The X Protocol (X or X11) is a display protocol that primarily displays and manages UNIX graphical information. The X Server program handles requests for displaying information and returns user input, such as keyboard or mouse use. This application is performing the computational work of the computer. It makes requests to the server for windows to be drawn, closed, etc. X labels itself as the server and the user as the client. In this course, X protocol is primarily used on Linux machines to access the graphical aspects of the terminal. Windows machines do not natively support X protocol.