LILO - Generic Boot Loader for Linux ("LInux LOader") by Werner Almesberger
===========================================================================

   NOTE:  This document is no longer maintained.  However, it is
   still current.  Changes to LILO for versions 21.2 and later are
   documented in detail in the 'man' pages for 'lilo' and 'lilo.conf'.
   Refer to them first, then to this document.

  
Version 21-4 (release) -- John Coffman <johninsd@san.rr.com>

Minor changes suggested by Werner to show that this release is derived
from the source code to his version 21.  Added VERSION_MAJOR and 
VERSION_MINOR to replace VERSION.  The file VERSION is replaced by 
'version.h'.

The first and second stage loaders have been modified so that ONLY
'lba32' will use EDD packet calls.  'linear' will now always ask the
BIOS for the disk geometry, and then use C:H:S addressing.


Version 21-2  -- John Coffman <johninsd@san.rr.com>

This version was created to allow booting on disks larger than 8.4Gb using
the Enhanced BIOS call (int 0x13, AH=0x42) and the packet-call interface.
These calls are supported on post-1998 systems, and through software BIOS
extensions such as EZ-DRIVE(tm).  

My primary objective in making these changes to LILO, is not to break any-
thing.  Hence, the 32-bit direct addressing of sectors is supported by a
new keyword in the 'lilo.conf' file:  "lba32".  This keyword is mutually
exclusive with the keyword "linear".  On the command line, these options
are invoked with the new "-L" switch, or the old "-l" switch, respectively.

Apologies to Werner Almesberger for not communicating these changes/addi-
tions to him directly; but I have not been able to contact him by e-mail
at the address he provided in the latest 'lilo.lsm' file.  I do not want
versions of LILO to get out-of-step.

Disk sector addresses are conveyed from the Map Installer (lilo executable)
to the boot loaders, first- and second-stages through a 5 byte structure:

     sector    [1..63] plus 2 high bits of Cylinder
     cylinder  [0..1023] low eight bits in this byte
     device    [0..3] for floppies, [0x80..0x8F] for hard disks
     head      [0..254] no, the max is 254, not 255
     count     [1...] number of sectors to transfer
     
The first two bytes are normally loaded into the CX register, the second 
two
bytes into the DX register, and the last byte into the AL register.  This 
is
the call used for the C:H:S addressing scheme of the original IBM-PC BIOS.
LILO checks that the 64Kb DMA boundary is never crossed by a call, and that
the count never exceeds the sector count of one track on the disk.

When 'linear' is specified, a 24-bit, 0 based addressing scheme is 
employed.
The low 8 bits are in 'sector'; the middle 8 bits in 'cylinder'; and the 
high
8 bits are in 'head'.  To flag this as a 'linear' address, the 'device' 
byte
has bit 6 set (mask 0x40 or'ed in).  The count field is a maximum of 128,
since anything greater would cross a 64Kb DMA boundary.  It is up to the 
loader code (second stage only), to check that no track boundary is 
crossed.

The situation is more complicated with 'lba32' addressing.  It is flagged 
with
bit 5 of the 'device' byte being set (mask 0x20 or'ed in).  The 32-bit 
address
is spread over the 'sector', 'cylinder', 'head', and 'count' fields, from 
low
byte to high byte, respectively.  Whenever this full 32-bit address is
specified explicitly, the actual sector count to transfer is implied to be
one (1), and this fact is flagged in the 'device' byte by setting bit 5
(mask 0x10 or'ed in).  When a multi-sector transfer is called for, the high
8-bits of the address are NOT specified explicitly, but are assumed to be
the same as the previous transfer, the 'count' of sectors to transfer will
be in the range [2..127], and bit 5 (mask 0x10) of the 'device' byte will 
be
clear.

The first-stage loader uses single sector transfers only, so it uses a
simplified disk read routine, always assumes a sector transfer count of 1,
and always assumes that the full 32-bit address of the sector is specified
when 'lba32' mode is detected in the 'device' byte.  However, the second-
stage loader is capable of multi-sector transfers when map-compaction has
been used (-c switch, or 'compact' global option), so it uses the fully
capable read routine to load the -initrd- image, and the -kernel- image.

