Here is an excerpt from a typical Files section. The lines beginning with a hash mark (#) are comments and are not processed by X. Only two configuration items—RgbPath and FontPath—are present.

Section "Files"

# The location of the RGB database. Note, this is the name of the
# file minus the extension (like ".txt" or ".db"). There is normally
# no need to change the default.

    RgbPath "/usr/X11R6/lib/X11/rgb"

# Multiple FontPath entries are allowed (they are concatenated together)
# By default, Red Hat 6.0 and later now use a font server independent of
# the X server to render fonts.

    FontPath   "unix/:7100"

EndSection

RgbPath gives the path of a file that contains names for commonly used colors. The actual name of the file is rgb.txt, not merely rgb. Here is an excerpt from the file:

255 250 250             snow
248 248 255             ghost white
248 248 255             GhostWhite
245 245 245             white smoke
245 245 245             WhiteSmoke

The file uses three numbers to represent a color, via the so-called RGB color scheme. The numbers represent the amount of red, green, and blue in a color. The numbers range from 0 to 255. The RGB value 0,0,0 corresponds to black, whereas the RGB value 255,255,255 corresponds to white. The color called snow is very nearly white.

FontPath can specify paths containing font files. However, Red Hat Linux uses the X Font Server. So, instead of font paths, what appears is merely a reference to the font server, which operates on port 7100.

The typical ServerFlags section contains nothing but comments. Here’s an example:

Section "ServerFlags"

    # Uncomment this to cause a core dump at the spot where a signal is 
    # received. This may leave the console in an unusable state, but may
    # provide a better stack trace in the core dump to aid in debugging
    #NoTrapSignals

    # Uncomment this to disable the <Crtl><Alt><BS> server abort sequence
    # This allows clients to receive this key event.
    #DontZap

    # Uncomment this to disable the <Crtl><Alt><KP_+>/<KP_-> mode switching
    # sequences. This allows clients to receive these key events.
    #DontZoom

EndSection

The Keyboard section specifies the configuration items related to the keyboard. As explained by the comments in the Keyboard section, you can use keyboard configuration items to alter the operation of control keys, such as the Alt key. You can also specify the model and layout of the keyboard. However, you’ll likely need to install special fonts to be able to use variant keyboard types. Therefore, it’s much easier to use Xconfigurator than to attempt to hack the configuration file.

Here’s a typical Keyboard section:

Section "Keyboard"

    Protocol    "Standard"

    # When using XQUEUE, comment out the above line, and uncomment the
    # following line
    #Protocol   "Xqueue"

    AutoRepeat  500 5

    # Let the server do the NumLock processing. This should only be 
    # required when using pre-R6 clients
    #ServerNumLock

    # Specify which keyboard LEDs can be user-controlled (eg, with xset(1))
    #Xleds      1 2 3

    #To set the LeftAlt to Meta, RightAlt key to ModeShift, 
    #RightCtl key to Compose, and ScrollLock key to ModeLock:

   LeftAlt         Meta
   RightAlt        Meta
   ScrollLock      Compose
   RightCtl        Control

# To disable the XKEYBOARD extension, uncomment XkbDisable.

#    XkbDisable

# To customise the XKB settings to suit your keyboard, modify the
# lines below (which are the defaults).  For example, for a non-U.S.
# keyboard, you will probably want to use:
#    XkbModel    "pc102"
# If you have a US Microsoft Natural keyboard, you can use:
#    XkbModel    "microsoft"
#
# Then to change the language, change the Layout setting.
# For example, a German layout can be obtained with:
#    XkbLayout   "de"
# or:
#    XkbLayout   "de"
#    XkbVariant  "nodeadkeys"
#
# If you'd like to switch the positions of your capslock and
# control keys, use:
#    XkbOptions  "ctrl:swapcaps"

# These are the default XKB settings for XFree86
#    XkbRules    "xfree86"
#    XkbModel    "pc101"
#    XkbLayout   "us"
#    XkbVariant  ""
#    XkbOptions  ""

   XkbKeycodes     "xfree86"
   XkbTypes        "default"
   XkbCompat       "default"
   XkbSymbols      "us(pc101)"
   XkbGeometry     "pc"
   XkbRules        "xfree86"
   XkbModel        "pc101"
   XkbLayout       "us"
EndSection

The Pointer section specifies the mouse or other pointing device. The most important configuration items are Protocol and Device. Here’s a typical Pointer section:

Section "Pointer"
    Protocol    "Microsoft"
    Device      "/dev/mouse"

# When using XQUEUE, comment out the above two lines, and uncomment
# the following line.

#    Protocol "Xqueue"

# Baudrate and SampleRate are only for some Logitech mice

#    BaudRate 9600
#    SampleRate 150

# Emulate3Buttons is an option for 2-button Microsoft mice
# Emulate3Timeout is the timeout in milliseconds (default is 50ms)

    Emulate3Buttons
    Emulate3Timeout    50

# ChordMiddle is an option for some 3-button Logitech mice

#    ChordMiddle

EndSection

The Protocol configuration item specifies the protocol used by the pointing device. Most modern PC mice, including recent Logitech mice, use the Microsoft protocol. However, other protocols are supported, including:

To learn more about mouse protocols supported by X, view the file /usr/X11R6/lib/X11/doc/README.mouse, which is part of the XFree86-doc package.

The Device configuration item simply specifies the device file associated with the pointing device.

