- What is Desktop Environment?
A desktop environment bundles together a variety of components to provide common graphical user interface elements such as icons, toolbars, wallpapers, and desktop widgets. Additionally, most desktop environments include a set of integrated applications and utilities.
- What is Desktop Manager?
A window manager (WM) is system software that controls the placement and appearance of windows within a windowing system in a graphical user interface (GUI). It can be part of a desktop environment (DE) or be used standalone.
- What is Display Manager?
A display manager, or login manager, is typically a graphical user interface that is displayed at the end of the boot process in place of the default shell
- What is X window system, server, X11 and Xorg?
X provides the basic framework for a GUI environment: drawing and moving windows on the display device and interacting with a mouse and keyboard. X does not mandate the user interface — this is handled by individual programs. As such, the visual styling of X-based environments varies greatly; different programs may present radically different interfaces.
- What is the relation between the above, which runs/depends on which?
display manager > X > desktop
Display manager needs to run first, as it needs to perform an authentication check (login), i.e. if authentication fails then the rest of the desktop systems will not be displayed.
Then X runs, and spawns the desktop environment as child processes.
- How can I check what Desktop Manager and Display Manager I am using in Raspbian?
Try checking the settings in