Both 'linear' and 'lba32' will use the Enhanced BIOS packet calls, if they
are available.  Otherwise, the disk address is converted to C:H:S, using 
the
disk geometry returned by (int 0x13, AH=8).  If cylinder overflow occurs --
i.e., cylinder > 1023, then error code '9f' is issued.

The BIOS calls used to implement large disk booting conform to the Enhanced
Disk Drive Specification, version 3.0, rev 0.8, dated March 12, 1998.  This
document is available on-line from Phoenix Technologies Ltd., at:
   
   http://www.phoenix.com/products/specs.html

Known bugs:
   The chain loader, 'os2_d.b', still will not boot OS2 4.0 from a 
secondary
   partition on my "D:" drive.  Boot Manager can, and I am still working on
   the problem.
----------------------------------------------------------------------------


Version 21

Important: The file INCOMPAT contains vital (in)compatibility information
           for this release of LILO. Read it before proceeding.

Installing boot loaders is inherently dangerous. Be sure to have some means
to boot your system from a different media if you install LILO on your hard
disk.


There is also a LaTeX version of this document in the "doc" directory.
It is much nicer to read than pure ASCII.


Installation
------------

Please read the file INCOMPAT for compatibility notes.

The installation procedure is described in the section "Normal first-time
installation". Please read "Booting basics" for the whole story.

*** QUICK INSTALLATION ***

    If you want to install LILO on your hard disk and if you don't want
    to use all its features, you can use the quick installation script.
    Read QuickInst for details.


 
 LILO is a versatile boot loader for Linux. It does not depend on a 
specific file system, can boot Linux kernel images from floppy disks and 
from hard disks and can even act as a "boot manager" for other operating 
systems.*

  *  PC/MS-DOS, DR DOS, OS/2, Windows 95, Windows NT, 386BSD, SCO UNIX, 
    Unixware, ...

One of up to sixteen different images can be selected at boot time. Various 
parameters, such as the root device, can be set independently for each 
kernel. LILO can even be used as the master boot record.

This document introduces the basics of disk organization and booting, 
continues with an overview of common boot techniques and finally describes 
installation and use of LILO in greater detail. The troubleshooting section 
at the end describes diagnostic messages and contains suggestions for most 
problems that have been observed in the past.

Please read at least the sections about installation and configuration if 
you're already using an older version of LILO. This distribution is 
accompanied by a file named INCOMPAT that describes further 
incompatibilities to older versions.

For the impatient: there is a quick-installation script to create a simple 
but quite usable installation. See section "Quick installation" for 
details.

But wait ... here are a few easy rules that will help you to avoid most 
problems people experience with LILO:

  - _Don't panic._ If something doesn't work, try to find out what is 
    wrong, try to verify your assumption and only then attempt to fix it. 
  - Read the documentation. Especially if what the system does doesn't 
    correspond to what you think it should do. 
  - Make sure you have an emergency boot disk, that you know how to use it, 
    and that it is always kept up to date. 
  - Run /sbin/lilo _whenever_ the kernel or any part of LILO, including its 
    configuration file, has changed. When in doubt, run it. You can't run 
    /sbin/lilo too many times. 
  - If performing a destructive upgrade and/or erasing your Linux 
    partitions, de-install LILO _before_ that if using it as the MBR. 
  - Don't trust setup scripts. Always verify the /etc/lilo.conf they create 
    before booting. 
  - If using a big disk, be prepared for inconveniences: you may have to 
    use the LINEAR option. 


System overview
---------------

LILO is a collection of several programs and other files:

  The map installer  is the program you run under Linux to put all files 
    belonging to LILO at the appropriate places and to record information 
    about the location of data needed at boot time. This program normally 
    resides in /sbin/lilo. It has to be run to refresh that information 
    whenever any part of the system that LILO knows about changes, e.g. 
    after installing a new kernel. 
  Various files  contain data LILO needs at boot time, e.g. the boot 
    loader. Those files normally reside in /boot. The most important files 
    are the boot loader (see below) and the map file (/boot/map), where the 
    map installer records the location of the kernel(s).* Another important 
    file is the configuration file, which is normally called /etc/lilo.conf 
  The boot loader  is the part of LILO that is loaded by the BIOS and that 
    loads kernels or the boot sectors of other operating systems. It also 
    provides a simple command-line interface to interactively select the 
    item to boot and to add boot options. 

