ARCHIVED: What is the X Window System?

The X Window System, often known as X, is a windowing system for graphics workstations developed at MIT with support from DEC. It is based on a client/server model: a networked computer or workstation runs an X server, and client programs running on connected workstations request services from the server. The server handles input and output devices and generates the graphical displays used by the clients.

Like many popular graphical user interfaces, the X Window System displays information and applications in rectangular windows arrayed on a desktop-style screen, known as the root window. Windows can be resized, moved, and otherwise manipulated with a mouse. The use of multiple windows lets you perform tasks concurrently in ways that are cumbersome or impossible in text-only displays. For example, in a particular X session, you could have several windows open at the same time containing login sessions to different computers, an editor, a paint program, and a mathematical application, and be able to cut and paste information between the windows.

For more about X, visit the X.Org web page.

X.Org is part of the Open Group and is responsible for managing development of the X Window System.

On many Unix computers, X user applications are in the /usr/bin/X11/ directory, but in Solaris, they are in /usr/openwin/bin, while in most Linux distributions, they are in /usr/bin.

X server programs exist for many platforms, including all modern Unix implementations (e.g., Solaris, Linux, AIX, FreeBSD), as well as Mac OS X and Windows.