Typically, the X configuration file will be located in the /etc/ or /etc/X11/ directory. Based on the version of X being used, the configuration file may be:

• Xorg.conf
• XF86Config
• XF86Config-4

The X Window configuration file will typically have sections for:

• Module
• InputDevice
• Monitor
• Device
• Screen
• ServerLayout

Modules

The modules section, as the name implies, loads the modules (drivers) used by X.

[root@server1 ~]# cat /etc/X11/Xorg.conf

Section "Module"
    Load "dbe"
    Load "extmod"
    Load "record"
. . .
EndSection

InputDevice (keyboard / mouse)

[root@server1 ~]# cat /etc/X11/Xorg.conf

Section "InputDevice"
    Identifier "system-keyboard"
    MatchIsKeyboard "on"
    Option "XkbLayout" "us"
EndSection

Section "InputDevice"
    Identifier "system-mouse"
    Option "Protocol" "IMPS/2"
    Option "Device" "/dev/input/mice"
EndSection

Monitor

[root@server1 ~]# cat /etc/X11/Xorg.conf

Section "Monitor"
    Identifier "Monitor0"
    ModelName "Dell 9490"
    HorizSync 30.0 - 85.0
    VertRefresh 55.0 - 75.0
EndSection

Device

[root@server1 ~]# cat /etc/X11/Xorg.conf

Section "Device"
    Identifier "VideoCard0"
    vendorName "nVIDIA"
    BoardName "GeForce 7500"
    VideoRam 131072
EndSection

Screen

The screen section uses information from the Monitor and Device sections, so you must first have the Monitor and Device sections defined before defining the Screen section. 

[root@server1 ~]# cat /etc/X11/Xorg.conf

Section "Screen"
    Identifier "Screen0"
    Device "Videocard0"
    Monitor "Monitor0"
EndSection

ServerLayout

The ServerLayout section uses information from the Screen, Keyboard, and Mouse sections, so you must first have the Screen, Keyboard, and Mouse sections defined before defining the ServerLayout section.

[root@server1 ~]# cat /etc/X11/Xorg.conf

Section "ServerLayout"
    Identifier "My Server Layout"
    Screen "Screen0"
    InputDevice "Keyboard0"
    InputDevice "Mouse0"
EndSection