Except for the interfaces running on the Macintosh and the PC in the drop-in center, all the workstations in the BIR run GUI's that are in one form or another derivatives of X11. The server also takes output from the client and updates the appropriate window on the display. Since X is a network based windowing system, clients do not have to be running on the same system as the server . A client may be run on a remote system and have its output redirected to the local server . Terminology windows Rectangular regions on your display in which operations are performed.
Windows often overlap each other.
Overlaping windows do not interfere with the process run in each window. The shaded area that fills the entire screen is called the root or background window. Icons help keep your display uncluttered. In fact the client may continue to run even with the window iconified. A 3 button mouse is the most common pointing device.