X11 is an extensible windowing system for bitmap displays. It forms the foundation of most Unix operating system GUIs.
The X Window System (commonly known as X11, based on its current major version being 11, or shortened to simply X, and sometimes informally X-Windows) is a computer software system and network protocol that provides a basis for graphical user interfaces (GUIs) and rich input device capability for networked computers. It creates a hardware abstraction layer where software is written to use a generalized set of commands, allowing for device independence and reuse of programs on any computer that implements X.
History
X originated at the Massachusetts Institute of Technology (MIT) in 1984. The protocol version has been X11 since September 1987. The X.Org Foundation leads the X project, with the current reference implementation, X.Org Server, available as free and open source software under the MIT License and similar permissive licenses.
The key design principles of X11 are
- define methods, not policies
- extensibility
- network transparency
- window based
A X11 system consists of
a X11 Server that connects with one or more display devices (called Screens), user input devices and accepts connections from so called…
X11 Clients which communicate with the X11 server to receive user input and draw graphics (into windows) through it.