Debian is a Linux operating system initiated in 1993 by Ian Murdock. There are three main versions: Old Stable, Stable, and Experimental. A new Stable version is released every two years with three years of official support. Debian has influenced over 136 Linux distributions. It includes desktop environments like GNOME, KDE, XFCE, LXDE, MATE, and Cinnamon. Debian can be used for purposes like notebooks, desktops, workstations, servers, and more. It offers both text-based and graphical installers.