Donald Watts Davies, CBE, FRS (7 June 1924 – 28 May 2000) was a Welsh computer scientist who was employed at the UK National Physical Laboratory (NPL). In 1965 he developed the concept of packet switching, which is today the dominant basis for data communications in computer networks worldwide, and implemented it in the NPL network. This was independent of the work of Paul Baran in the United States who had a similar idea in the early 1960s. The ARPANET project, a precursor to the Internet, credited Davies for his influence.
Donald Watts Davies
|Born||7 June 1924|
|Died||28 May 2000 (aged 75)|
|Alma mater||Imperial College|
|Known for||Packet switching|
|Institutions||National Physical Laboratory|
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. 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 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.
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 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 the project over and concentrated on delivering the less ambitious Pilot ACE computer, which first worked in May 1950. A commercial spin-off, DEUCE 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.
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. Unbeknown to him, Paul Baran of the RAND Corporation in the United States was also working on a similar concept who, when he became aware of Davies's work acknowledged that they both had equally discovered the concept.
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 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", today known as a router.
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 a conference in Gatlinburg, Tennessee, 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.
Davies first presented his own ideas on packet switching at a conference in Edinburgh on 5 August 1968. At NPL Davies helped build a packet-switched network (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.
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
You and I share a common view of what packet switching is all about, since you and I independently came up with the same ingredients.
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 some, including Robert Taylor, Baran and Davies. The U.S. National Inventors Hall of Fame, which recognizes inventors who hold a U.S. patent of highly significant technology, records Donald Davies and Paul Baran as the inventors of digital packet switching.
Davies relinquished his management responsibilities in 1979 to return to research. He became particularly interested in computer network security. He retired from the NPL in 1984, becoming a leading consultant on data security to the banking industry. Together with David O. Clayden, they designed the Message Authenticator Algorithm (MAA), an early Message Authentication Code that was adopted as international standard ISO 8731-2 in 1987. In 1987, he became a visiting professor at Royal Holloway and Bedford New College.
Davies was appointed a Distinguished Fellow of the British Computer Society in 1975, a CBE in 1983 and a Fellow of the Royal Society in 1987. In 2007, Davies was inducted into the National Inventors Hall of Fame, and in 2012 he was inducted into the Internet Hall of Fame by the Internet Society. A blue plaque commemorating Davies was unveiled in Treorchy in July 2013.
Davies was survived by his wife Diane, a daughter and two sons.
Then in June 1966, Davies wrote a second internal paper, "Proposal for a Digital Communication Network" In which he coined the word packet,- a small sub part of the message the user wants to send, and also introduced the concept of an "Interface computer" to sit between the user equipment and the packet network.
This led to an outcry among many of the other Internet pioneers, who publicly attacked Kleinrock and said that his brief mention of breaking messages into smaller pieces did not come close to being a proposal for packet switching
Authors who have interviewed dozens of Arpanet pioneers know very well that the Kleinrock-Roberts claims are not believed.
The Internet is really the work of a thousand people," Mr. Baran said. "And of all the stories about what different people have done, all the pieces fit together. It's just this one little case that seems to be an aberration.
I can find no evidence that he understood the principles of packet switching.
The Advanced Research Projects Agency Network (ARPANET) was an early packet-switching network and the first network to implement the TCP/IP protocol suite. Both technologies became the technical foundation of the Internet. The ARPANET was initially founded by the Advanced Research Projects Agency (ARPA) of the United States Department of Defense.The packet-switching methodology employed in the ARPANET was based on concepts and designs by Leonard Kleinrock, Paul Baran, Donald Davies, and Lawrence Roberts. The TCP/IP communications protocols were developed for the ARPANET by computer scientists Robert Kahn and Vint Cerf, and incorporated concepts from the French CYCLADES project directed by Louis Pouzin.
