keymap - keyboard maps
/etc/keymap is the compressed mapping from keyboard scan codes to ASCII.
It is made from a keymap source file consisting of MAP_COLS columns
(MINIX assigns the value 6 to MAX_COLS, corresponding to key pressed,
key+SHIFT, key+LEFT_ALT, key+RIGHT_ALT, key+ALT+SHIFT and key+CTRL) and
NR_SCAN_CODES rows (MINIX assigns the value 0x80 to NR_SCAN_CODES,
corresponding to the number of scan codes to be provided by the
keyboard), and each element is 2 bytes in length (see u16_t in type
definitions). The low order byte corresponds to the character represented
by the scan code, and the high order byte corresponds to the special
meaning (when CAPS LOCK has effect, if it is a function key, etc.), which
is converted to binary keymap format using the genmap utility.
Types (general): <sys/types.h>
<sys/types.h> defines the u8_t and u16_t types, corresponding to 8 and 16
C(c) - Control
Maps to control code
A(c) - Alt
Sets the eight bit
CA(c) - Control-Alt
Short for A(C(c))
L(c) - Caps Lock
Adds Caps Lock effect
These macros are used in a keymap source file to help define keys. So
instead of writing 032 to put a CTRL-Z in the map you write C('Z'). The
L(c) macro is used in column 0 to tell that the Caps Lock key is active
for this key. (Caps Lock should only have effect on letters.)
<minix/keymap.h> contains a large number of definitions for special keys,
like function keys, and keys on the numeric keypad. They are:
Escape key and modifiers: EXT, CTRL, SHIFT, ALT.
Numeric keypad keys: HOME, END, UP, DOWN, LEFT, RIGHT, PGUP, PGDN, MID
(numeric '5'), PLUS, INSRT.
ALT + numpad key: AHOME, AEND, ..., AINSRT.
CTRL + numpad: CHOME, CEND, ..., CINSRT.
Lock keys: CALOCK (Caps Lock), NLOCK (Num Lock), SLOCK (Scroll Lock).
Function keys: F1, ..., F12.
ALT - function key: AF1, ..., AF12.
CTRL - function key: CF1, ..., CF12.
SHIFT - function key: SF1, ..., SF12.
ALT - SHIFT - function key: ASF1, ..., ASF12.
There is one key definition that isn't a key at all: EXTKEY. This
keycode is sent by the keyboard as an indicator that the next keycode is
special. For instance both ALT keys have the same keycode, but the right
ALT key is sent by the keyboard preceded by the EXTKEY keycode. The same
is true for the '/' key on the numeric pad versus the other '/' key on
the US keyboard. (On other keyboards this key may have a different
symbol.) The keyboard driver knows that a different key is presses if it
is preceded by EXTKEY.
Creating/changing keyboard mapping
You can create your own keyboard mapping by copying one of the existing
keymap source files (Standard Minix: kernel/keymaps/*.src, Minix-vmd:
kernel/ibm/keymaps/*.src) and modifying the desired keys. Once this has
been done, you need to recompile the genmap.c file, either by adding a
new entry to the Makefile, or by running the following commands:
cc -DKEYSRC=\"keymap.src\" genmap.c
After this, the keymap file can be generated by running:
a.out > keymap.map
The keymap can be loaded in the keyboard driver by:
It is wise to first run loadkeys on one of the maps in /usr/lib/keymaps
so that you can easily revert back to a known keymap with a few taps on
the up-arrow key and pressing return. You will otherwise have to fix the
keymap with a faulty keymap loaded into the keyboard driver, which is no
When the keymap is to your satisfaction you can copy it to /etc/keymap to
have it loaded automatically at reboot.
/etc/keymap Default keymap file
Victor A. Rodriguez - El bit Fantasma (Bit-Man@Tasa.Com.AR)