XFree86TM is a generally available implementation of X servers for PC UNIX systems. It was developed by a number of programmers who got together in 1992 to form the XFree86-Team. This resulted in the founding in 1994 of a company called the XFree86 Project, Inc. The mission of this company is to make XFree86TM available to as broad an audience as possible and to contribute its research and development effort to the future of X Window.

It doesn't matter whether the X Clients are executed locally, i.e. on the machine at which you are working, or remotely on another system in the network. In the latter case, only the screen output of the program is transferred via the network to the local machine; all processing is carried out on the remote system. This makes it possible in a network, for all application programs to be run on a powerful application server while the client systems can just be simple terminals. This configuration saves not only the high costs of new hardware, but also reduces the administration effort for the network.

Another special feature of the X Window System is its window-management. On a graphical user-interface, all applications are displayed in windows. With X Window, the look (frames, size, colors, buttons, etc.) and feel (e.g. placement and texture) are not controlled by the X server, but by a so-called Window Manager.

What might at first sound confusing soon appears to be a major advantage when you take a closer look: Different Window Managers, allow the user to create the look and feel of his interface himself. It goes without saying under Linux that every Window Manager is in itself freely configurable .

In larger heterogeneous networks, the availability of several Window Managers makes it possible to create a single interface across several hardware architectures. With fvwm95 and qvwm there are even two Window Managers available that have been designed along the lines of the Windows 95 interface.