Erlang, originally created by Ericsson in 1986, is a functional programming language which was released as open source around 10 years ago and flourished ever since. In this Q&A, Erlang creator Joe Armstrong talks about its beginnings as a control program for a telephone exchange, its flexibility and its modern day usage in open source programs. “In the Erlang world we have over twenty years of experience with designing and implementing parallel algorithms. What we loose in sequential processing speed we win back in parallel performance and fault-tolerance,” Armstrong said. He also mentions how multi-core processors pushed the development of Erlang and the advantages of hot swapping.