As the project progressed, protocols for internetworking were developed by which multiple separate networks could be joined into a network of networks. Access to the ARPANET was expanded in 1981, when the National Science Foundation (NSF) funded the Computer Science Network (CSNET). In 1982, the Internet protocol suite (TCP/IP) was introduced as the standard networking protocol on the ARPANET. In the early 1980s the NSF funded the establishment of national supercomputing centers at several universities and provided interconnectivity in 1986 with the NSFNET project, which also created network access to the supercomputer sites in the United States from research and education organizations. The ARPANET was decommissioned in 1989.Bartonville Agreement
The Bartonville Agreement came from a meeting held on May 1999 by bishops representing both the Anglican Communion's American province (The Episcopal Church) and a number of Continuing Anglican jurisdictions in North America. As such, it was an early effort made by conservative Episcopal bishops and Continuing Anglican bishops to voice a common set of principles which might become the basis of future cooperation between their churches or dioceses. The schism that had divided these church bodies had occurred in 1977 at the Congress of St. Louis when "Continuers" met and formed a new Anglican church in reaction to changes in doctrine and practice that had been approved by The Episcopal Church and the Anglican Church of Canada.
These bishops assembled in Bartonville, Illinois at Saint Benedict's Abbey. In his opening comments the host, Abbot Alberto Morales, encouraged those present "to let the Holy Spirit guide us and show us the way that we should go...that as we face the new millennium we may present to the world a portion of the Anglican Communion reconciled and united, which in turn, may be an example to imitate for all good and faithful Anglicans and for the Church in general." The result of the meeting was the signing of a "Call to prayer" for unity and a determination to meet again.
A second convocation of bishops took place in Bartonville on October 29 of the same year. The result of this meeting was the signing of the Articles of Ecclesiastical Fellowship.
The signatories of the original compact were the following:
Keith Ackerman, Episcopal Diocese of Quincy
Robert Crawley, Anglican Catholic Church of Canada
A. Donald Davies, Episcopal Missionary Church Primate *
Louis Falk, Anglican Church in America Primate
Herbert Groce, Anglican Rite Synod in America
Walter Grundorf, Anglican Province of America Primate
John Hepworth, Anglican Catholic Church of Australia
Jack Leo Iker, Episcopal Diocese of Fort Worth
Joel Johnson, Anglican Rite Synod in the Americas
Edward MacBurney, retired Episcopal bishop of Quincy
Scott Earle McLaughlin, Orthodox Anglican Church
Robert Mercer, Anglican Catholic Church of Canada Primate
Donald Parsons, retired Episcopal bishop of Quincy
Donald Perschall, American Anglican Church/Anglican Synod Primate
Larry Shaver, Diocese of St. Augustine, Anglican Rite Synod in America* It is reported that Davies was present but did not sign the document.Present but not empowered to sign was:
Joseph Deyman, Diocese of the Midwest, Anglican Catholic Church
Royal U. Grote, Jr. Diocese of Mid-America, Presiding Bishop of the Reformed Episcopal ChurchThe following were signatories of the Articles of Ecclesiastical Fellowship:
Louis Falk, ACA Primate
Herbert Groce, ARSA Primate
Walter Grundorf, APA Primate
Scott Earle McLaughlin, OAC
Donald Perschall, AAC & AS Primate
Larry Shaver ARSA
Richard Boyce, Diocese of the West, Anglican Province of America
Ronald Johnson, Philippine Independent Catholic Church
Robert J. Godfrey, Orthodox Anglican ChurchChristian Episcopal Church
The Christian Episcopal Church (XnEC) is a Continuing Anglican jurisdiction consisting of parishes in Canada and the United States and with oversight of several parishes in the Cayman Islands. Its bishops are in apostolic succession through the Right Rev. A. Donald Davies (Deceased). Davies was formerly the Bishop-in-charge of the Convocation of American Churches in Europe and the bishop of the Episcopal Diocese of Fort Worth, Texas.
Bishop Archibald Donald Davies had, in 1970, been consecrated the fourth bishop of the Episcopal Diocese of Dallas. Fifteen bishops of the Episcopal Church assisted at the consecration of Bishop Davies, with John Elbridge Hines as one of the principal consecrators. Bishop Hines had himself been consecrated the fifth bishop of the Episcopal Diocese of Texas in 1945, and was later elected the Presiding Bishop of the Episcopal Church in the United States of America.
In 1992, following years of controversy in the Episcopal Church in the USA and the Anglican Church of Canada over what conservative members considered a steady drift towards both political and religious liberalism, the Episcopal Missionary Church (EMC) was founded. Although this was fifteen years after the Congress of St. Louis at which Anglicans from the USA and Canada created the Continuing Anglican Movement in opposition to women's ordination, Prayer Book alterations, and more relaxed sexual standards approved in ECUSA, the EMC is usually considered a Continuing Church. Bishop Davies was elected its first presiding bishop. He was also elected Archbishop and Primate of the several parishes constituting the Christian Episcopal Church of Canada.
