X11

The X Window System, more simply 'X' or 'X11', is judged worldwide to be one of the most successful open source, collaborative technologies developed to date. It is the de facto standard graphical engine for the Unix and Linux operating systems.

• http://www.x.org/X11.html

• http://www.x.org/X11_protocol.html

• http://www.xfree86.org/