# x11

x11 (also known as the X Window System) is a display protocol and windowing system that provides the graphical interface layer for Unix-like operating systems, including Linux. It’s been the foundation of Linux GUIs for decades, though it’
s now being gradually replaced by Wayland.

🧩 Core Concepts of X11

- Client–Server Architecture:
  - The X server handles input/output devices (keyboard, mouse, display).
  - X clients are applications that request graphical output and user input.
- Network Transparency:
  - X11 allows applications to run on one machine and display on another over a network — a key feature for remote GUI sessions.
- Protocol Version:
  - The current version is X11, released in 1987.
  - That’s why it’s often called “X11” even though the system itself is just “X.”
- Modularity:
  - X11 doesn’t dictate window decorations or behavior — that’s handled by window managers like KWin, i3, or Openbox.
  - It also doesn’t include a desktop environment — DEs like GNOME or KDE build on top of X11.