Just watched Erlang the Movie from 1990 (200M, via lambda-the-ultimate). Such a laugh I had to watch again :-). However, there was a serious demonstration of a “hot software upgrade” technology which allowed the system software to be patched while continuing uninterrupted in “24×7” style.
Erlang is a programming language that uses message passing concurrency rather than shared state concurrency (as in Java). Some other languages with message passing concurrency are Oz, E, Io and apparently MultiLisp (a Scheme dialect).