About the server keyboard
Every time you press a key on your keyboard
while running the X server,
the following signals are exchanged:
The X server keeps track of the mappings
of keycodes to keysyms, and mappings of keysyms to modifiers
in two tables in its memory:
hardware-dependent codes generated by keystrokes
and received by the X server
codes sent by the X server to the client indicating which
key was pressed. Keycodes by themselves do not indicate
what the keystroke means; the client must
request that information from the X server.
flags, such as ``shift'' and ``control,''
that the server sends with each keycode to the client.
The client's interpretation of the keycode may depend on the
state of the modifiers. For example, the state of the shift modifier
determines whether an alphabetic character should be lowercase or
Because the X server encodes the states
of the eight modifiers (shift, lock, control,
mod1, mod2, mod3, mod4, and mod5) in a single byte of
data, modifiers are often referred to as ``modifier bits.''
codes that specify the glyphs appearing on the keys.
The X server also maintains a list of strings that describe the
keysyms, such as ``a'', ``B'', and ``Control.''
To change the behavior of your keyboard while the X server
is running, you need only modify these two tables.
contains a list of keycodes that the X server sends,
and the keysyms and strings that correspond to them.
The order of keysyms in the keymap table determines which keysym
corresponds to the shifted or unshifted key.
contains a list of keysyms and keycodes to which
each of the eight modifiers are ``attached.''
For example, the default configuration attaches the mod1 modifier
to the Alt_L and Alt_R keysyms
and to the keycodes corresponding to the
left and right <Alt> keys.
When either <Alt> key is pressed,
or when any key mapped to the Alt_L or Alt_R
keysyms is pressed, the mod1 modifier is on.
Because many non-U.S. keyboards have more
than two symbols on each key,
the Shift modifier is supplemented by a modifier
known as the ``group modifier,'' and the keysym, Mode_Switch.
If the keymap table specifies more than two keysyms for a key,
the state of the group modifier determines whether the Shift
modifier toggles between the first and second keysyms,
which are referred to as ``group 1,'' or
between the third and fourth keysyms, which are
referred to as ``group 2.''
When you configure the X server for a non-U.S. keyboard,
xsconfig.sh (see the
manual page) maps Mode_Switch to the mod3 modifier.
Consequently, any key mapped to Mode_Switch in the keymap table
acts as the group modifier.
The X server's initial keyboard configuration is
read from a configuration file, .Xsco.cfg.
If the X server finds .Xsco.cfg in the user's
home directory, it reads that file. Otherwise, it reads the
system-wide default configuration file,
You can modify the contents of the keymap table
and modifier map while the X server
is running, but the initial mapping of scancodes and keycodes,
and of keysyms to strings, can only be modified by compiling a
new configuration file.
You create keyboard configuration files with
the xsconfig.sh script,
which allows you to create default
keyboard configurations for a variety of
character sets, languages, and keyboards.
Changing the modifier map
Configuring the keyboard for the server
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003