If you install macports you can install gcc select, and then choose your gcc version.
/opt/local/bin/port install gcc_select
To see your versions use
port select --list gcc
To select a version use
sudo port select --set gcc gcc40
R is a language and environment for statistical computing and graphics. It is a GNU project which is similar to the S language and environment which was developed at Bell Laboratories by John Chambers and colleagues. R can be considered as a different implementation of S.
VirtualBox is a general-purpose full virtualizer for x86 hardware. Targeted at server, desktop and embedded use, it is now the only professional-quality virtualization solution that is also Open Source Software. run bsd on a mac.
Despite begin a unique, key marketing feature of Snow Leopard, Apple has decided to open the code behind Grand Central Dispatch under the liberal Apache 2.0 license. Snow Leopard's new Grand Central Dispatch feature, which serves as a system-wide mechanism for managing parallel task execution across multiple processor cores for developers, involves multiple components in the operating system.