by David M. Yates
© Oxford University Press 2004 All rights reserved
Davies, Donald Watts (1924-2000), computer scientist, was born on 7 June 1924 at 102 Dumfries Street, Treorci, Glamorgan, with a twin sister; they were the only children of John Watts Davies (1899-1925), a colliery pay clerk, and his wife, Hilda, née Stebbens (1900-1988). When John Davies died, his young widow returned with the twins to her home town of Portsmouth, where they lived with her mother and sister. At Portsmouth's Southern Secondary School for Boys Donald's progress was unremarkable up to the age of fifteen, but then his talent for mathematics and science suddenly flowered, and after a wartime two-year course in physics at Imperial College, London, he was awarded his BSc degree with first-class honours in 1943.
Davies then joined a group at Birmingham University under Professor Rudolf Peierls, working on the design of a uranium 235 separation plant, part of the atomic weapons project code-named Tube Alloys; his supervisor was the later notorious Klaus Fuchs. The separation plant was developed by Imperial Chemical Industries (ICI) in Billingham, and after the end of the war he continued working on various projects for ICI and at Birmingham University, before deciding in 1946 to use the remaining third year of his state scholarship by returning to Imperial College to study mathematics. This led to another first-class BSc degree, and he was awarded the Lubbock memorial prize as the leading mathematician of his year at London University in 1947. During this year he heard about the current early development of computers from a lecture by John Womersley of the National Physical Laboratory (NPL). Excited by the potential of this new technology, he applied successfully to join the NPL group, and moved to Teddington in September 1947. There he worked briefly with Alan Turing, whose remarkable pioneering plans for a computer to be called the ACE had not yet been realized because of a lack of staff with appropriate skills in digital electronics. In 1948, after Turing's departure, his group was reconstructed as a balanced team of mathematicians and engineers including Davies, J. H. Wilkinson, and E. A. Newman, led by F. M. Colebrook. The result was the successful Pilot ACE computer which ran its first program on 10 May 1950, one of the first four or five electronic stored-program digital computers in the world.
Recommending Davies for a Commonwealth Fund fellowship in 1954, Colebrook wrote:
During the 1950s Davies turned his attention from computer design to applications, developing a road traffic simulator for Pilot ACE, and in 1958 initiating a project to use full-scale ACE to translate technical Russian into English. In 1963 he was appointed technical manager of the advanced computer techniques project, responsible for government support for the UK computer industry.
With a technical ability matched by growing organizational skills, Davies made rapid progress through the grades of the scientific civil service. In 1966 he succeeded Albert Uttley as superintendent of NPL's autonomics division, and soon turned it into a division of computer science with new and more practical objectives. His flagship project was based on an idea he had originated in 1965: that to achieve efficient communication between computers a fast message-switching communication service was needed in which long messages were split into chunks sent separately to minimize the risk of congestion. These chunks he called packets and the technique became known as packet-switching. His network design was received enthusiastically by the US Advanced Research Project Agency (ARPA), and the Arpanet and the NPL local network became the first two computer networks in the world using the technique. The internet can be traced back directly to this origin.
In 1979 Davies was able to relinquish most of his managerial responsibilities to concentrate on technical work. Realizing that computer networks would be used widely only if techniques could be developed to combat malicious interference, he started a group to work on data security, concentrating on the new method of public key cryptosystems. The group built a strong consultancy role around his expertise; all the major UK clearing banks, for instance, used their services. He retired from NPL in June 1984, but continued his work as a data security consultant, travelling widely and acting as an expert witness in court cases involving computer security and credit card fraud.
Davies's contributions to UK computer development, in particular his work on packet-switching, were recognized by the British Computer Society, who gave him their John Player award in 1974 and a distinguished fellowship in 1975; he also became their technical vice-president in 1983. He was appointed CBE in 1983, fellow of the Royal Society in 1987, and visiting professor at Royal Holloway and Bedford New College in 1987, and received an honorary DSc from the University of Salford in 1989. He was author or joint author of four influential books in his areas of expertise, notably Computer Networks and their Protocols (1973), and over 140 technical reports and papers. He was a first-rate public speaker, confident and expert with a lively incisive style.
His versatility and his fascination with intellectual challenges and puzzles are evident in Davies's private interests as well as in his official work. Over the years these interests included: the design and construction of noughts-and-crosses machines, which in the days before home computers were considerable attractions at the annual NPL children's parties (this game was the subject of his first published paper, in 1950); historic cryptographic machines, particularly the German machines of the Second World War; ball lightning; and all puzzles and games capable of mathematical analysis. His last project showed that his technical skills remained undiminished: he developed for fun a simulator of the Pilot ACE for a modern personal computer. Although a confirmed workaholic, regularly bringing his secretary on Monday mornings a pile of tapes he had dictated over the weekend, Davies had many intellectual interests outside work: after his retirement from NPL he took annual Open University courses in various subjects including astronomy, human biology, oceanography, and the history of art. He enjoyed music, mainly classical, and the extensive opportunities for world travel offered by his lecturing and consultancy work. He died at the Princess Alice Hospice, Esher, Surrey, from malignant melanoma, on 28 May 2000, and was cremated at Leatherhead crematorium on 6 June. He was survived by his wife and their three children.
DAVID M. YATES
Sources
The Times (31 May 2000)
D. M. Yates, Turing's legacy: a history of computing at the National Physical Laboratory, 1945-1995 (1997)
personal knowledge (2004)
private information (2004)
M. Campbell-Kelly, 'Data communications at the National Physical Laboratory', Annals of the History of Computing, 9 (1988), 221-47
M. Campbell-Kelly, The Independent (7 June 2000)
J. Schofield, The Guardian (2 June 2000)
b. cert.
m. cert.
d. cert.
b. cert. [John Watts Davies, father]
b. cert. [Hilda Stebbens, mother]
d. cert. [John Watts Davies, father]
d. cert. [Hilda Davies, mother]
Archives
SOUND Sci. Mus., 'D. W. Davies', Pioneers of computing, undated, tape no. 1 in a series of interviews with computer pioneers recorded in the late 1970s
Likenesses
photograph, 1966, National Physical Laboratory, Teddington, Middlesex
Wealth at death
£269,459--gross; £267,246--net: probate, 8 May 2001, CGPLA Eng. & Wales
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