Joseph Leslie Armstrong (27 December 1950 – 20 April 2019) was a computer scientist working in the area of fault-tolerant distributed systems.

[2] After briefly working for Donald Michie at the University of Edinburgh, Armstrong moved to Sweden in 1974 and joined the Ericsson Computer Science Laboratory at Kista in 1984.

[2] Peter Seibel wrote: Originally a physicist, he switched to computer science when he ran out of money in the middle of his physics PhD and landed a job as a researcher working for Donald Michie — one of the founders of the field of artificial intelligence in Britain.

When funding for AI dried up as a result of the famous Lighthill report, it was back to physics-related programming for more than half a decade, first at the EISCAT scientific association and later the Swedish Space Corporation, before finally joining the Ericsson Computer Science Lab where he invented Erlang.

[5]It was at Ericsson in 1986, that he worked with Robert Virding and Mike Williams, to invent the Erlang programming language,[2] which was released as open source in 1998.