X ( [#!IB-H915012!#], [#!IB-B911403!#], [#!IB-H925537!#] ) is a windowing system built for UNIX but is intended to be machine and operating system independent. X is built on the client/server model. The server side of X resides on the desktop computer and controls the monitor, keyboard, and mouse. The client side of X may reside anywhere on the network. These X clients are called X-applications. A protocol, the X protocol, is used to communicate between X client and X servers.
X is a windowing system and not a user interface paradigm. Motif is the most common accepted user interface paradigm specifying sliders, buttons, basic design of windows, and other widgets.
X was created in the 1980s at MIT. The team was very small lead by Jim Gettys. X is well documented and the source code is free and readily available.
There were two decisions which hampered the wide acceptance of X. The first decision was not to dictate a common look-and-feel. This lead to many different windowing paradigms. Many times competition leads to better answers, but in this case, competition lead to conflicts and interoperability between systems. Eventually, the standards committee for X picked Motif.
The second decision was to break the inode paradigm of UNIX. This meant that X could not be scripted. One application could no longer run another application in a piped manor. Attempts to fix this problem are underway in the TCL scripting language.
See tables 7.17 and 7.18 starting on page .