Donald Watts Davies, (7 June 1924 – 28 May 2000) was a Welsh
computer scientist
A computer scientist is a person who is trained in the academic study of computer science.
Computer scientists typically work on the theoretical side of computation, as opposed to the hardware side on which computer engineers mainly focus (al ...
who was employed at the UK
National Physical Laboratory (NPL).
In 1965 he conceived of
packet switching, which is today the dominant basis for data communications in
computer networks worldwide. Davies proposed a commercial national data network in the United Kingdom and designed and built the local-area
NPL network to demonstrate the technology. Many of the wide-area packet-switched networks built in the 1970s were similar "in nearly all respects" to his original 1965 design. The
ARPANET project credited Davies for his influence, which was key to the development of the
Internet.
Davies' work was independent of the work of
Paul Baran in the United States who had a similar idea in the early 1960s, and who also provided input to the ARPANET project, after his work was highlighted by Davies' team.
Early life
Davies was born in
Treorchy in the
Rhondda Valley,
Wales. His father, a clerk at a coalmine, died a few months later, and his mother took Donald and his twin sister back to her home town of
Portsmouth, where he went to school.
[The History of Computing Project – Donald Davies Biography](_blank)
/ref> He attended the Southern Grammar School for Boys.
He received a BSc degree in physics (1943) at Imperial College London, and then joined the war effort working as an assistant to Klaus Fuchs
Klaus Emil Julius Fuchs (29 December 1911 – 28 January 1988) was a German theoretical physicist and atomic spy who supplied information from the American, British and Canadian Manhattan Project to the Soviet Union during and shortly aft ...
on the nuclear weapons Tube Alloys project at Birmingham University. He then returned to Imperial taking a first class degree in mathematics (1947); he was also awarded the Lubbock memorial Prize as the outstanding mathematician of his year.
In 1955, he married Diane Burton; they had a daughter and two sons.
Career history
National Physical Laboratory
From 1947, he worked at the National Physical Laboratory (NPL) where Alan Turing was designing the Automatic Computing Engine (ACE) computer. It is said that Davies spotted mistakes in Turing's seminal 1936 paper ''On Computable Numbers'', much to Turing's annoyance. These were perhaps some of the first "programming" bugs
Bugs may refer to:
* Plural of bug
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in existence, even if they were for a theoretical computer, the universal Turing machine. The ACE project was overambitious and floundered, leading to Turing's departure. Davies took over the project and concentrated on delivering the less ambitious Pilot ACE computer, which first worked in May 1950. A commercial spin-off, DEUCE
Deuce, Deuces, or The Deuce may refer to:
Arts and entertainment Fictional characters
* Deuce, in the '' Danger Girl'' comic book series
* Deuce, a character in ''Shake It Up''
* Deuce, in the '' Wild Cards'' science fiction universe
* Deuce Bi ...
was manufactured by English Electric Computers and became one of the best-selling machines of the 1950s.
Davies also worked on applications of traffic simulation and machine translation. In the early 1960s, he worked on government technology initiatives designed to stimulate the British computer industry.
Packet switching
In 1965, Davies developed the idea of packet switching, dividing computer messages into packets that are routed independently across a network, possibly via differing routes, and are reassembled at the destination.
Davies used the word "packets" after consulting with a linguist because it was capable of being translated into languages other than English without compromise. Davies' key insight came in the realisation that computer network traffic was inherently "bursty" with periods of silence, compared with relatively constant telephone traffic. He designed and proposed a commercial national data network based on packet switching in his 1966 ''Proposal for the Development of a National Communications Service for On-line Data Processing''.
In 1966 he returned to the NPL at Teddington just outside London, where he headed and transformed its computing activity. He became interested in data communications following a visit to the Massachusetts Institute of Technology, where he saw that a significant problem with the new time-sharing computer systems was the cost of keeping a phone connection open for each user. Davies was the first to describe the concept of an "Interface computer", in 1966, today known as a router. He and his team were one of the first to use the term 'protocol' in a data-commutation context in 1967. The NPL team also carried out simulation work on packet networks, including datagram networks.
His work on packet switching, presented by his colleague Roger Scantlebury, initially caught the attention of the developers of ARPANET, a US defence network, at the Symposium on Operating Systems Principles in October 1967. In Scantlebury's report following the conference, he noted "It would appear that the ideas in the NPL paper at the moment are more advanced than any proposed in the USA". Larry Roberts of the Advanced Research Projects Agency in the United States applied Davies' concepts of packet switching in the late 1960s for the ARPANET, which went on to become a predecessor to the Internet. These early years of computer resource sharing were documented in the 1972 film '' Computer Networks: The Heralds of Resource Sharing''.
Davies first presented his own ideas on packet switching at a conference in Edinburgh on 5 August 1968. At NPL Davies directed the development of a local-area packet-switched network, the ''Mark I NPL network''. It was replaced with the ''Mark II'' in 1973, and remained in operation until 1986, influencing other research in the UK and Europe, including Louis Pouzin's CYCLADES project in France.
Unbeknown to him, Paul Baran of the RAND Corporation
The RAND Corporation (from the phrase "research and development") is an American nonprofit global policy think tank created in 1948 by Douglas Aircraft Company to offer research and analysis to the United States Armed Forces. It is financed ...
in the United States was also working on a similar concept; when Baran became aware of Davies's work he acknowledged that they both had equally discovered the concept. Baran was happy to acknowledge that Davies had come up with the same idea as him independently. In an e-mail to Davies, he wrote
Leonard Kleinrock, a contemporary working on analysing message flow using queueing theory, developed a theoretical basis for the operation of message switching networks in his PhD thesis during 1961-2, published as a book in 1964. However, Kleinrock's later claim to have developed the theoretical basis of packet switching networks is disputed by other Internet pioneers, including by Robert Taylor, Baran and Davies. Davies and Baran are recognized by historians and the U.S. National Inventors Hall of Fame for independently inventing the concept of digital packet switching used in modern computer networking including the Internet.
