The X window system (commonly X Window System or X11, based on its current major version being 11) is a computer software system and network protocol that provides a basis for graphical user interfaces (GUI) for networked computers.
X11 is the most common windowing system for Unix & Linux computers. The developer of the X11 system is X.org. At a high level, an X11 “server” runs on one system, and an X11 “client” connects to the server, either locally over sockets, or over the network. These X11 clients are often graphical applications (e.g. xeyes, xclock) or graphical interfaces to a terminal (e.g. xterm). Some related software includes:
- vnc - Virtual Network Computing - a cross-platform graphical desktop sharing system that transmits keyboard & mouse events as well as screen updates from a “server” side to one or more “clients”. Related to this is Xvnc, a process that acts as either an X11 server or a VNC server.
- RDP - Remote Desktop Protocol; originated in Windows and was later ported to Unix