Donald Watts Davies

British computer scientist who was a co-inventor of packet switching (and originator of the term), along with Paul Baran in the US.

Davies was born in Treorchy, Wales, in 1924. His father died when he was only three years old, leaving his mother to raise him and his twin sister. The family moved to Portsmouth when he was six. He showed exceptional aptitude for mathematics and science from an early age, and went on to earn two first-class degrees from Imperial College London?one in physics in 1943, and one in mathematics in 1947. He also earned a graduate degree from Imperial College in 1948.

Davies joined the National Physical Laboratory (NPL) in 1947, where he worked under Alan Turing on the Automatic Computing Engine (ACE) project. Turing?s influence on Davies was profound, and he later credited Turing with shaping his thinking about computing. Davies was among the small team that built the Pilot ACE, one of the earliest computers to run in the United Kingdom, which first ran in 1950. He continues to work at NPL for the rest of his career, eventually becoming superintendent of the Computer Science division from 1966?1978.

In 1965, Davies independently conceived the idea of breaking data into what he called ?packets? for transmission across a network?a concept he developed without knowledge of Paul Baran?s parallel work in the US. He proposed a national data network based on this concept in 1966. Though the proposal was not adopted at a national level, it directly influenced the development of ARPANET, the precursor to the modern internet. Davies?s team at NPL built a local-area data network using packet-switching principles in 1969, one of the earliest such networks in the world.

Davies retired from NPL in 1984. He then worked as a consultant and continued to contribute to the field of computer security, with a particular focus on cryptography. He co-authors the book ?Security for Computer Networks? in 1984, which becomes a standard reference in the field. He received numerous honors for his contributions, including being appointed a Commander of the Order of the British Empire (CBE) in 1983. Davies died on 28 May 2000, in Esher, Surrey.