The X Window System; Xfree86 - Red Hat ENTERPRISE LINUX 3 Reference Manual

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 systems.
The graphical environment for Red Hat Enterprise Linux is supplied by XFree86™, an open source
implementation of X. XFree86 is a large scale, rapidly developing project with hundreds of devel-
opers 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.
The X Window System uses a client-server architecture. The X server 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 X
server.

7.1. XFree86

Red Hat Enterprise Linux 3 uses XFree86 version 4.x as the base X Window System, which includes
many cutting edge XFree86 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.
Important
Red Hat Enterprise Linux no longer provides XFree86 version 3 server packages. Before
upgrading to the latest version of Red Hat Enterprise Linux, be sure the video card is compatible
with XFree86 version 4 by checking the Red Hat Hardware Compatibility List located online at
http://hardware.redhat.com/.
The files related to XFree86 reside primarily in two locations:
/usr/X11R6/
Contains X server and some client applications, as well as X header files, libraries, modules, and
documentation.
/etc/X11/
Contains configuration files for X client and server applications. This includes configuration files
for the X server itself, the older
components.
It is important to note that the configuration file for the newer Fontconfig-based font architecture
is
/etc/fonts/fonts.conf
configuring and adding fonts, refer to Section 7.4 Fonts.
Because the XFree86 server performs advanced tasks on a wide array of hardware, it requires de-
tailed configuration. The installation program installs and configures XFree86 automatically, un-
less the XFree86 packages are not selected for installation. However, if the monitor or video card

The X Window System

font server, the X display managers, and many other base
xfs
(which obsoletes the
/etc/X11/XftConfig
Chapter 7.
file). For more on