A decade later, a split in the Episcopal Missionary Church's Diocese of the West produced the Christian Episcopal Church in the USA. Those who left the Diocese then appealed to Bishop Davies and joined with the churches in Canada. At one time, the XnEC in the United States counted parishes in Mississippi, South Carolina, California, Arizona, Texas and other states, but at present its parishes are two in Washington State and one in Florida. The current Archbishop and Primate is the Most Reverend Theodore C. Casimes. XnEC's Bishop Co-Adjutor is the Rt. Rev. Dr. Tim Klerekoper.
Every bishop in the Christian Episcopal Church has had Archbishop Davies as one of his consecrators. All, therefore, can claim to have received valid episcopal orders through the bishops of the Church of England, and the Scottish Episcopal Church, but also from the Episcopal Church in the USA.
The Christian Episcopal Church of Canada is headed by The Right Reverend Robert David Redmile.
In September 2017 it was announced by Archbishop Theodore Casimes that Gavin Ashenden had been consecrated as a missionary bishop in the United Kingdom and Europe by the Christian Episcopal Church.Davies attack
In cryptography, the Davies attack is a dedicated statistical cryptanalysis method for attacking the Data Encryption Standard (DES). The attack was originally created in 1987 by Donald Davies. In 1994, Eli Biham and Alex Biryukov made significant improvements to the technique. It is a known-plaintext attack based on the non-uniform distribution of the outputs of pairs of adjacent S-boxes. It works by collecting many known plaintext/ciphertext pairs and calculating the empirical distribution of certain characteristics. Bits of the key can be deduced given sufficiently many known plaintexts, leaving the remaining bits to be found through brute force. There are tradeoffs between the number of required plaintexts, the number of key bits found, and the probability of success; the attack can find 24 bits of the key with 252 known plaintexts and 53% success rate.
The Davies attack can be adapted to other Feistel ciphers besides DES. In 1998, Pornin developed techniques for analyzing and maximizing a cipher's resistance to this kind of cryptanalysis.Donald Davies (bishop)
Archibald Donald Davies (April 15, 1920 – October 16, 2011) was an American Anglican bishop. He was the fourth Episcopal bishop of Dallas and subsequently the first Episcopal bishop of Fort Worth. Davies was a founder of the Evangelical and Catholic Mission. He later founded the Episcopal Missionary Church, after which he became Archbishop and Primate of the Christian Episcopal Church (XnEC).Donald Davies (disambiguation)
Donald Davies (1924–2000) was a Welsh computer scientist.
Donald Davies may also refer to:
Donald Davies (bishop) (1920–2011), American Episcopal bishop
Donnie Davies, 2007 fictional American anti-homosexual campaignerDonny Davies
Harry Donald Davies (13 March 1892 – 6 February 1958) was an English first-class cricketer, amateur footballer and journalist. He was killed in the Munich air disaster. He was an uncle to historian Norman Davies.End-to-end principle
The end-to-end principle is a design framework in computer networking. In networks designed according to this principle, application-specific features reside in the communicating end nodes of the network, rather than in intermediary nodes, such as gateways and routers, that exist to establish the network.
The essence of what would later be called the end-to-end principle was contained in the work of Paul Baran and Donald Davies on packet-switched networks in the 1960s. Louis Pouzin pioneered the use of the end-to-end strategy in the CYCLADES network in the 1970s. The principle was first articulated explicitly in 1981 by Saltzer, Reed, and Clark. The meaning of the end-to-end principle has been continuously reinterpreted ever since its initial articulation. Also, noteworthy formulations of the end-to-end principle can be found before the seminal 1981 Saltzer, Reed, and Clark paper.A basic premise of the principle is that the payoffs from adding features to a simple network quickly diminish, especially in cases in which the end hosts have to implement those functions only for reasons of conformance, i.e. completeness and correctness based on a specification. Implementing a specific function incurs some resource penalties regardless of whether the function is used or not, and implementing a specific function in the network distributes these penalties among all clients.