  *  LILO does not know how to read a file system. Instead, the map 
    installer asks the kernel for the physical location of files (e.g. the 
    kernel image(s)) and records that information. This allows LILO to work 
    with most file systems that are supported by Linux.

LILO primarily accesses the following parts of the system:

  The root file system partition  is important for two reasons: first, LILO 
    sometimes has to tell the kernel where to look for it. Second, it is 
    frequently a convenient place for many other items LILO uses, such as 
    the boot sector, the /boot directory, and the kernels. 
  The boot sector  contains the first part of LILO's boot loader. It loads 
    the much larger second-stage loader. Both loaders are typically stored 
    in the file /boot/boot.b 
  The kernel  is loaded and started by the boot loader. Kernels typically 
    reside in the root directory or in /boot. 

Note that many of the files LILO needs at boot time have to be accessible 
with the BIOS. This creates certain restrictions, see section "BIOS 
restrictions".


Introduction
============

The following sections describe how PCs boot in general and what has to be 
known when booting Linux and using LILO in particular.


Disk organization
-----------------

When designing a boot concept, it is important to understand some of the 
subtleties of how PCs typically organize disks. The most simple case are 
floppy disks. They consist of a boot sector, some administrative data (FAT 
or super block, etc.) and the data area. Because that administrative data 
is irrelevant as far as booting is concerned, it is regarded as part of the 
data area for simplicity.

            +---------------------------+
            |Boot sector|               |
            |-----------+               |
            |                           |
            |         Data area         |
            |                           |
            |                           |
            +---------------------------+

The entire disk appears as one device (e.g. /dev/fd0) on Linux.

The MS-DOS boot sector has the following structure:

                    +------------------------+
              0x000 |Jump to the program code|
                    |------------------------|
              0x003 |                        |
                    |    Disk parameters     |
                    |                        |
                    |------------------------|
        0x02C/0x03E |                        |
                    |      Program code      |
                    |                        |
                    |                        |
                    |------------------------|
              0x1FE | Magic number (0xAA55)  |
                    +------------------------+

LILO uses a similar boot sector, but it does not contain the disk 
parameters part. This is no problem for Minix, Ext2 or similar file 
systems, because they don't look at the boot sector, but putting a LILO 
boot sector on an MS-DOS file system would make it inaccessible for MS-DOS.

Hard disks are organized in a more complex way than floppy disks. They 
contain several data areas called partitions. Up to four so-called primary 
partitions can exist on an MS-DOS hard disk. If more partitions are needed, 
one primary partition is used as an extended partition that contains 
several logical partitions.

The first sector of each hard disk contains a partition table, and an 
extended partition and _each_ logical partition contains a partition table 
too.

        +--------------------------------------------+
        | Partition table                  /dev/hda  |
        | +------------------------------------------|
        | | Partition 1                    /dev/hda1 |
        | |                                          |
        | |------------------------------------------|
        | | Partition 2                    /dev/hda2 |
        | |                                          |
        +--------------------------------------------+

The entire disk can be accessed as /dev/hda, /dev/hdb, /dev/sda, etc. The 
primary partitions are /dev/hda1 ... /dev/hda4.

        +--------------------------------------------+
        | Partition table                  /dev/hda  |
        | +------------------------------------------|
        | | Partition 1                    /dev/hda1 |
        | |                                          |
        | |------------------------------------------|
        | | Partition 2                    /dev/hda2 |
        | |                                          |
        | |------------------------------------------|
        | | Extended partition             /dev/hda3 |
        | | +----------------------------------------|
        | | | Extended partition table               |
        | | |----------------------------------------|
        | | | Partition 3                  /dev/hda5 |
        | | |                                        |
        | | |----------------------------------------|
        | | | Extended partition table               |
        | | |----------------------------------------|
        | | | Partition 4                  /dev/hda6 |
        | | |                                        |
        +--------------------------------------------+

This hard disk has two primary partitions and an extended partition that 
contains two logical partitions. They are accessed as /dev/hda5 ...

