While the heart of Red Hat Linux is the kernel, for workstation users, the X
environment is the face of the operating system. The kernel provides the
engine for everything that happens, managing processes and resources
virtually unseen. However, the day-to-day Linux users spend the majority
of their time in a graphical desktop environment, opening applications,
resizing windows, and scrolling through text.
This chapter is designed to serve as an introduction to the
behind-the-scenes world of XFree86 and how the
X Window System — also called
X — operates on your machine to provide
advanced desktop functionality.
Linux began as a powerful, server-based operating system, excelling at
efficiently processing complicated programs requiring high CPU
utilization and handling requests from hundreds or thousands of clients
through network connections. However, because of its open nature and
stability, Linux has quickly developed into a popular GUI-based
operating system for workstations, both in the home or in the workplace.
In the UNIX world, windowing environments have existed for decades,
predating many of the current mainstream operating systems. UNIX
machines utilize the X Window System, which uses a client-server
relationship for creating a graphical user interface (GUI) for the
user. An X server process is started that
X client processes can connect to via a network
or local connection. The server process handles the communication with
the hardware, such as the video card, monitor, keyboard, and mouse. The
X client exists in the userspace, issuing requests to the X server for
tasks to be performed using the hardware it controls.
On Red Hat Linux systems, the XFree86 server fills the role of the X server. As
an open source software project operating on a grand scope with hundreds
of developers around the world, XFree86 features rapid development, a
wide degree of support for various hardware devices and architectures,
and the ability to run on different operating systems and platforms.
Most Red Hat Linux desktop users are unaware of the XFree86 server running on
their system. They are much more concerned with the particular desktop
environment in which they spend most of their time. The Red Hat Linux
installation program does an excellent job of configuring your XFree86
server during the installation process, ensuring that X performs
optimally when first started.
The X server performs many difficult tasks using a wide array of
hardware, requiring a very detailed configuration of certain files. If
some aspect of your system changes, such as the monitor or video card,
XFree86 will need to be reconfigured. In addition, if you are
troubleshooting a problem with XFree86 that cannot be solved using a
configuration utility, such as Xconfigurator, you
may need to access these configuration files.
 | Caution |
|---|
| | Xconfigurator should not be used to configure
XFree86 while the X server is active. If your system defaults to
starting up directly into X or runlevel 5, you should switch to
runlevel 3 prior to running Xconfigurator. If your
system defaults to starting up in text mode, or runlevels 1 through 4,
you should make sure that the X server is not running while
configuring X via Xconfigurator. Failure to stop
the X server before running Xconfigurator can cause
hardware lockups and possibly data corruption.
|