If you have a two-button mouse, you should generally specify the Emulate3Buttons configuration item, which lets you simulate pressing a middle mouse button by simultaneously pressing the left and right mouse buttons.

The Monitor section contains several important configuration items. Several Monitor sections can be present, one for each of several monitors. Here’s an example configuration:

Section "Monitor"

    Identifier  "ViewSonic 17GS"
    VendorName  "Unknown"
    ModelName   "Unknown"

# HorizSync is in kHz unless units are specified.
# HorizSync may be a comma separated list of discrete values, or a
# comma separated list of ranges of values.
# NOTE: THE VALUES HERE ARE EXAMPLES ONLY. REFER TO YOUR MONITOR'S
# USER MANUAL FOR THE CORRECT NUMBERS.

    HorizSync   30-69

# VertRefresh is in Hz unless units are specified.
# VertRefresh may be a comma separated list of discrete values, or a
# comma separated list of ranges of values.
# NOTE: THE VALUES HERE ARE EXAMPLES ONLY. REFER TO YOUR MONITOR'S
# USER MANUAL FOR THE CORRECT NUMBERS.

    VertRefresh 50-160

# Modes can be specified in two formats. A compact one-line format, or
# a multi-line format.

# These two are equivalent

#    ModeLine "1024x768i" 45 1024 1048 1208 1264 768 776 784 817 Interlace

#    Mode "1024x768i"
#        DotClock    45
#        HTimings    1024 1048 1208 1264
#        VTimings    768 776 784 817
#        Flags        "Interlace"
#    EndMode

# This is a set of standard mode timings. Modes that are out of monitor spec
# are automatically deleted by the server (provided the HorizSync and
# VertRefresh lines are correct), so there's no immediate need to
# delete mode timings (unless particular mode timings don't work on your
# monitor). With these modes, the best standard mode that your monitor
# and video card can support for a given resolution is automatically
# used.

<lines omitted>

# 800x600 @ 100 Hz, 64.02 kHz hsync
Modeline  "800x600"    69.65  800  864  928 1088   600  604  610  640 -HSync -VSync
# 800x600 @ 56 Hz, 35.15 kHz hsync
ModeLine "800x600"     36     800  824  896 1024   600  601  603  625
# 800x600 @ 60 Hz, 37.8 kHz hsync
Modeline "800x600"     40     800  840  968 1056   600  601  605  628 +hsync +vsync
# 800x600 @ 72 Hz, 48.0 kHz hsync
Modeline "800x600"     50     800  856  976 1040   600  637  643  666 +hsync +vsync
# 800x600 @ 85 Hz, 55.84 kHz hsync
Modeline  "800x600"    60.75  800  864  928 1088   600  616  621  657 -HSync -VSync

<lines omitted>

EndSection

The following lines:

Identifier  "ViewSonic 17GS"
VendorName  "Unknown"
ModelName   "Unknown"

serve to identify the monitor. Only the Identifier configuration item is important; it’s used to refer to the monitor.

The following lines:

HorizSync   30-69
VertRefresh 50-160

give the horizontal and vertical sync rates for the monitor. Sometimes, Xconfiguratorwill pick a value that’s not quite right. Tweaking these values can turn a nonworking X configuration into a working one. Be sure, however, to specify only values consistent with the capabilities of your monitor; otherwise, you may damage it.

Perhaps the most important configuration item in the Monitor section is the ModeLine. Typically, there are many ModeLine entries, at least one for each video mode supported by the monitor. The example Monitor section shows only a handful of typical entries.

The format of a ModeLine entry is:

ModeLine name clock horizontal vertical options

The parameters have the following meanings:

Most monitors can use the Video Electronics Standards Association (VESA) modes that Xconfigurator includes in the configuration file it generates. If your monitor isn’t cooperative, you have several alternatives:

The Device section specifies the video adapter. Multiple device sections can be present. Here’s a typical Device section:

# Device configured by Xconfigurator:

Section "Device"
    Identifier  "Matrox Millennium"
    VendorName  "Unknown"
    BoardName   "Unknown"
    #VideoRam    4096
Option    "sw_cursor"
    # Insert Clocks lines here if appropriate.
EndSection

The Identifier configuration item assigns a name to the Screen section that contains it. The VendorName and BoardName configuration items are unimportant. The VideoRam configuration item specifies the amount of video memory installed on the device; it is generally commented out, since X can probe for the values of most configuration items in the Device section. The Option configuration item is used to specify a variety of options needed to support video adapter features.

A typical X configuration file contains multiple Screen sections. Each section specifies a combination consisting of a monitor, video adapter, and X server. Here’s a typical section:

# The Colour SVGA server

Section "Screen"
    Driver      "svga"
    Device      "Matrox Millennium"
    Monitor     "ViewSonic 17GS"
    DefaultColorDepth   16
    Subsection "Display"
        Depth       16
        Modes       "1280x1024" "1152x864" "1024x768" "800x600"
        ViewPort    0 0
    EndSubsection
    Subsection "Display"
        Depth       24
        Modes       "1152x864" "1024x768" "800x600"
        ViewPort    0 0
    EndSubsection
    Subsection "Display"
        Depth       32
        Modes       "1152x864" "1024x768" "800x600"
        ViewPort    0 0
    EndSubsection
EndSection

The Driver configuration item identifies the X server. Possible values are:

The Device and Monitor configuration items refer back to entries in the Device and Monitor sections.

The remaining configuration items specify video modes. These give the default color depth and the resolutions permissible for each video mode.