XCAS
XCAS or on-call close air support (CAS) is a technique of air warfare which first achieved recognition in Operation Enduring Freedom, the US-led invasion of Afghanistan in 2001. It is associated with new developments in US Air Force doctrine emphasizing the centrality of effects-based targetting.
Giac/Xcas is a free computer algebra system for Windows, Mac OS X and Linux/Unix. It has a compatibility mode for maple, mupad and the TI89. Xcas is one of the various interfaces of Giac, a free (GPL) C++ library for computer algebra.