Linux
A free and open-source operating system developed by
Linus Torvalds and friends and was first
announced by Linus in a post he made August 25, 1991. The Linux kernel runs on numerous different platforms including the Intel and Alpha platform and is available under the GNU General Public License.
Also see: DSL, FREAX, Gentoo, Operating system definitions, Puppy Linux, Tux, Unix, Variant