X Window System & X11

http://en.wikipedia.org/wiki/X_Window_System

 

The X Window System (commonly X or X11 ) is a computer software system and network protocol that provides a graphical user interface (GUI) for networked computers, and was initially developed as part of Project Athena . It implements the X display protocol and provides windowing on raster graphics (bitmap) computer displays and manages keyboard and pointing device control functions. In its standard distribution, it is a complete, albeit simple, display and human interface solution, but also delivers a standard toolkit and protocol stack for building graphical user interfaces on most Unix-like operating systems and OpenVMS , and has been ported to many other contemporary general purpose operating systems. Desktop environments such as OpenWindows , CDE , GNOME , KDE , and Xfce , use the X Window System.

 

X provides the basic framework, or primitives, for building such GUI environments: drawing and moving windows on the screen and interacting with a mouse and/or keyboard. X does not mandate the user interface — individual client programs handle this. As such, the visual styling of X-based environments varies greatly; different programs may present radically different interfaces. X is built as an additional application layer on top of the operating system kernel .

Unlike previous display protocols, X was specifically designed to be used over network connections rather than on an integral or attached display device. X features network transparency : the machine where an application program (the client application) runs can differ from the user's local machine (the display server ).

 

X originated at MIT in 1984. The current protocol version, X11, appeared in 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 .

 

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