Editing XDM (display manager)

{{Short description|Linux display manager}}
{{Hatnote|This article is about the X Display Manager. XDM also refers to the [[XML]] data model used in [[XPath 2.0]], [[XSLT 2.0]], and [[XQuery]].}}
{{Confused|X display manager}}
{{Infobox software
| name                   = XDM
| title                  = XDM
| logo                   = <!-- Image name is enough -->
| logo caption           = 
| logo_size              = 
| logo_alt               = 
| screenshot             = Xdm Screenshot.png
| caption                = A screenshot of an XDM login screen
| screenshot_size        = 350px
| screenshot_alt         = 
| collapsible            = 
| author                 = [[Keith Packard]]
| developer              = [[X.Org Foundation]]
| released               = {{Start date and age|1988|10}}
| discontinued           = 
| latest release version = {{wikidata|property|preferred|references|edit|Q30339330|P348|P548=Q2804309}}
| latest release date    = {{start date and age|{{wikidata|qualifier|preferred|single|Q30339330|P348|P548=Q2804309|P577}}}}
| latest preview version = {{wikidata|property|preferred|references|edit|Q30339330|P348|P548=Q51930650}}
| latest preview date    = {{wikidata|qualifier|preferred|single|Q30339330|P348|P548=Q51930650|P577}}
| programming language   = [[C (programming language)|C]], [[C++]]
| operating system       = 
| platform               = 
| size                   = 
| language               = 
| language count         = <!-- DO NOT include this parameter unless you know what it does -->
| language footnote      = 
| genre                  = [[X display manager]]
| license                = [[MIT License]]
| alexa                  = 
| website                = <!-- {{URL|example.org}} -->
| standard               = 
| AsOf                   = 
}}

The '''X Display Manager (XDM)''' is the default [[X display manager|display manager]] for the [[X Window System]]. It is a bare-bones X display manager. It was introduced with X11 Release 3 in October 1988, to support the standalone [[X terminal]]s that were just coming onto the market. It was written by [[Keith Packard]].

== Functions ==
XDM is used to boot an X.org based [[desktop environment]].<ref>{{Cite web |last=Impson |first=Jeremy |date=2002-01-01 |title=VNC, Transparently |url=https://www.linuxjournal.com/article/5499 |access-date=2024-05-13 |website=www.linuxjournal.com}}</ref> It can control a display directly or indirectly in order to start an X session and supports remote login.<ref name=":0">{{Cite book |last1=Anderson |first1=Robin |url=https://books.google.com/books?id=pO6rRW2736AC&dq=%22XDM%22+display+manager&pg=PA451 |title=Unix Unleashed |last2=Johnston |first2=Andy |date=2002 |publisher=Sams Publishing |isbn=978-0-672-32251-8 |language=en}}</ref> XDM is initialized on system startup.<ref name=":1">{{Cite web |last=Edward |first=Robert |date=2024-03-18 |title=What Are Display Managers and How Do They Work? |url=https://www.baeldung.com/linux/display-managers-explained |access-date=2024-05-13 |website=Baeldung}}</ref>

It can be edited through the use of a configuration file, modules, or scripts.<ref>{{Cite book |last1=Quercia |first1=Valerie |url=https://books.google.com/books?id=ey_58UlP7QYC&dq=%22XDM%22+display+manager&pg=PA562 |title=X Users Guide Motif R5: Motif Edition |last2=O'Reilly |first2=Tim |date=1993 |publisher="O'Reilly Media, Inc." |isbn=978-1-56592-015-6 |language=en}}</ref><ref>{{Cite book |last=Barkakati |first=Naba |url=https://books.google.com/books?id=xBANKuFJWtUC&dq=%22XDM%22+display+manager&pg=PA251 |title=Red Hat Fedora Linux Secrets |date=2005-09-19 |publisher=John Wiley & Sons |isbn=978-0-471-77492-1 |language=en}}</ref> The configuration file is usually found in /usr/lib/X11/xdm/xdm-config.<ref>{{Cite book |last=Levi |first=Bozidar |url=https://books.google.com/books?id=KRDNBQAAQBAJ&dq=%22XDM%22+display+manager&pg=PA549 |title=UNIX Administration: A Comprehensive Sourcebook for Effective Systems & Network Management |date=2002-05-29 |publisher=CRC Press |isbn=978-1-4200-0003-0 |language=en}}</ref>

== History ==
XDM is one of the earliest display managers for Linux.<ref name=":1" /> It was developed by Keith Packard after he joined the X Consortium due to his frustration using a text-based environment to try and configure X.<ref>{{Cite web |last=O'Neal |first=Miles |date=1996-07-10 |title=Taming The X Display Manager |url=http://www.rru.com/~meo/pubsntalks/xrj/xdm.html |access-date=2024-05-13 |website=www.rru.com}}</ref>

XDM is available but unused on most systems because of its rudimentary nature.<ref>{{Cite web |last=Gerganov |first=Hiks |date=2024-03-18 |title=Linux Display Managers (LightDM, SLiM, XDM, GDM, SDDM, KDM, Ly): Install and Uninstall Guide |url=https://www.baeldung.com/linux/display-managers-install-uninstall |access-date=2024-05-13 |website=Baeldung}}</ref> Desktop environments released afterwards tended to include their own display manager, such as dtlogin on [[Common Desktop Environment|CDE]].<ref name=":0" />

==See also==
{{Portal|Free and open-source software}}
* [[X display manager]]
* [[GNOME Display Manager|GDM]]
* [[KDE Display Manager|KDM]]

==References==
{{Reflist}}

==Further reading==
* {{cite book
 | last1         = Mui
 | first1        = Linda
 | last2         = Pearce
 | first2        = Eric
 | name-list-style = amp
 | title         = X Window System Volume 8: X Window System Administrator's Guide for X11 Release 4 and Release 5|edition=3rd
 | publisher     = O'Reilly and Associates
 | date          = July 1993
 | type          = softcover
 | isbn          = 0-937175-83-8}}

{{XWinSys}}

{{DEFAULTSORT:Xdm (Display Manager)}}

[[Category:Free system software]]
[[Category:Software using the MIT license]]
[[Category:X display managers]]
[[Category:Free software programmed in C]]
[[Category:Free software programmed in C++]]