Joe Armstrong, who has died aged 68 from complications related to pulmonary fibrosis, was a computer scientist and one of the creators at Ericsson of the programming language Erlang, used by companies as diverse as Bet365, WhatsApp and Cisco.
It was Joe’s idea to write a book on the language – Concurrent Programming in Erlang (co-authored with Michael Williams and Robert Virding, 1992) – rather than just an internal manual for the company, as a precursor to the language being released as open-source in 1998. This ensured the widespread take-up of Erlang essential to its development, in terms both of feedback and of training programmers. Erlang was – and still is – used to build some of the infrastructure equipment for mobile broadband data. In Ericsson it is now mainly used to develop parts of the 4G and 5G mobile networks.
Born in Bournemouth, Joe was the son of Walter Armstrong, a lawyer, and Roma (nee Titmas), who was a comptometer operator during the war. Joe failed the 11-plus exam and went to a secondary modern school before transferring to Bournemouth grammar school for the sixth form. He was interested in programming and software technology from an early age.
He studied theoretical physics at University College London, graduating in 1972, then worked at Edinburgh University as a research assistant in artificial intelligence. A founding member of the British Robotics Association, he wrote papers on robotic vision.
Two years later Joe moved to Kiruna in Sweden to do research on the aurora borealis (the northern lights). From there he went to the Swedish Space Corporation, where he developed the ground station software for the Swedish Viking satellite.
In 1984 Joe was recruited to Ericsson’s computer science laboratory, which I managed. There he showed great initiative and took a leading role in the creation of Erlang.
He worked for a few years at the Swedish Institute of Computer Science (2001-04), receiving his PhD in 2003 for a thesis that dealt with the error-handling mechanism in Erlang, then returned to Ericsson, where he stayed until 2015. He finished his career as an associate professor at the KTH Royal Institute of Technology in Stockholm.
Nobody could avoid being affected by Joe’s good mood and boundless enthusiasm. He was highly appreciated as a speaker at international conferences. Many programmers can testify to just how important Joe has been for them in developing their profession.
Joe had many interests besides his work, not least music, politics, literature and photography.
In 1977 he married Helen Taylor, a translator. She survives him, along with their children, Thomas and Claire.