Why is X Appropriate

The X-Windows system is essentially divided in two parts. Client programs and the Display server. These communicate by a well defined protocol, which allows the client program and the Display server to be on separate machines. There is an access control mechanism to prevent a client program arbitrarily accessing the display server on another machine without first being given permission. The server allows a program to create and manage a number of windows on a display/machine. A Client program can be a window manager, which keeps track of a set of other applications. Any X Application can notify other applications of events which it has asked the X Server to notify it with.