The RUBY_PLATFORM constant is documented in the latest Pickaxe as "The identifier of the platform running this program." Actually it appears to actually be the identifier of the platform on which ruby was compiled. For example, I'm running a darwin ports version of Ruby installed back when this machine was running OS X 10.4 (Tiger), it has since been upgraded to Leopard 10.5.7 $ ruby -e'p RUBY_PLATFORM;p `uname -a`' "i686-darwin8.11.1" "Darwin Macintosh-3.local 9.7.0 Darwin Kernel Version 9.7.0: Tue Mar 31 22:52:17 PDT 2009; root:xnu-1228.12.14~1/RELEASE_I386 i386\n" Note the difference. I just noticed this today when I tried out a new OS X specific gem which baled out when it tought I was running a back-level version of OS X. I'd prefer that that implementation match the documentation, but if the documentation needs to match the implemenation then I guess that should be done. -- Rick DeNatale Blog: http://talklikeaduck.denhaven2.com/ Twitter: http://twitter.com/RickDeNatale WWR: http://www.workingwithrails.com/person/9021-rick-denatale LinkedIn: http://www.linkedin.com/in/rickdenatale