester United. He claimed that the day in 1968 when he went to Wembley to watch the team win the European cup was one of the best of his life. He was equally thrilled when they won the treble in 1999 (league championship, FA cup, and European champions cup). He also enjoyed music, mainly jazz, and when he could he would play the piano for his own amusement. In the late 1940s, and for several years thereafter, the University of Manchester led the world in computer design. Kilburn's work was central to this remarkable achievement. His contributions to computer science were recognized nationally and internationally, and he received many honours in his lifetime, including election to the fellowship of the Royal Society in 1965 and appointment as CBE in 1973. He received the Royal Society's royal medal in 1978. One of the most unusual honours, however, was the organization in 1998 by the city of Manchester and the University of Manchester of a major celebration to commemorate the 50th anniversary of the first time the Baby computer worked. Kilburn played a very active part in the events that were arranged, including formally switching on a full-scale working replica of the original computer. He died at Trafford General Hospital, Davyhulme, Manchester, on 17 January 2001, of bronchopneumonia following abdominal surgery. An inquest recorded a verdict of accidental death. He was survived by his son and daughter. Hilary J. Kahn Sources R. B. E. Napper, 'Tom Kilburn (1921-2001)', www.computer50.org/mark1/kilburn.html, accessed 11 Aug 2004 + The Scotsman (22 Jan 2001) + The Times (23 Jan 2001) + The Guardian (23 Jan 2001) + The Independent (23 Jan 2001) + Daily Telegraph (27 Jan 2001) + M. Wilkes and H. J. Kahn, Memoirs FRS, 49 (2003), 283-97 + WW (2001) + personal knowledge (2005) + private information (2005) + b. cert. + m. cert. + d. cert. Archives SOUND BL NSA, North-Western Sound Archive, 1CD0011074 BD24 Likenesses C. Djanogly, bromide print, 1998, NPG · S. Samuels, bromide print, 1999, NPG [see illus.] · J. Morris, two photographs, PA Photos, London · photograph, 1948 (with Freddie Williams), PA Photos, London · photograph, repro. in The Independent · photograph, repro. in The Times · photograph, repro. in The Guardian · photographs, repro. in www.computer50.org/mark1/kilburn.html Wealth at death under £210,000: probate, 1 May 2001, CGPLA Eng. & Wales ======================================================================== © Oxford University Press, 2004. See legal notice: http://www.oup.com/oxforddnb/legal/ We hope you have enjoyed this Life of The Day, but if you do wish to stop receiving these messages, please EITHER send a message to LISTSERV@WEBBER.UK.HUB.OUP.COM with signoff ODNBLIFEOFTHEDAY-L in the body (not the subject line) of the message OR send an email to epm-oxforddnb@oup.com, asking us to stop sending you these messages.