ch22.htm

linux-unix130.linux.and.unix.ebooks130 linux and unix ebookslinuxLearning Linux - Collection of 12 E

    EndSubsection

EndSection



# The Mono server



Section "Screen"

    Driver     "vga2"

    Device     "Generic VGA"

    Monitor    "Generic Monitor"

    Subsection "Display"

        Modes      "640x480"

        ViewPort    0 0

        Virtual     800 600

    EndSubsection

EndSection

</FONT></PRE>

<P>The <TT>Modes</TT> line in a video section can have up to 10 values. Be very careful

when modifying these values because a wrong setting might wind up destroying your

monitor! It does not matter if these values are not present because defaults can

be used. This would be a typical line to override defaults for a monitor:</P>

<PRE><FONT COLOR="#0066FF">&quot;640x400&quot; 28 640 480 728 776 480 480 482 494

</FONT></PRE>

<P>The 10 values in order from left to right are shown in the following section.

These values make sense only to video engineers or those folks who have to work with

a monitor not defined in the default modes. Check your monitor's hardware specifications,

and get the values from there to fill in these 10 parameters. These are the fields

to set:



<UL>

	<LI>The label for screen resolution; for example, 640x480 or 1024x768.

	<P>

	<LI>The clock frequency in MHz.

	<P>

	<LI>The Horizontal Display End in number of visible dots per line on the screen.

	<P>

	<LI>The Start Horizontal Retrace value. Specifies the number of pulses before the

	video sync pulse starts.

	<P>

	<LI>The End Horizontal Retrace value. Defines the end of the sync pulse.

	<P>

	<LI>The Horizontal Total value. The total number of dots per line invisible and visible.

	<P>

	<LI>The Vertical Display End value. The number of visible lines on the screen.

	<P>

	<LI>The Start Vertical Retrace value. The number of lines before the sync pulse starts.

	<P>

	<LI>The End Vertical Retrace value. The number of lines at the end of the sync pulse.

	<P>

	<LI>The Vertical Total value. The total number of lines, invisible plus visible,

	on the screen.

</UL>



<P>Multiscan monitors handle frequencies of 15 to 40 MHz. Some monitors work at a

72 MHz vertical scan to prevent the flicker. You have to be able to calculate the

frequency from the monitor's specification and come up with these numbers. A good

place to start would be the <TT>XFree86-HOWTO</TT> document on how to get these values.

Keep in mind that your video monitor is just a glorified television. You give it

wrong values, and you can fry it.

<H4 ALIGN="CENTER"><A NAME="Heading22<FONT COLOR="#000077">International Keyboard

Layout for XFree86</FONT></H4>

<P>XFree86 servers are able to read the key table from the Linux kernel, so you need

to set up only one keyboard layout file (for the kernel). There are some restrictions,

though; the kernel can support more keyboard functions than X11. X11 can modify only

one of the four key tables. This modifier is called <TT>ModeShift</TT>.</P>

<P>Configurable keys for the <TT>ModeShift</TT> modifier are LeftAlt, RightAlt (sometimes

referred to as AltGr), RightCtl, and ScrollLock.</P>

<P>Usually, the AltGr key is used for international keyboard modifications. To enable

the XFree86 server to read the RightAlt key table from the kernel, you should put

the following line in the <TT>.xinitrc</TT> file:</P>

<PRE><FONT COLOR="#0066FF">RightAlt &quot;ModeShift&quot;

</FONT></PRE>

<P>Besides supporting only one additional key map, X11 cannot use dead keys. A key

is called dead if, when it is typed, it does not print a character until a second

character is typed. A typical example is an accent key. Such keys are not supported

by X11, so you need to replace all dead key symbols with non-dead equivalents. Table