Internetworking
Davies, along with his deputy Derek Barber and Roger Scantlebury, conducted research into protocols for internetworking. They participated in the International Networking Working Group from 1972, initially chaired by Vint Cerf and later Derek Barber. Davies and Scantlebury were acknowledged by Bob Kahn and Vint Cerf in their 1974 paper on internetworking, ''"A Protocol for Packet Network Intercommunication''".
Davies and Barber published "Communication networks for computers" in 1973. They spoke at the Data Communications Symposium in 1975 about the "battle for access standards" between datagrams and virtual circuits
A virtual circuit (VC) is a means of transporting data over a data network, based on Packet switching, packet switching and in which a connection is established within the network between two endpoints. The network, rather than having a fixed dat ...
, with Barber saying the "lack of standard access interfaces for emerging public packet-switched communication networks is creating 'some kind of monster' for users". For a long period of time, the network engineering community was polarized over the implementation of competing protocol suites, a debate commonly called the ' Protocol Wars'. It was unclear which type of protocol would result in the best and most robust computer networks. Internetworking experiments at NPL under Davies included connecting with the European Informatics Network by translating between two different host protocols and connecting with the Post Office Experimental Packet Switched Service using a common host protocol in both networks. Their research confirmed establishing a common host protocol would be more reliable and efficient than translating between different host protocols using a gateway. Davies and Barber published "Computer networks and their protocols" in 1979.
Computer network security
Davies relinquished his management responsibilities in 1979 to return to research. He became particularly interested in computer network security A network security policy (NSP) is a generic document that outlines rules for computer network access, determines how policies are enforced and lays out some of the basic architecture of the company security/ network security environment. The docume ...
. Together with David O. Clayden, he designed the Message Authenticator Algorithm (MAA) in 1983, one of the first message authentication code
In cryptography, a message authentication code (MAC), sometimes known as a ''tag'', is a short piece of information used for authenticating a message. In other words, to confirm that the message came from the stated sender (its authenticity) and ...
algorithms to gain widespread acceptance. It was adopted as international standard ISO 8731-2 in 1987.
He retired from NPL in 1984, becoming a leading consultant on data security to the banking industry and publishing a book on the topic that year.
Later career
In 1987, Davies became a visiting professor at Royal Holloway and Bedford New College.
Awards and honours
Davies was appointed a Distinguished Fellow of the British Computer Society
Sir Maurice Wilkes served as the first President of BCS in 1957
BCS, The Chartered Institute for IT, known as the British Computer Society until 2009, is a professional body and a learned society that represents those working in infor ...
(BCS) in 1975 and was made a CBE in 1983, and later a Fellow of the Royal Society in 1987.
He received the John Player Award from the BCS in 1974. and was awarded a medal by the John von Neumann Computer Society in Hungary in 1985.
In 2000, Davies shared the inaugural IEEE Internet Award. In 2007, he was inducted into the National Inventors Hall of Fame, and in 2012 Davies was inducted into the Internet Hall of Fame by the Internet Society.
NPL sponsors a gallery, opened in 2009, about the development of packet switching and "Technology of the Internet" at The National Museum of Computing.
A blue plaque
A blue plaque is a permanent sign installed in a public place in the United Kingdom and elsewhere to commemorate a link between that location and a famous person, event, or former building on the site, serving as a historical marker. The term i ...
commemorating Davies was unveiled in Treorchy in July 2013.
Family
Davies was survived by his wife Diane, a daughter and two sons.
See also
* History of the Internet
* Internet in the United Kingdom § History
* Internet pioneers
Books
*
*
* with W. Price, D. Barber, C. Solomonides
*
References
External links
Oral history interview with Donald W. Davies
Charles Babbage Institute, University of Minnesota. Davies describes computer projects at the UK National Physical Laboratory, from the 1947 design work of Alan Turing to the development of the two ACE computers. Davies discusses a much larger, second ACE, and the decision to contract with English Electric
N.º UIC: 9094 110 1449-3 (Takargo Rail)
The English Electric Company Limited (EE) was a British industrial manufacturer formed after the Armistice of 11 November 1918, armistice of World War I by amalgamating five businesses which, during th ...
Company to build the DEUCE
Deuce, Deuces, or The Deuce may refer to:
Arts and entertainment Fictional characters
* Deuce, in the '' Danger Girl'' comic book series
* Deuce, a character in ''Shake It Up''
* Deuce, in the '' Wild Cards'' science fiction universe
* Deuce Bi ...
—one of the first commercially produced computers in Great Britain.
Biography
from th
History of Computing Project
Donald Davies profile page at NPL
A Tribute to Donald Davies (1924–2000)
fro
Living Internet
Computer Networks: The Heralds of Resource Sharing
documentary ca. 1972 about the ARPANET. Includes footage of Donald W. Davies (at 19m20s).
{{DEFAULTSORT:Davies, Donald Watts
1924 births
2000 deaths
Alumni of Imperial College London
Commanders of the Order of the British Empire
Fellows of the British Computer Society
Fellows of the Royal Society
History of computing in the United Kingdom
Internet pioneers
Packets (information technology)
People from Treorchy
Recreational cryptographers
Scientists of the National Physical Laboratory (United Kingdom)
Welsh computer scientists
Welsh inventors