X Window System
Wikipedia Reference Information
In computing, the X Window System(commonly X11 or X) is a networking and display protocol which provides windowing on bitmap displays. It provides the standard toolkit and protocol to build graphical user interfaces (GUIs) on Unix, Unix-like operating systems, and OpenVMS, and is supported by almost all other modern operating systems.
X provides the basic framework, or primitives, for building 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 features network transparency: the machine where application programs (the client applications) run 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, version 11 release 7.2, available as free software under the MIT License and similar permissive licenses . Version 7.2 was originally planned to be released on November 24, 2006, later pushed back until December 11, 2006, and not actually released until February 15, 2007.
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