22.1 lists what you have to change. </P>

<CENTER>

<P><FONT SIZE="4"><B>Table 22.1. Key symbols. </B></FONT>

<TABLE BORDER="0">

	<TR ALIGN="LEFT" rowspan="1">

		<TD WIDTH="146" ALIGN="LEFT"><I>Dead</I></TD>

		<TD ALIGN="LEFT"><I>Non-Dead</I></TD>

	</TR>

	<TR ALIGN="LEFT" rowspan="1">

		<TD WIDTH="146" ALIGN="LEFT"><TT>dead_tilde</TT></TD>

		<TD ALIGN="LEFT">ASCII tilde</TD>

	</TR>

	<TR ALIGN="LEFT" rowspan="1">

		<TD WIDTH="146" ALIGN="LEFT"><TT>dead_grave</TT></TD>

		<TD ALIGN="LEFT">grave</TD>

	</TR>

	<TR ALIGN="LEFT" rowspan="1">

		<TD WIDTH="146" ALIGN="LEFT"><TT>dead_circumflex</TT></TD>

		<TD ALIGN="LEFT">ASCII circum</TD>

	</TR>

	<TR ALIGN="LEFT" rowspan="1">

		<TD WIDTH="146" ALIGN="LEFT"><TT>dead_acute</TT></TD>

		<TD ALIGN="LEFT">apostrophe</TD>

	</TR>

	<TR ALIGN="LEFT" rowspan="1">

		<TD WIDTH="146" ALIGN="LEFT"><TT>dead_diaeresis</TT></TD>

		<TD ALIGN="LEFT">dieresis</TD>

	</TR>

</TABLE>

</P>

</CENTER>

<P>Instead of supporting dead keys, XFree86 supports a Compose key. This feature

is described in the <TT>XFree86kbd</TT> man page. You can modify this feature by

assigning the <TT>Compose</TT> function to one of the keys. By default, the ScrollLock

key has the <TT>Compose</TT> function.</P>

<P>If you still want to have the dead keys on the console, you must use an <TT>xmodmap</TT>

file to map the keys to the correct symbols under X. This is also the method that

must be used with earlier versions of XFree86. On <TT>sunsite</TT> in the directory

<TT>/pub/Linux/X11/misc</TT>, you can find sample <TT>xmodmap</TT> files for several

languages. Note that you have to set the <TT>ModeShift</TT> modifier to get the right

key table working.</P>

<P>Read the <TT>kbd.FAQ</TT> that comes with the <TT>kbd</TT> package for Linux.

You will find many hints for modifying your keyboard layout on the console, as well

as for X.

<CENTER>

<H3><A NAME="Heading23<FONT COLOR="#000077">The .xinitrc File</FONT></H3>

</CENTER>

<P>To use X, you need a startup file that calls the local modifications, the window

manager, and an application you want to use right after X has started. If you are

using <TT>startx</TT> (or <TT>runx</TT>) to start X, this startup file is called

<TT>xinitrc</TT>. There is a standard <TT>xinitrc</TT> file, <TT>/usr/lib/X11/xinit/xinitrc</TT>,

which is the traditional location for this file. The Linux file system standard in

<TT>setup</TT> places this file in <TT>/etc/X11/xinit/xinitrc</TT> to allow a read-only

mounted <TT>/usr</TT> partition, so look at that location first.</P>

<P>If you are not content with what this file does (for instance, if you want to

use a different window manager), you should copy it to the file <TT>.xinitrc</TT>

in your <TT>home</TT> directory. After copying the file, you can edit it. Look at

the man pages for <TT>startx</TT> and <TT>xinit</TT> for more information.</P>

<P>Note that both the <TT>.xinitrc</TT> and the <TT>.Xresources</TT> files must be

readable and executable, so run the following command on these files after editing

them. You have to run the <TT>chmod</TT> command only once on the application.</P>

<PRE><FONT COLOR="#0066FF">$ chmod u+rx .xinitrc .Xresources

</FONT></PRE>

<P>This command makes these files executable.</P>

<P>Listing 22.6 shows a sample <TT>xinitrc</TT> file.

<CENTER>

<H3><A NAME="Heading24<FONT COLOR="#000077">Listing 22.6. A sample .xinitrc

file.</FONT></H3>

</CENTER>

<PRE><FONT COLOR="#0066FF">

     1 #!/bin/sh

     2 # $XConsortium: xinitrc.cpp,v 1.4 91/08/22 11:41:34 rws Exp $

     3 # modified by obz



     4 userresources=$HOME/.Xresources

     5 usermodmap=$HOME/.Xmodmap

     6 sysresources=/usr/lib/X11/xinit/.Xresources

     7 sysmodmap=/usr/lib/X11/xinit/.Xmodmap



     8 # merge in defaults and keymaps



     9 if [ -f $sysresources ]; then

    10     xrdb -merge $sysresources

    11 fi



    12 if [ -f $sysmodmap ]; then

    13     xmodmap $sysmodmap

    14 fi



    15 if [ -f $userresources ]; then

    16     xrdb -merge $userresources

    17 fi



    18 if [ -f $usermodmap ]; then

    19     xmodmap $usermodmap

    20 fi



    21 # Set the background to a dull gray

    22 if [ -f /usr/bin/X11/xsetroot ]; then

    23 xsetroot -solid gray32

    24 fi



    25 if [ -f /usr/bin/X11/xclock ]; then

    26        xclock -geometry 80x80 &amp;

