GNOME Display Manager (GDM) is a display manager (a graphical login manager) for the windowing systems X11 and Wayland. The X Window System by default uses the XDM display manager. However, resolving XDM configuration issues typically involves editing a

configuration file A configuration file, a.k.a. config file, is a computer file, file that stores computer data, data used to configure a software system such as an application software, application, a server (computing), server or an operating system. Some applic ...

. GDM allows users to customize or troubleshoot settings without having to resort to a

command line A command-line interface (CLI) is a means of interacting with software via command (computing), commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user ...

. Users can pick their session type on a per-login basis. GDM 2.38.0 is the last version that features customization with themes; subsequent releases do not support themes.

Software architecture

GDM is a display manager that implements all significant features required for managing attached and remote displays. GDM was written from scratch and does not contain any XDM or X Consortium code.

Components

GDM comprises the following components: * Chooser – a program used to select a remote host as the source for a remote display on the attached display (gdm-host-chooser) * Greeter – the graphical login window (provided by GNOME Shell) * Pluggable authentication module (PAM) *

X Display Manager Control Protocol In the X Window System, an X display manager is a graphical login manager which starts a login session on an X Window System, X server from the same or another computer. A display manager presents the user with a login, login screen. A sessio ...

(XDMCP)

Hidden features

Until version 2.22, GDM had a few

Easter eggs Easter eggs, also called Paschal eggs, are eggs that are Egg decorating, decorated for the Christian holiday of Easter, which celebrates the resurrection of Jesus. As such, Easter eggs are commonly used during the season of Eastertide (Easter ...

, in the form of strings to be entered in the username box. These can be found in the source file "gui/guilogin.c", in a function named "evil". * Dancing login – type "Start Dancing" to start, and "Stop Dancing" to stop. ** (This requires the standard greeter ("GTK+ Greeter"), rather than the graphical one ("Themed Greeter")). * "Gimme Random Cursor" – can be used repeatedly. ** This changes the mouse cursor to a randomly selected 1 of 77 different "cursor fonts" as defined in the X11 specification. * "Require Quarter" (or "Require Quater", for backward compatibility with a typo in the original), then log in normally – a dialog box that reads "Please insert 25 cents to log in." appears after entering the password. Clicking "OK" allows the login process to proceed as normal.

Queen of England

Some of the copyright notices of GDM refer to the "Queen of England", whom release announcements from version 2.2.1 also named as a maintainer. Subsequently, developers realised that the title " Queen of England" has not existed since the Acts of Union of 1707.

References

External links