Debian is a computer operating system composed entirely of free and open source software. The primary form, Debian GNU/Linux, is a popular and influential Linux distribution. An operating system is the set of basic programs and utilities that make your computer run. Debian uses the Linux kernel (the core of an operating system), but most of the basic OS tools come from the GNU project; hence the name GNU/Linux. (Source www.debian.org) . Debian is known for strict adherence to the Unix and free software philosophies as well as using open development and testing processes. Debian can be used as a desktop as well as server operating system.