Editing X display manager (section)

== History==
[[XDM (display manager)|XDM]] (the X Window Display Manager) originated in X11R3. This first version, written by [[Keith Packard]] of the MIT X Consortium, had several limitations, the most notable of which was that it could not detect when users switched X terminals off and on. In X11R3, XDM only knew about an X terminal from its entry in the {{mono|Xservers}} file, but XDM only consulted this file when it started. Thus every time a user switched a terminal off and on, the [[system administrator]] had to send a [[SIGHUP]] [[signal (computing)|signal]] to XDM to instruct it to rescan {{mono|Xservers}}.

XDMCP arrived with the introduction of X11R4 (December 1989). With XDMCP, the X server must actively request a display manager connection from the host. An X server using XDMCP therefore no longer requires an entry in {{mono|Xservers}}.