Donald Watts Davies was a Welsh computer scientist who co-developed the idea of a communications system based on packet-switching. Born in Treorchy, Rhondda Valley, Wales, in 1924, Davies studied at Imperial College London in the 1940's, and would eventually spend most of his career conducting research at the UK's National Physical Laboratory. When Davies first began working at National Physical Laboratory, he worked alongside the pioneer of computer science, Alan Turing. It's reputed that Davies highlighted some errors within Turing's theoretical programming, much to the chagrin of the aforementioned computer scientist. Turing, at that time, was working on a project to develop a automatic computing engine. Ambitious in the scope, it failed to meet expectation, which led to Turing's exit. Davies took over the project, limited it's ambitions and delivered a working ACE computer by the early 1950's. Davies became interested in researching communication between computers in the 1960's. While visiting MIT in the US, Davies noticed a problem in their time-share computing network, and came back to the UK to develop an improved system.
In the mid 1960's, Donald Davies collaborated with Roger Scantlebury, and published a number of important papers and reports related to packet switching. In 1965, it has been claimed that Davies attended a IFIP meeting in New York, and a NPL meeting in the UK, where he discussed network communications with Lawrence Roberts (who built ARPANET) and discussed time-sharing research with MIT scientists. By the end of 1965, Davies published two papers: "Remote Online Data Processing and its Communication Needs" and "Proposal for the Development of a National Communications Service for Online Data Processing". In 1966, Davies would hold a lecture, outlining his ideas, with telecommunication manufacturers and this would lead to a paper titled "A Digital Communications Network For Computers" being published. Davies' paper would coin the term "packet" and "packet switching"; later American computer networks would adopt this term. Scantlebury believed that this paper outlined a network that was more advanced than any proposed in the United States.
By the end of the 1967, Davies and Scantlebury produced a written proposal for a NPL Network. This network would be referred to as the: National Physical Laboratory Network, NPL Data Communications Network, NPL Data Network or NPL Network. The first operational version of the network was launched in 1969 and was named Mark I. Mark I was replaced by the Mark II network in 1973. Neither network received the same level of funding as the American ARPANET network. The Mark II network was decommissioned in 1986. Mark I and ARPANET were operational in 1969, but Mark I was launched before ARPANET, so Mark I was the first packet switching network, and initially operated at a higher line speed than ARPANET (768 kbps compared to 50 kbps).
Donald Davies died on the 28th of May 2000. His contribution to computer communication networks has been recognised with a number of awards: blue plaque (Treorchy, Wales) (permanent historical marker) in the UK; member of the Internet Hall of Fame (Pioneer: 2012); and British Computer Society Award (1974).