Chapter 7. The X Window System
While the heart of Red Hat Enterprise Linux is the kernel, for
many users, the face of the operating system is the graphical
environment provided by the X Window
System, also called X.
Various windowing environments have existed in the UNIX™ world for decades, predating many of
the current mainstream operating systems. Through the years, X has
become the dominant graphical environment for UNIX-like operating
The graphical environment for Red Hat Enterprise Linux is
supplied by the X.Org Foundation, an open
source consortium created to manage development and strategy for
the X Window System and related technologies. X.Org is a large
scale, rapidly developing project with hundreds of developers
around the world. It features a wide degree of support for a
variety of hardware devices and architectures, and can run on a
variety of different operating systems and platforms. This release
for Red Hat Enterprise Linux specifically includes the X11R6.8
release of the X Window System.
The X Window System uses a client-server architecture. The
X server (the Xorg binary) listens for connections from X client applications via a network or local
loopback interface. The server communicates with the hardware, such
as the video card, monitor, keyboard, and mouse. X client
applications exist in the user-space, creating a graphical user interface (GUI) for the user and passing user requests to the
Red Hat Enterprise Linux 4 uses the X11R6.8 release as the base
X Window System, which includes many cutting edge X.Org technology
enhancements, such as 3D hardware acceleration support, the XRender
extension for anti-aliased fonts, a modular driver-based design,
and support for modern video hardware and input devices.
Red Hat Enterprise Linux no longer provides the XFree86™ server packages. Before upgrading
to the latest version of Red Hat Enterprise Linux, be sure that the
video card is compatible with the X11R6.8 release by checking the
Red Hat Hardware Compatibility List located online at http://hardware.redhat.com/.
The files related to the X11R6.8 release reside primarily in two
Contains X server and some client applications, as well as X
header files, libraries, modules, and documentation.
Contains configuration files for X client and server
applications. This includes configuration files for the X server
itself, the fs font server, the X display
managers, and many other base components.
It is important to note that the configuration file for the
newer Fontconfig-based font architecture is /etc/fonts/fonts.conf (which obsoletes the
/etc/X11/XftConfig file). For more on
configuring and adding fonts, refer to Section 7.4 Fonts.
Because the X server performs advanced tasks on a wide array of
hardware, it requires detailed configuration. The installation
program installs and configures X automatically, unless the X11R6.8
release packages are not selected for installation. However, if the
monitor or video card changes, X must to be reconfigured. The best
way to do this is to use the X Configuration
To start the X Configuration Tool
while in an active X session, go to the (on the Panel) => => . After using the
X Configuration Tool during an X
session, changes takes effect after logging out and logging back
in. For more about using the X Configuration
Tool, refer to the chapter titled X Window
System Configuration in the Red Hat
Enterprise Linux System Administration Guide.
In some situations, reconfiguring the X server may require
manually editing its configuration file, /etc/X11/xorg.conf. For information about the
structure of this file, refer to Section 7.3 X Server