X Window System
The X Window system, or X, or X11:
- Manages some hardware:
- graphics/video cards,
- keyboard and mouse.
X enables text copy&paste with the mouse: select text using the left button, and copy it elsewhere with the middle button.
- Manages the display of applications in windows.
Client Server system: a X server on a machine can display a client application running on another machine.
An application server can run a client application for many machines with an X server (e.g. OpenOffice.org).
- X Window System - http://en.wikipedia.org/wiki/XWindow