Additional Resources - Red Hat ENTERPRISE LINUX 3 Reference Manual

Chapter 7. The X Window System
The user is returned to a text mode user session after logging out of X from runlevel 3.
7.5.2. Runlevel 5
When the system boots into runlevel 5, a special X client application, called a display manager is
launched. A user must authenticate using the display manager before any desktop environments or
window managers are launched.
Depending on the desktop environments installed on the system, three different display managers are
available to handle user authentication.
— The default display manager for Red Hat Enterprise Linux,
• gdm
language settings, shutdown, restart or log in to the system.
— KDE's display manager which allows the user to shutdown, restart or log in to the system.
• kdm
— A very basic display manager which only lets the user log in to the system.
• xdm
When booting into runlevel 5, the
referencing the
/etc/sysconfig/desktop
the
/usr/share/doc/initscripts- version-number /sysconfig.txt
version-number is the version number of the
Each of the display managers references the
Once the user logs into the system, the
ship of the console to the user. Then, the
of the tasks normally performed by the
ting system and user resources, as well as running the scripts in the
directory.
The user can specify which desktop environment they want to utilize when they authenticate using
the or display managers by selecting it from the Sessions menu item (accessed by selecting
gdm kdm
Main Menu Button [on the Panel] => Preferences => More Preferences => Sessions). If the desktop
environment is not specified in the display manager, the
and
.xsession .Xclients
to load. As a last resort, the
or window manager to use in the same way as runlevel 3.
When the user finishes an X session on the default display (
/etc/X11/xdm/TakeConsole
The original display manager, which continued running after the user logged in, takes control by
spawning a new display manager. This restarts the XFree86 server, displays a new login window, and
starts the entire process over again.
The user is returned to the display manager after logging out of X from runlevel 5.
For more information about how display managers control user authentication, refer to the
/usr/share/doc/gdm- version-number /README (where
version number for the

7.6. Additional Resources

There is a large amount of detailed information available about the XFree86 server, the clients that
connect to it, and the assorted desktop environments and window managers.
prefdm
/etc/X11/xdm/Xsetup_0
/etc/X11/xdm/GiveConsole
/etc/X11/xdm/Xsession
xinitrc
files in the user's home directory to decide which desktop environment
/etc/X11/xinit/Xclients
script runs and reassigns ownership of the console to the root user.
package installed) and the
gdm
script determines the preferred display manager by
file. A list of options for this file is available within
initscripts
script when starting X from runlevel 3, including set-
/etc/X11/xinit/xinitrc.d/
/etc/X11/xdm/Xsession
file is used to select a desktop environment
man page.
xdm
allows the user to configure
gdm
file
package).
file to set up the login screen.
script runs to assign owner-
script runs to accomplish many
script checks the
) and logs out, the
:0
version-number
99
(where
is the