X server
X server is the abbreviation of Graphical Interface Server in Linux system. The interface of Windows system is an inseparable part of the system, and the display of various window operation interfaces is directly managed by the system core, while the graphical interface of Linux is not a necessary part of the system, it can run under the condition of no interface. When Linux is required to provide an interface, the system will establish one or more X servers, interact with the window manager through the X protocol, and generate interactive interfaces such as windows, status bars, buttons, etc. by applications independent of the system.
The more common Linux interface operating environments are KDE and GNOME, which provide system support for the X server, not the Linux core. Summarize the hierarchical relationship of the linux graphical interface:
linux itself -> X server <-[talk through X protocol] -> window manager (integrated desktop environment) -> X application.