About concurrency and the GIL

During RubyConf 2011, concurrency was a really hot topic. This is not a new issue, and the JRuby team has been talking about true concurrency for quite a while . The Global Interpreter Lock has also been in a subject a lot of discussions in the Python community and it’s not surprising that the Ruby community experiences the same debates since the evolution of their implementations are somewhat similar. (There might also be some tension between EngineYard hiring the JRuby and Rubinius teams and Heroku which recently hired Matz (Ruby’s creator) and Nobu, the #1 C Ruby contributor)
The GIL was probably even more of a hot topic now that Rubinius is about the join JRuby and MacRuby in the realm of GIL-less Ruby implementations.

http://merbist.com/2011/10/03/about-concurrency-and-the-gil/
http://rubyconf11.merbist.com/