Harman Patil (Editor)

GNOME Display Manager

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Written in
  
C

GNOME Display Manager

Developer(s)
  
The GNOME Project (William Jon McCann, Brian Cameron, Ray Strode)

Stable release
  
3.22.3 (9 November 2016; 3 months ago (2016-11-09)) [±]

Preview release
  
3.23.91 (1 March 2017; 7 days ago (2017-03-01)) [±]

Operating system
  
Unix-like (includes: BSD, Linux, Solaris)

Type
  
X display manager Linux on the desktop

GDM (the GNOME Display Manager) is a display manager (a graphical login program) for the windowing systems X11 and Wayland.

Contents

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

The GNOME Display Manager (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

GNOME Display Manager (GDM) is the name, which is used to describe the software package as a whole. It comprises the following components:

  • Chooser – a program used to select a remote host for managing a display remotely 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 (XDMCP)

    • 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".

  • Dancing login – type "Start Dancing" to start, and "Stop Dancing" to stop. (This requires the standard greeter, rather than the graphical one).
  • "Gimme Random Cursor" – can be used repeatedly.
  • "Require Quarter" (or "Require Quater", for backward compatibility with a typo in the original), then log in normally – a dialog box appears after entering the password.

    • 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.

    Removed features

    As of version 3.0 the GNOME display manager switched to using AccountService for saving the user's selected session rather than storing it in the user's home directory, effectively making it unusable in a networked environment.

    References

    GNOME Display Manager Wikipedia
    (Text) CC BY-SA