Open Source Systems

Configuring X Window System

Submitted By Kiran Subramaniam S III Year BE/CSE AC07UCS033

Configuring
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What is X? X is the standard graphical user interface for Linux. Like other graphical user interfaces such as Microsoft Windows and Mac OS X lets you interact with programs by using a mouse (or other pointing device) to point and click, providing a simple means of communicating with your computer. Originally implemented as a collaborative effort of Digital Equipment Corporation and Massachusetts Institute of Technology, X was first released in 1987. Subsequently, the X Consortium, Inc. became responsible for the continued development and publication of X. Despite its age, X is a remarkable and very modern software system: a cross-platform, network-oriented graphical user interface. It runs on a wide variety of platforms, including essentially every variety of Unix. X Clients are available for use, for example, under Windows 3.x, 9x, and NT. The sophisticated networking capabilities of X let you run a program on one computer while viewing the graphical output on another computer, connected to the first via a network. With the advent of the Internet, which interconnected a sizable fraction of the computers on the planet, X achieved a new height of importance and power. Most Linux users run XFree86, a freely available software system compatible with X. XFree86 was developed by the XFree86 software team, which began work in 1992. In 1994, The XFree86 Project assumed responsibility for ongoing research and development of XFree86.

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Installing X Getting a proper X Window System up and running used to be a real challenge on Linux, almost a rite of passage. Today, device drivers are available for a much wider array of hardware, and configuration tools to assist in the setup process have greatly improved. While still tricky at times - especially with unusual hardware - X setup and configuration is no longer the daunting process it once was, and should be relatively easy. You'll go through two stages before you have X successfully running. The first stage involves installing the needed programs that enable X to run. These can be grouped into several categories: • Basic XFree86 program • X servers • Window Managers • Applications • Fonts This stage is very straightforward and can even be done as part of the basic installation process, if you select the relevant X packages during that step. In the second stage you configure X to run properly on your system. This is a matter of identifying an X server compatible with your graphics card, and tuning the server for your graphics card. If you have a common card and all the documentation for it, this second stage will be relatively simple. Missing information makes the process harder, but not impossible. Once you've installed the necessary packages, you're ready to configure X. 3


Configuring
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Configuring X When you install the xserver-common package, xf86config is automatically launched. However, you can launch the program any time you like. To do so, log in as root and type the command: xf86config

Below is shown the beginning of the xf86config dialog. As you can see, xf86config is a text-mode program; it does not support use of the mouse and it presents its questions teletype-style, using black-and-white text. In working with xf86config, you may find that your Backspace key doesn't work as expected. If so, use CtrlBackspace instead. The beginning of the xf86config dialog

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Next, xf86config asks you to specify the type of mouse attached to your system, as shown above. Type the number associated with your choice, and press Enter. For non-mouse pointing devices found on many laptops, you should most likely select PS/2 Mouse. Specifying the mouse type

If you selected the Logitech MouseMan mouse, you should enable its third button by responding y to the question asking whether ChordMiddle should be enabled, as shown in figure below. Specifying the ChordMiddle option

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If your mouse has only two buttons, you should enable emulation of a three-button mouse by responding y to the question asking about Emulate3Buttons, as shown in below figure. If you enable this option you can simultaneously press both the buttons of your mouse to emulate pressing the third button. Specifying emulation of a three-button mouse




Next, you must specify the device file associated with the mouse, as shown in below figure. The install program should have associated your system's mouse with the device /dev/mouse, which is the default choice. Simply press Enter to continue. Specifying the mouse device

As described by the output shown in below figure, X provides special support for using extended keyboards. If you use a special keyboard layout to support national characters, you can type y to use xkb, which simplifies changing the keyboard map. After making your choice, press Enter to continue.

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Specifying use of the keyboard extension




As shown in below figure, xkb supports a variety of keyboard encodings, or keymaps. Type the number that corresponds to the type of keyboard attached to your system, and press Enter.

Specifying the keymap




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Next, as shown in below figure, you must specify two characteristics of your system's monitor: its vertical refresh rate (VertRefresh) and horizontal sync rate (HorizSync). You can find these values by: Consulting your monitor's documentation Consulting the file /usr/doc/xserver-common/Monitors.gz, which may list your monitor. Use gunzip to uncompress the file and ae or another text editor to view it. Viewing the monitor's manufacturer's web support page Posting a question to the newsgroup comp.os.linux.setup Contacting the monitor manufacturer's technical support group and requesting the information

To specify the monitor's characteristics, press Enter.

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Preparing to specify monitor characteristics


 


First, you must specify the horizontal sync rate of your monitor, as shown in figure below. Type the number associated with your choice and press Enter. If you're unsure of your monitor's horizontal sync range, but certain that it supports 800×600 resolution, specify range 2. To specify a range other than those listed, you can select choice 11; if you do so, you'll be prompted to enter the low and high values of the horizontal sync range. WARNING: Often, otherwise similar monitor models have different horizontal sync rates. It is crucial that you accurately determine the horizontal sync rate of your monitor. If you configure X to use an inappropriate horizontal sync rate, you can permanently damage your monitor.

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Specifying the horizontal sync rate




Next, as shown in figure below, you must specify the vertical sync (refresh) rate. Type the number associated with your choice and press Enter. If you're unsure of your monitor's vertical sync range, specify range 1, which is the most conservative. To specify a range other than those listed, you can select choice 5; if you do so, you'll be prompted for the low and high values of the vertical sync range. Specifying the vertical sync rate


 


You must now specify identification and description strings for your monitor, as shown in figure below. You can enter any text you like. Press Enter after typing each string.
 
 
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Specifying the monitor identification and description strings 





Next, you must specify your video card and its characteristics. The explanations provided by xf86config, shown in figure below, point out that you can choose to select your card from a database. However, even if you do so, you'll be given the opportunity to specify non-standard values. Unless you have a specific reason for doing so, you should not override the values in the database. Moreover, you should be careful to choose only the database entry that exactly matches your card; cards having similar model names may have significantly different hardware characteristics. Preparing to examine the card database


 
 


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Below figure shows the screen you use to choose your card. Simply type the number associated with your card and press Enter. If you suspect that your card appears on a subsequent page, press q to page forward through the database. If you accidentally page past your card, simply continue moving forward; when the program reaches the last entries of the database, it cycles back to the beginning. Examining the card database




After you choose your video card, xf86config reports your choice. As in below figure, xf86config may provide instructions, such as "Do NOT probe clocks." It's a good idea to write these down so that you remember to observe them even after they've scrolled off the screen.

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The selected card definition




Next, you must specify the X server you want to use, as shown in figure below. Consult Table C.1 to determine the appropriate server. Type the number associated with the server and press Enter to continue. If you specify choice 4, you'll be prompted to specify which accelerated server you want to use. If you're in doubt, specify server 3, the XF86_SVGA server; unless your video card or monitor are quite old, they're likely to support 256-color SVGA. Specifying the server


 
 
 
 
 
 
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Specifying the modes




Finally, as shown in figure below, xf86config is ready to write the configuration file it has prepared. Generally, you should let it write the file to /etc/X11/XF86Config; simply type y and press Enter. However, if you prefer, you can type n and specify a different directory or filename. Writing the configuration file


 


Once the file has been written, you're ready to start X.

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