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Geoff Tootill (4 March 1922 – 26 October 2017)[3] was a noted computer scientist who worked in the Electrical Engineering Department at the University of Manchester with Freddie Williams and Tom Kilburn developing the Manchester Small-Scale Experimental Machine "the world's first wholly electronic stored program computer", popularly known now as the "Baby".[4][1][5][6][2][7][8]

Geoff Tootill
Born (1922-03-04)March 4, 1922
Died October 26, 2017(2017-10-26) (aged 95)
Alma mater University of Cambridge[1]
Known for
Scientific career
Influences Freddie Williams
Tom Kilburn



Tootill attended King Edward's School, Birmingham on a Classics scholarship and in 1940 gained an entrance exhibition to study Mathematics at Christ's College, Cambridge.[1] He was forced to do the course in two years (missing part one of the maths tripos) as his studies were cut short by the war. After the successful operation of the Baby, he was awarded an MSc by the Victoria University of Manchester for his thesis on Universal High Speed Digital Computers: a Small Scale Experimental Machine.


On leaving Cambridge in 1942, Tootill managed to get assigned to work on airborne radar at the Telecommunications Research Establishment (TRE) in Malvern. Here, he went out to airfields to troubleshoot problems with the operation of radar in night fighters, designed modifications and oversaw their implementation. He later said that this was the most responsible job that he had in his life, at the age of just 21.

In 1947, he was recruited by Frederic Calland Williams to join another ex-TRE colleague, Tom Kilburn, at Manchester University developing the world’s first wholly electronic stored program computer. In the UK, three projects were then under way to develop a stored program computer (in Cambridge, the NPL and Manchester) and the main technical hurdle was the memory technology. In order to test the cathode ray tube memory designed by FC Williams when it was constructed, Kilburn and Tootill designed an elementary computer, officially known as the Small-Scale Experimental Machine, but better known as “Baby”. The computer could store 32 instructions or numbers using a single CRT. On 21st June, 1948, after months of patient work constructing and testing the SSEM piece by piece, coping with the unreliable electronic components of the day, the machine finally ran a routine written by Kilburn[9] (they didn't use the word "program" then) to find the highest proper factor of a number. In Tootill's words "And we saw the thing had done a computation".[10]. A day or two later, the SSEM ran successfully for 52 minutes to find the highest proper factor of 218, which required c. 3.5m arithmetic operations.

During the development of Baby, the team used to speculate on how the computer would be used for real work: weather forecasting, atomic research etc. They thought that only the government would need computers in the UK, maybe 2 or 3, but in America they might need as many as half a dozen! They could not have foreseen how their invention would change the world.

After the SSEM’s first operation in June 1948, Alan Turing moved to Manchester so he could use the SSEM for a project that he was working on at the National Physical Laboratory, where they had also been working on developing a computer. Tootill instructed Turing on use of the Baby and debugged a program Turing had written to run on the SSEM[11].

In 1949, Tootill joined Ferranti where he developed the logic design of the first commercial computer (which was based on the SSEM). He stayed at Ferranti only briefly and later the same year, he joined the Royal Military College of Science at Shrivenham as a Senior Lecturer on a considerably higher salary, lecturing and leading lab studies on digital computing.

In 1956, Tootill joined the Royal Aircraft Establishment, Farnborough, researching issues for air traffic control systems. Here he wrote, with Stuart Hollingdale, "Electronic Computers", Penguin 1965, which ran through eight printings and was translated into Spanish and Japanese. Tootill was also a founding member of the British Computer Society in 1956.[1]

In 1963, Tootill joined the newly formed European Space Research Organisation (ESRO, now the European Space Agency), working in France, Holland and then Germany. Here he set up and directed the Control Centre of ESRO, with ground stations in Belgium, Spitsbergen, Alaska and the Falklands. He was a fluent French speaker and spoke passable German. For the International Federation for Information Processing, Tootill was Chairman of the drafting committee of its "Vocabulary of Information Processing", North Holland Publishing Company 1966, on which various national and international standards were based.

In 1969, Tootill rejoined the UK Civil Service and was assigned to a bureaucratic post in London, which he did not enjoy.

In 1973, he joined the National Physical Laboratory at Teddington, where he developed communications standards for the European Informatics Network – this was an experimental computer internetwork which was an early example of technologies now used in the Internet. He was seconded for a time to the National Maritime Institute, Feltham working on collision avoidance and computer-aided design for ship hulls.

Tootill retired in 1982, but remained active by helping set up and run a computer group for the Wokingham branch of U3A (University of the Third Age).

In 1997, drawing on his linguistics background (notably Latin, Greek, French and German), he designed a phonetic algorithm for encoding English names[12] (to recognise that e.g. Deighton and Dayton, Shore and Shaw sound the same) which garnered over 2,000 corporate users as part of a data matching package developed by his son Steve.

In 1998, the Computer Conservation Society (in a project led by Christopher P Burton) unveiled a replica of the SSEM (which is now in the Museum of Science and Industry (Manchester)) to commemorate the 50th anniversary of the running of the first electronically stored program, based in large part on Tootill’s notes and recollections. A page from his June 1948 notebook details the code of the first ever software program, written by Tom Kilburn[13].

Personal lifeEdit

As a boy, Tootill was keenly interested in electronics. He built a radio that he used to fall asleep at night listening to, until his mother told him he must switch it off before going to sleep. He solved this by devising a sleep timer using an an old alarm clock and a piece of string from the trembler to the switch.

Tootill met Pamela Watson while in Malvern during the war, where they were both members of the ‘Flying Rockets Concert Party’ which used to tour surrounding villages. Using techniques learned in the TRE lab, Tootill automated stage lighting for the productions and helped write and appeared in sketches.

He and Pam were married in 1947 and had three sons, Peter, Colin and Stephen and two grandchildren, Mia and Duncan.

On moving to the RAE, Farnborough in 1956, Tootill had a house built to his and his wife's own design in a new development. Before the road was surfaced, Tootill laid a cable under it to a neighbour’s house, so that he could install a two-way baby alarm connecting the houses.

Mr & Mrs Tootill were active members of the RAE Operatic Society and The Savoy Singers, singing in the chorus of many productions. The Tootill family travelled extensively around the UK and Europe in a caravan in the 50’s and 60’s.

Pam died from heart disease in 1979. In 1981, Tootill married Joyce Turnbull, who survived him. He lived in retirement with Joyce in Wokingham until 2015 when she moved to a care home, suffering from severe Alzheimer's.