The X-Window is a graphical user interface and is primarily used for display on Unix operating systems.
It is a platform-independent client-server protocol, which is therefore not tied to any specific hardware or operating system.
It enables a graphical Windows interface to be managed and used across a wide network.
On the one hand, it forms the basis of the graphical user interface on Unix systems, but it can also be used on other platforms.
With the client-server protocol, different layers form the communication points of the client, through which it can reach the server. This includes the X Server, X Protocol, Xlib, X Toolkit and X Client.
The clients are formed by X applications and the server by the X window terminal.
For this reason, the client is also responsible for running the application and the server for processing, display and input and output.