runtime system. The sequential subset of Erlang is a functional language, with strict evaluation, single assignment, and dynamic typing. For concurrency it follows the Actor model. It was designed by Ericsson to support
distributed, fault-tolerant, soft-real-time, non-stop applications. It supports hot swapping so code can be changed without stopping a system. Erlang was originally a proprietary language within Ericsson, but was released as open source in 1998. The Ericsson implementation primarily runs interpreted virtual machine code, but it also includes a native code compiler (not supported on all platforms), developed by the High-Performance Erlang Project (HiPE) at Uppsala University. It also now supports interpretation via escript as of r11b-4.

Creating and managing processes is trivial in Erlang, whereas threads are considered a complicated and error prone topic in most languages. In Erlang, all concurrency is explicit.

Erlang is named after A. K. Erlang. It is sometimes thought that its name is an abbreviation of Ericsson Language, owing to its heavy use inside Ericsson. According to Bjarne Däcker, who headed the Computer Science Lab at the time, this duality is intentional.[http://www.erlang.org/pipermail/erlang-questions/1999-February/000098.html]"