Note that the partition tables of logical partitions are not accessible as 
the first blocks of some devices, while the main partition table, all boot 
sectors and the partition tables of extended partitions are.

Partition tables are stored in partition boot sectors. Normally, only the 
partition boot sector of the entire disk is used as a boot sector. It is 
also frequently called the master boot record (MBR). Its structure is as 
follows:

                    +------------------------+
              0x000 |                        |
                    |      Program code      |
                    |                        |
                    |                        |
                    |------------------------|
              0x1BE |    Partition table     |
                    |                        |
                    |------------------------|
              0x1FE | Magic number (0xAA55)  |
                    +------------------------+

The LILO boot sector is designed to be usable as a partition boot sector. 
(I.e. there is room for the partition table.) Therefore, the LILO boot 
sector can be stored at the following locations:

  - boot sector of a Linux floppy disk. (/dev/fd0, ...) 
  - MBR of the first hard disk. (/dev/hda, /dev/sda, ...) 
  - boot sector of a primary Linux file system partition on the first hard 
    disk. (/dev/hda1, ...) 
  - partition boot sector of an extended partition on the first hard disk. 
    (/dev/hda1, ...)* 

  *  Most FDISK-type programs don't believe in booting from an extended 
    partition and refuse to activate it. LILO is accompanied by a simple 
    program (activate) that doesn't have this restriction. Linux fdisk also 
    supports activating extended partitions.

It _can't_ be stored at any of the following locations:

  - boot sector of a non-Linux floppy disk or primary partition. 
  - a Linux swap partition. 
  - boot sector of a logical partition in an extended partition.* 
  - on the second hard disk. (Unless for backup installations, if the 
    current first disk will be removed or disabled, or if some other boot 
    loader is used, that is capable of loading boot sectors from other 
    drives.) 

  *  LILO can be forced to put the boot sector on such a partition by using 
    the  -b  option or the BOOT variable. However, only few programs that 
    operate as master boot records support booting from a logical 
    partition.

Although LILO tries to detect attempts to put its boot sector at an invalid 
location, you should not rely on that.


Booting basics
--------------

When booting from a floppy disk, the first sector of the disk, the 
so-called boot sector, is loaded. That boot sector contains a small program 
that loads the respective operating system. MS-DOS boot sectors also 
contain a data area, where disk and file system parameters (cluster size, 
number of sectors, number of heads, etc.) are stored.

When booting from a hard disk, the very first sector of that disk, the 
so-called master boot record (MBR) is loaded. This sector contains a loader 
program and the partition table of the disk. The loader program usually 
loads the boot sector, as if the system was booting from a floppy.

Note that there is no functional difference between the MBR and the boot 
sector other than that the MBR contains the partition information but 
doesn't contain any file system-specific information (e.g. MS-DOS disk 
parameters).

The first 446 (0x1BE) bytes of the MBR are used by the loader program. They 
are followed by the partition table, with a length of 64 (0x40) bytes. The 
last two bytes contain a magic number that is sometimes used to verify that 
a given sector really is a boot sector.

There is a large number of possible boot configurations. The most common 
ones are described in the following sections.


MS-DOS alone
- - - - - -

        +-------------------------------------------------------+
        | Master Boot Record    Boot sector    Operating system |
        |-------------------------------------------------------|
        | DOS-MBR ------------> MS-DOS ------> COMMAND.COM      |
        +-------------------------------------------------------+

This is what usually happens when MS-DOS boots from a hard disk: the 
DOS-MBR determines the active partition and loads the MS-DOS boot sector. 
This boot sector loads MS-DOS and finally passes control to COMMAND.COM. 
(This is greatly simplified.)


