Servers And Clients; The Power Of X - Red Hat LINUX 7.2 Reference Manual

Section 6.1:The Power of X 113
6 X Servers and Clients
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 X operates on your machine to provide advanced desktop functionality.

6.1 The Power of X

Linux began as a powerful server-based operating system, excelling at efficiently processing compli-
cated 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, in the home or busi-
ness.
In the UNIX world, windowing environments have existed for decades, predating many of the main-
stream operating systems. UNIX machines utilize the X Windows System, which uses a client-server
relationship for creating a graphical (GUI) environment for the user. An X server process is started that
the 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 certain things to be done 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.