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

Hidden features

Until version 2.22, GDM had a few Easter eggs, 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".

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.