Desktop Environment

Desktop Environment is not a must for Linux, e.g. Ubuntu Server edition ships without a desktop. Desktop is just another software running in Linux, and it can be swapped.

GNOME vs KDE vs Others

The most popular Linux desktop environments: GNOME and KDE.

• KDE: Based on the QT GUI widget toolkit. QT was not GPL compatible until version 3.0.
• GNOME: Based on GTK+ (Gimp ToolKit) GUI widget toolkit. GTK+ (GUI toolkit) was created to build GIMP in 1997. GNOME was founded partly because QT was not GPL compatible.
• Others
  • Cinnamon
  • XFCE is lightweight, good for remote desk.

E.g. Ubuntu uses GNOME by default, but has several other flavors with different desktop environments: Kubuntu uses KDE, Xubuntu uses XFCE, etc.

X11 vs X.org vs XDG vs FreeDesktop.org

• X11, a.k.a. X Window System, provides a basic framework for GUI. X protocol had been version 11 since 1987, thus X11.
• X.org is a popular open source implementation of X11.
• XDG stands for X Development Group, the old name of FreeDesktop.org.
• FreeDesktop.org is part of X.org Foundation.

Wayland

• Wayland is intended as a simpler replacement for X.
• GNOME and KDE are expected to be ported to it.

Ubuntu Frame

A fullscreen shell based on Wayland, used in kiosk, IoT and digital signage solutions, including smart mirrors, health kiosks, industrial panels and more.

Ubuntu Frame supports a range of applications built with GTK3/4, Qt5/6, Flutter, Electron and SDL2, and it also has a solution for applications based on HTML5, Java.