| From Joe Armstrong's thesis (p. 6): > In February 1998 Erlang was banned for new product development within Ericsson—the main reason for the ban was that Ericsson wanted to be a consumer of sodware technologies rather than a producer. From Bjarne Däcker's thesis (2000, p. 37): > In February 1998, Erlang was banned within Ericsson Radio AB (ERA) for new product projects aimed for external customers because:
>
> “The selection of an implementation language implies a more long-term commitment than selection of processors and OS, due to the longer life cycle of implemented products. Use of a proprietary language, implies a continued effort to maintain and further develop the support and the development environment. It further implies that we cannot easily benefit from, and find synergy with, the evolution following the large scale deployment of globally used languages.” [Ri98] |
"In February 1998, Ericsson Radio Systems banned the in-house use of Erlang for new products, citing a preference for non-proprietary languages. The ban caused Armstrong and others to make plans to leave Ericsson. In March 1998 Ericsson announced the AXD301 switch, containing over a million lines of Erlang and reported to achieve a high availability of nine "9"s. In December 1998, the implementation of Erlang was open-sourced and most of the Erlang team resigned to form a new company Bluetail AB. Ericsson eventually relaxed the ban and re-hired Armstrong in 2004."
Not wanting to rely on a fairly esoteric in-house language makes some sense.
Since then things have changed significantly of course.