The end-to-end principle is closely related, and sometimes seen as a direct precursor, to the principle of net neutrality.Episcopal Missionary Church
The Episcopal Missionary Church (EMC) is a Continuing Anglican church body in the United States and a member of the Federation of Anglican Churches in the Americas. Its founding in the early 1990s can be traced to the protests of members of The Episcopal Church who were concerned that their church had become massively influenced by secular humanism (i.e., liberal theologies). At first, these clergy and laymen sought to change the direction of their church by working from within it, to which end they formed a voluntary association, the Episcopal Synod of America.
When they later concluded that this approach would not succeed, a new missionary diocese was formed by them, still attempting to remain within ECUSA. In 1992, however, the missionary diocese withdrew from ECUSA and formed a separate church, the Episcopal Missionary Church. A. Donald Davies, retired ECUSA Bishop of Dallas and Fort Worth, was named the first Presiding Bishop of the Episcopal Missionary Church.
The Episcopal Missionary Church affirms the Holy Scriptures as containing all things necessary to salvation and as the ultimate rule and standard of faith. The church acknowledges the Nicene and Apostles' Creeds and the necessity of the Sacraments of Baptism and Holy Communion. It uses the 1928 American edition of the Book of Common Prayer or the Anglican Missal based upon it, and emphasizes the preservation of apostolic succession. The Episcopal Missionary Church embraces a variety of liturgical styles from low church to high church, evangelical to Anglo-Catholic.
The name Episcopal "Missionary" Church was selected as part of the church's desire to provide a home for all Episcopalians and other Christians who feel that they have been forced from their churches by the growth of liberalism within them. At present, the Episcopal Missionary Church has approximately thirty small parishes scattered throughout the United States.Harry Davies
Harry Davies may refer to:
Harry Davies (footballer, born in Chorley) (fl. 1922–1923), English footballer for Chorley, Port Vale and Bacup Borough
Harry Davies (footballer, born 1876) (1876–?), English footballer for Doncaster Rovers, Gainsborough Trinity, Hull City and Wolverhampton Wanderers
Harry Davies (footballer, born 1888) (1888–1958), English footballer for Stoke
Harry Davies (footballer, born 1904) (1904–1975), English footballer for Huddersfield Town, Port Vale and Stoke City
Harry Davies (rugby union) (born 1994), Welsh rugby player
Harry Davies (politician) (1878–1957), Southern Rhodesian politician
Donny Davies (Harry Donald Davies, 1892–1958), English cricketer, amateur footballer and journalist
Harry Davies (socialist) (1888–1927), Welsh socialist politician and trade unionistHarry Davies (footballer, born 1888)
Harold Donald Davies (1888 – 1958) was an English footballer who played for Stoke.History of the Internet
The history of the Internet begins with the development of electronic computers in the 1950s. Initial concepts of wide area networking originated in several computer science laboratories in the United States, United Kingdom, and France. The U.S. Department of Defense awarded contracts as early as the 1960s, including for the development of the ARPANET project, directed by Robert Taylor and managed by Lawrence Roberts. The first message was sent over the ARPANET in 1969 from computer science Professor Leonard Kleinrock's laboratory at University of California, Los Angeles (UCLA) to the second network node at Stanford Research Institute (SRI).
Packet switching networks such as the NPL network, ARPANET, Merit Network, CYCLADES, and Telenet, were developed in the late 1960s and early 1970s using a variety of communications protocols. Donald Davies first demonstrated packet switching in 1967 at the National Physics Laboratory (NPL) in the UK, which became a testbed for UK research for almost two decades. The ARPANET project led to the development of protocols for internetworking, in which multiple separate networks could be joined into a network of networks.
The Internet protocol suite (TCP/IP) was developed by Robert E. Kahn and Vint Cerf in the 1970s and became the standard networking protocol on the ARPANET, incorporating concepts from the French CYCLADES project directed by Louis Pouzin. In the early 1980s the NSF funded the establishment for national supercomputing centers at several universities, and provided interconnectivity in 1986 with the NSFNET project, which also created network access to the supercomputer sites in the United States from research and education organizations. Commercial Internet service providers (ISPs) began to emerge in the very late 1980s. The ARPANET was decommissioned in 1990. Limited private connections to parts of the Internet by officially commercial entities emerged in several American cities by late 1989 and 1990, and the NSFNET was decommissioned in 1995, removing the last restrictions on the use of the Internet to carry commercial traffic.
