Chapter 5
Using Linux Graphical
Environments
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Objectives
In this chapter, you will:
• Understand how the X Window System functions
• Review the installation and settings of the X
Window System
• Use popular graphical desktop interfaces
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Valued Gateway
Client:
Understanding the X Window System
• The installation program automatically detects
your graphical hardware and configures the
graphical environment
• The foundation of that environment is the
software that communicates with the video card
and makes all other graphical interaction possible
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A Brief History of X
• The X Window System was developed by MIT
and DEC
• The X Window System was released as public
domain software in 1985
• The XFree86 Project created a version of X for
Intel-based Linux and Unix
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Technical Concepts behind X
• Developers of X designed a text-based
configuration file that lets the user write the
driver for any video card
• The Xfree86 Project and Linux vendors
developed configuration utilities to set up or
refine the graphical configuration
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Components of the X Window System
• List of components of X Window System:
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–
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–
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X server
X client
Window manager
Graphical libraries
Desktop environment
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Components of the X Window System
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Exploring X Components
• Each user can select a window manager,
desktop interface, and configuration options for
that desktop
• A window manager or desktop interface
provides the user interface to X
• Older, basic window managers like fvwm and
twm are still in use
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X Window Packages Installed with Red
Hat Linux 7.3
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The fvwm Window Manager
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A Sawfish Configuration Window in
Gnome
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The switchdesk Utility
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Exploring X Components
• Graphical libraries make it easier to create new
graphical applications by sharing programming
code and system resources
• Two graphical libraries are associated with the
Gnome and KDE Desktops:
– Qt (on which KDE is based)
– GTK+ (on which Gnome is based)
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Displaying X Clients Remotely
• The DISPLAY variable or display command-line
option controls remote display of X applications
• A remote host must permit an application to be
displayed by another computer using xhost or
xauth functionality
• With the xauth system you can restrict access to
those users on a remote system who have a
specific token (cookie) in order to use the X server
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Remotely Displaying an X Client
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Running the X Window System
• X Window System is configured during
installation
• To configure X after installation, you can use
utilities, such as Xconfigurator, xf86config, and
others
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Configuring X
• To use XFree86 packages, a window manager,
and a desktop interface, configure the X server
software to use a video card and a monitor
correctly
• You can make changes in the configuration of a
window manager or desktop environment
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The Configuration File
• When X Windows System is launched, it relies
on the XF86Config-4 configuration file plus a
number of scripts that define which X
applications should be launched
• The configuration file for XFree86 is located in
the /etc directory, in the /etc/X11 directory, or in
the /usr/X11R6/lib/X11
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Using Xconfigurator
• The Xconfigurator program creates an
XF86Config-4 file for your XFree86 X server
using a menu-driven text-based interface
• Xconfigurator probes your hardware and lets
you select choices from lists of options
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The Xconfigurator Utility
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Using xf86config
• Xf86config is a command-line configuration
utility
• The xf86config utility provides complete
flexibility in configuring the XFree86 software
• To launch xf86config, enter the utility name at
any Linux command line
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A Sample Question Posed by
xf86config
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Configuring X Using Other Resources
• For help configuring X, try the following:
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Contact knowledgeable people
Use specialized software
Search for information on the Internet
Buy a commercial X server
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Launching X
• The standard method to launch X is to execute the
startx command
• The startx command automatically executes a
number of other commands that launch the X
server and run the programs that make up the
graphical environment
• Each X client is started as a background
application
• A background application is an application that
does not prevent the program that started it from
going on to other tasks
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The Start-up Process for the
X Window System
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Fine Tuning X
• Each graphical application uses a number of X
resources such as windows, scroll bars, and
fonts
• A collection of default X resource settings
applies to all X applications
• The resource settings are compiled into a
resource database file
• The main resource database file is called appdefaults
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Fine Tuning X
• The xrdb command loads an initial X database
resource file or adds resource configuration
details from files
• The xset command controls aspects of X such
as keyboard repeat rate and screen blanking
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Using Desktop Interfaces
• A desktop interface is a graphical
environment that provides a collection of
functions and utilities
• Some types of information may be much
easier to work with in a graphical format
• Linux desktop interfaces are KDE and
Gnome
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The KDE Interface
• In 1996 Matthias Ettrich started the K Desktop
Environment (KDE) project
• KDE provides a convenient desktop interface with
icons, menus, and taskbars
• KDE includes a powerful file manager and many
graphical applications for configuring the KDE
interface
• The entire KDE project uses an OpenSource
license
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The KDE Desktop
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The KDE File Manager
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The KDE Control Center
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The Gnome Desktop
• Gnome is a desktop interface very similar to
KDE
• Gnome uses a GPL license
• Gnome provides a set of productivity
applications and system administration
utilities similar to those included with KDE
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The Gnome Desktop
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Configuring Gnome Features
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Using a Graphical Login Screen
• The graphical login prompt is provided by the
xdm program
• The xdm versions specific to KDE and
Gnome are called kdm and gdm, respectively
• xdm restarts automatically to provide a
graphical login screen
• xdm selects which programs to start based
on the session chosen by the user
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The GDM Configurator
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Summary
• The X Window System is a graphical environment
developed by MIT and DEC in 1985
• Components of X include
– X server: interacts with the video card
– X client: graphical application what uses the services of
the X server
• A window manager or desktop interface provides the
user interface to X
• Qt and GTK+ are the most widely used graphical
libraries
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Summary
• The DISPLAY variable or display command-line
option controls remote display of X applications
• Xconfigurator and xf86config utilities are used to
configure X after installation
• Graphical applications include X resources what
can be configured
• KDE and Gnome are popular desktop interfaces
• The graphical login prompt is provided by the
xdm program, or the kdm or gdm versions for
KDE or Gnome
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