    27 fi



    28 olvwm &amp;

    29 # fvwm &amp;



    30 xterm  -e /bin/bash

</FONT></PRE>

<P>The line numbers in this listing have been added for your benefit. Let's look

at these lines in greater detail.</P>

<P>Lines 4-7 set the resource environment variables for the X Window installation

for your system. Change these to the path of your system's X Window system distribution.</P>

<P>Lines 9-20 check for the existence of these resources and then run the appropriate

program, xmodmap or xrdb, with these resources as parameters. I cover both xmodmap

and xrdb in Chapter 23, &quot;Using Motif.&quot; For now, you can use this the way

it stands.</P>

<P>Lines 22-24 check for the xsetroot program. If it's present, these lines execute

it to set the background to a solid color, <TT>gray32</TT>.</P>

<P>The <TT>olvwm &amp;</TT> command in line 28 starts the OPEN LOOK window manager.

If you want to use <TT>fvwm</TT> instead of <TT>olvwm</TT>, uncomment line 29 and

comment line 28 instead. The window manager must be run in the background if you

have more commands following this one.</P>

<P>Line 30 starts a terminal to work with. Because this is the last line in the <TT>.xinitrc</TT>

file, exiting this terminal causes your X session to stop. If you want to start more

<TT>xterms</TT>, you can start them from within this <TT>xterm</TT>.</P>

<P>A simpler <TT>.xinitrc</TT> file to start with would be this:</P>

<PRE><FONT COLOR="#0066FF">xterm -name Console &amp;



olvwm

</FONT></PRE>

<P>You can then enhance this <TT>.xinitrc</TT> file with what you want.

<CENTER>

<H3><A NAME="Heading25<FONT COLOR="#000077">The Personal X Resource File</FONT></H3>

</CENTER>

<P>Sometimes you won't be content with default settings for applications that don't

have a configuration file of their own. You can change some of these defaults by

setting X resources in the <TT>.Xresources</TT> file in your <TT>home</TT> directory.



<DL>

	<DT></DT>

</DL>





<DL>

	<DD>

<HR>

<A NAME="Heading26<FONT COLOR="#000077"><B>NOTE: </B></FONT>You should know

	what effects setting the resources will have on the programs you use. Read the man

	pages for the program and for xrdb before editing the <TT>Xresources</TT> file. See

	Chapter 2, &quot;Types of Linux,&quot; and Chapter 25, &quot;Ghostscript,&quot; for

	more information about X resources. 

<HR>



</DL>



<P>A resource file looks like an application default file. The difference is that

in the resource file, resources for several applications are set. You should use

the full names (Progname.Resourcename) instead of abbreviating the program name with

an asterisk. Examples of application default files can be found in the <TT>/usr/X386/lib/X11/app-defaults</TT>

directory. The resources available for a single application are usually shown in

the man pages for that application.</P>

<P>If you are running a color server, you might want to put the following lines into

your <TT>.Xresources</TT> file if some programs start in black and white:</P>

<PRE><FONT COLOR="#0066FF">#ifdef COLOR

*customization: -color

#endif

</FONT></PRE>

<P>If this change is made, the program Foo will read both the Foo and the Foo-color

application default file from <TT>/usr/X386/lib/X11/app-defaults</TT>. The usual

behavior is for Foo only to be read.



<DL>

	<DT></DT>

</DL>





<DL>

	<DD><A NAME="Heading27 

<HR>

<FONT COLOR="#000077"><B>NOTE:</B> </FONT>If you are running a color server, the

	preceding code definitely should be added to the system <TT>Xresources</TT> file.

	You might mention that to whomever maintains the program you are running. 

<HR>



</DL>



<P>Note that the black-and-white color scheme of a program might be caused by the

program rather than its resources.</P>

<P>The <TT>-xrm</TT> can be used with most X programs to override the parameters

set in your .<TT>Xresources</TT> file. The usage is</P>

<PRE><FONT COLOR="#0066FF">-xrm &quot;resource&quot;

</FONT></PRE>

<P>Alternatively, you can use the <TT>xrdb</TT> filename command to make any changes

you have made in filename apply to your current session.

<CENTER>

<H3><A NAME="Heading28<FONT COLOR="#000077">Using xdm</FONT></H3>

</CENTER>

<P>If you want to run X on your system all the time, you could run xdm from the system

startup. xdm is preconfigured on most systems, so you should not have to edit any

of the xdm configuration files. You can run xdm from the command line at the console