TinyRB: A Young, Tiny Ruby VM for Us to Play With
Marc-André Cournoyer has proven that almost anything is possible by developing a small, functional, and surprisingly "unslow" Ruby VM called TinyRB. Some basic testing shows that it's faster than 1.8 on a Fibonacci benchmark, though slightly slower than JRuby, Rubinius, and YARV (Ruby 1.9).
Coming in at just 1541 lines of code so far, TinyRB is not going to be replacing your usual Ruby interpreter anytime soon. While it supports most of the keywords and some base classes including Class, Object, Fixnum, Symbol, and String, there's no support for Array, Module, Float, and a whole ton of essential stuff.
TinyRB, in its current state, is a playground for you to mess around in. In his last keynote at RubyConf 2008, Dave Thomas suggested we "fork Ruby" in many different ways, and TinyRB enables you to do that on a small scale. So newbies.. move on - but if the thought of experimenting and playing with a Ruby VM is something that gets you putting in a major Red Bull and pizza order.. dive in.
In other fringe implementation news, Brian Ford talks about how some new tweaks have increased Rubinius' performance