Linux

http://en.wikipedia.org/wiki/Linux
Tux the penguin, mascot of Linux[1]
Developer Community
Written in Primarily C and assembly
OS family Unix-like
Working state Current
Source model Mainly open source, closed source also available
Initial release 1991; 24 years ago
Marketing target Personal computers, mobile devices, embedded devices, servers, mainframes, supercomputers
Available in Multilingual
Platforms Alpha, ARC, ARM, AVR32, Blackfin, C6x, ETRAX CRIS, FR-V, H8/300, Hexagon, Itanium, M32R, m68k, META, Microblaze, MIPS, MN103, Nios II, OpenRISC, PA-RISC, PowerPC, s390, S+core, SuperH, SPARC, TILE64, Unicore32, x86, Xtensa
Kernel type Monolithic (Linux kernel)
Userland Various
Default user interface Many
License GPL version¬†2[2] and other free and open-source licenses, except for the “Linux” trademark[a]