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✏️ Editing: keytab-lilo.txt

This is the documentation for the keytab-lilo.pl program.  It was
taken verbatim from the LILO-20 README file; only this header was
added.

LILO program code, documentation and auxiliary programs are
Copyright 1992-1997 Werner Almesberger.
All rights reserved.

Redistribution and use in source and binary forms of parts of or the
whole original or derived work are permitted provided that the
original work is properly attributed to the author. The name of the
author may not be used to endorse or promote products derived from
this software without specific prior written permission. This work
is provided "as is" and without any express or implied warranties.

To use a LILO keyboard table with Syslinux, specify the KBDMAP command
in syslinux.cfg, for example:

kbdmap de.ktl

============================================================================

Keyboard translation
--------------------

The PC keyboard emits so-called scan codes, which are basically key
numbers. The BIOS then translates those scan codes to the character codes
of the characters printed on the key-caps. By default, the BIOS normally
assumes that the keyboard has a US layout. Once an operating system is
loaded, this operating system can use a different mapping.

At boot time, LILO only has access to the basic services provided by the
BIOS and therefore receives the character codes for an US keyboard. It
provides a simple mechanism to re-map the character codes to what is
appropriate for the actual layout.*

*  The current mechanism isn't perfect, because it sits on top of the
    scan code to character code translation performed by the BIOS. This
    means that key combinations that don't produce any useful character on
    the US keyboard will be ignored by LILO. The advantage of this approach
    is its simplicity.

Compiling keyboard translation tables
- - - - - - - - - - - - - - - - - - -

LILO obtains layout information from the keyboard translation tables Linux
uses for the text console. They are usually stored in
/usr/lib/kbd/keytables. LILO comes with a program keytab-lilo.pl that reads
those tables and generates a table suitable for use by the map installer.
keytab-lilo.pl invokes the program loadkeys to print the tables in a format
that is easy to parse.*

*  On some systems, only root can execute loadkeys. It is then necessary
    to run keytab-lilo.pl as root too.

keytab-lilo.pl is used as follows:

keytab-lilo.pl [ -p <old_code>=<new_code> ] ...
    [<path>]<default_layout>[.<extension>] ]
     [<path>]<kbd_layout>[.<extension>] ]

-p <old_code>=<new_code>
     Specifies corrections ("patches") to the mapping obtained from the
    translation table files. E.g. if pressing the upper case "A" should
    yield an at sign, -p 65=64 would be used. The  -p  option can be
    repeated any number of times. The codes can also be given as
    hexadecimal or as octal numbers if they are prefixed with 0x or 0,
    respectively.
  <path>  The directory in which the file resides. The default path is
    /usr/lib/kbd/keytables.
  <extension>  Usually the trailing .map, which is automatically added if
    the file name doesn't contain dots.
  <default_layout>  Is the layout which specifies the translation by the
    BIOS. If none is specified, us is assumed.
  <kbd_layout>  Is the actual layout of the keyboard.

keytab-lilo.pl writes the resulting translation table as a binary string to
standard output. Such tables can be stored anywhere with any name, but the
suggested naming convention is /boot/<kbd>.ktl ("Keyboard Table for Lilo"),
where <kbd> is the name of the keyboard layout.

Example:

keytab-lilo.pl de >/boot/de.ktl

MR SKB