Is a "Display Manager" the same thing as a "Session Manager"?
Answer: No they are not the same. The
session managermanages your session, and the
display manager is responsible for providing you with a login interface.
Likewise, is a "Windowing system" the same thing as a "Window manager"?
Answer: No they are different. The
window mangager sits on top of the
Window system: Each currently running application is assigned a usually resizeable and usually rectangular shaped surface of the display to present its graphical user interface to the user; these windows may overlap each other, as opposed to a tiling interface where they are not allowed to overlap.
window manager: When a window manager is running, some kinds of interaction between the X server and its clients are redirected through the window manager. In particular, whenever an attempt to show a new window is made, this request is redirected to the window manager, which decides the initial position of the window
X Window System, an X session manager is a session management program, a program that can save
and restore the current state of a set of running applications.
X window manager
An X window manager is a window manager which runs on top of the X Window System, a windowing system
mainly used on Unix-like systems.
- Stacking window managers
- Tiling window managers
- Compositing window managers
- Virtual window managers
- Window managers that are extensible
The user can choose between various
third-party window managers, which differ from one another in several ways, including:
customizability of appearance and functionality:
textual menus used to start programs and/or change options
docks and other graphical ways to start programs
multiple desktops and virtual desktops (desktops larger than the
physical monitor size), and pagers1 to switch between them
consumption of memory and other system resources
degree of integration with a desktop environment, which provides a
more complete interface to the operating system, and provides a range
of integrated utilities and applications.
While the main aim of a window manager is to manage the windows, many window managers have additional features such as handling mouse clicks in the root window, presenting panes and other visual elements, handling some keystrokes (e.g., Alt-F4 may close a window), deciding which application to run at start-up, etc.
(there is a list of display managers in the source website)
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. There are various implementations of
display managers, just as there are various types of window managers and desktop environments.
There is usually a certain amount of customization and themeability available with each one.
X display manager
X Window System, an X display manager runs as a program that allows the starting of a session
on an X server from the same or another computer.
display manager presents the user with a login screen which prompts for a username and password.
A session starts when the user successfully enters a valid combination of username and password.
The X window system
Debian manual for x window system
X Window System (X11, X, and sometimes informally X-Windows) is a windowing system for bitmap displays, common on UNIX-like computer operating systems.
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.