In the 1980s, research at CERN in Switzerland by British computer scientist Tim Berners-Lee resulted in the World Wide Web, linking hypertext documents into an information system, accessible from any node on the network. Since the mid-1990s, the Internet has had a revolutionary impact on culture, commerce, and technology, including the rise of near-instant communication by electronic mail, instant messaging, voice over Internet Protocol (VoIP) telephone calls, two-way interactive video calls, and the World Wide Web with its discussion forums, blogs, social networking, and online shopping sites. The research and education community continues to develop and use advanced networks such as JANET in the United Kingdom and Internet2 in the United States. Increasing amounts of data are transmitted at higher and higher speeds over fiber optic networks operating at 1 Gbit/s, 10 Gbit/s, or more. The Internet's takeover of the global communication landscape was almost instant in historical terms: it only communicated 1% of the information flowing through two-way telecommunications networks in the year 1993, already 51% by 2000, and more than 97% of the telecommunicated information by 2007. Today the Internet continues to grow, driven by ever greater amounts of online information, commerce, entertainment, and social networking. However, the future of the global internet may be shaped by regional differences in the world.Lawrence Roberts (scientist)
Lawrence Gilman Roberts (December 21, 1937 – December 26, 2018) was an American engineer who received the Draper Prize in 2001 "for the development of the Internet", and the Principe de Asturias Award in 2002.
As a program manager and office director at the Advanced Research Projects Agency, Roberts and his team created the ARPANET using packet switching techniques invented by British computer scientist Donald Davies and American Paul Baran underpinned by the theoretical work of Leonard Kleinrock. The ARPANET, which was built by the Massachusetts-based company Bolt Beranek and Newman (BBN), was a predecessor to the modern Internet. He later served as CEO of the commercial packet-switching network Telnet.NPL network
The NPL Network or NPL Data Communications Network was a local area computer network operated by a team from the National Physical Laboratory in England that pioneered the concept of packet switching. Following a pilot experiment during 1967, elements of the first version of the network, Mark I, became operational during 1969 then fully operational in 1970, and the Mark II version operated from 1973 until 1986. The NPL network, followed by the wide area ARPANET in the United States, were the first two computer networks that implemented packet switching, and were interconnected in the early 1970s. The NPL network was designed and directed by Donald Davies.National Physical Laboratory (United Kingdom)
The National Physical Laboratory (NPL) is the national measurement standards laboratory for the United Kingdom, based at Bushy Park in Teddington, London, England. It comes under the management of the Department for Business, Energy and Industrial Strategy.Packet switching
Packet switching is a method of grouping data that is transmitted over a digital network into packets. Packets are made of a header and a payload. Data in the header are used by networking hardware to direct the packet to its destination where the payload is extracted and used by application software. Packet switching is the primary basis for data communications in computer networks worldwide.
In the early 1960s, American computer scientist Paul Baran developed the concept Distributed Adaptive Message Block Switching with the goal to provide a fault-tolerant, efficient routing method for telecommunication messages as part of a research program at the RAND Corporation, funded by the US Department of Defense. This concept contrasted and contradicted then-established principles of pre-allocation of network bandwidth, largely fortified by the development of telecommunications in the Bell System. The new concept found little resonance among network implementers until the independent work of British computer scientist Donald Davies at the National Physical Laboratory (United Kingdom) in 1965. Davies is credited with coining the modern term packet switching and inspiring numerous packet switching networks in the decade following, including the incorporation of the concept in the early ARPANET in the United States.Paul Baran
Paul Baran (; April 29, 1926 – March 26, 2011) was a Polish-born Jewish American engineer who was a pioneer in the development of computer networks. He was one of the two independent inventors of packet switching, which is today the dominant basis for data communications in computer networks worldwide, and went on to start several companies and develop other technologies that are an essential part of modern digital communication.Robert David Redmile
Robert David Redmile (born 11 February 1961) is the second Bishop of Richmond of the Christian Episcopal Church of Canada, having succeeded the Primate, and first Bishop of Richmond, Donald Davies, as the second bishop of the diocese, in 2004.Sean Murphy (cryptographer)
Sean Murphy is a cryptographer, currently a professor at Royal Holloway, University of London. He worked on the NESSIE and ECRYPT projects. His notable research includes the cryptanalysis of FEAL and the Advanced Encryption Standard, and the use of stochastic and statistical techniques in cryptology. With Donald Davies he also developed Davies' attack on DES.
Murphy received his Ph.D. in mathematics in 1989 from the University of Bath.