LOADLIN
- - - -

    +------------------------------------------------------------+
    | Master Boot Record    Boot sector    Operating system      |
    |------------------------------------------------------------|
    | DOS-MBR ------------> MS-DOS ------> COMMAND.COM           |
    |                                 ---> LOADLIN ------> Linux |
    +------------------------------------------------------------+

A typical LOADLIN setup: everything happens like when booting MS-DOS, but 
in CONFIG.SYS or AUTOEXEC.BAT, LOADLIN is invoked. Typically, a program 
like BOOT.SYS is used to choose among configuration sections in CONFIG.SYS 
and AUTOEXEC.BAT. This approach has the pleasant property that no boot 
sectors have to be altered.

Please refer to the documentation accompanying the LOADLIN package for 
installation instructions and further details.


LILO started by DOS-MBR
- - - - - - - - - - - -

        +-------------------------------------------------------+
        | Master Boot Record    Boot sector    Operating system |
        |-------------------------------------------------------|
        | DOS-MBR ------------> LILO --------> Linux            |
        |                  ---> other OS                        |
        +-------------------------------------------------------+

This is a "safe" LILO setup: LILO is booted by the DOS-MBR. No other boot 
sectors have to be touched. If the other OS (or one of them, if there are 
several other operating systems being used) should be booted without using 
LILO, the other partition has to be marked "active" with fdisk or activate.

Installation: 

  - install LILO with its boot sector on the Linux partition. 
  - use fdisk or activate to make that partition active. 
  - reboot. 

Deinstallation: 

  - make a different partition active. 
  - install whatever should replace LILO and/or Linux. 


Several alternate branches
- - - - - - - - - - - - -

    +------------------------------------------------------------+
    | Master Boot Record    Boot sector    Operating system      |
    |------------------------------------------------------------|
    | DOS-MBR ------------> MS-DOS ------> COMMAND.COM           |
    |                                 ---> LOADLIN ------> Linux |
    |                  ---> LILO --------> Linux                 |
    |                                 ---> MS-DOS --- ...        |
    +------------------------------------------------------------+

An extended form of the above setup: the MBR is not changed and both 
branches can either boot Linux or MS-DOS. (LILO could also boot other 
operating systems.)


LILO started by BOOTACTV*
- - - - - - - - - - - - -

  *  Other, possibly better known boot switchers, e.g. OS/2 BootManager 
    operate in a similar way. The installation procedures typically vary.

        +-------------------------------------------------------+
        | Master Boot Record    Boot sector    Operating system |
        |-------------------------------------------------------|
        | BOOTACTV -----------> LILO --------> Linux            |
        |                  ---> other OS                        |
        +-------------------------------------------------------+

Here, the MBR is replaced by BOOTACTV (or any other interactive boot 
partition selector) and the choice between Linux and the other operating 
system(s) can be made at boot time. This approach should be used if LILO 
fails to boot the other operating system(s).*

  *  And the author would like to be notified if booting the other 
    operating system(s) doesn't work with LILO, but if it works with an 
    other boot partition selector.

Installation: 

  - boot Linux. 
  - make a backup copy of your MBR on a floppy disk, e.g.
     dd if=/dev/hda of=/fd/MBR bs=512 count=1 
  - install LILO with the boot sector on the Linux partition. 
  - install BOOTACTV as the MBR, e.g.
     dd if=bootactv.bin of=/dev/hda bs=446 count=1 
  - reboot. 

Deinstallation: 

  - boot Linux. 
  - restore the old MBR, e.g.
     dd if=/MBR of=/dev/hda bs=446 count=1
     or FDISK /MBR under MS-DOS. 

If replacing the MBR appears undesirable and if a second Linux partition 
exists (e.g. /usr, _not_ a swap partition), BOOTACTV can be merged with the 
partition table and stored as the "boot sector" of that partition. Then, 
the partition can be marked active to be booted by the DOS-MBR.

Example:

# dd if=/dev/hda of=/dev/hda3 bs=512 count=1
# dd if=bootactv.bin of=/dev/hda3 bs=446 count=1

_WARNING:_ Whenever the disk is re-partitioned, the merged boot sector on 
that "spare" Linux partition has to be updated too.


LILO alone
- - - - -

            +----------------------------------------+
            | Master Boot Record    Operating system |
            |----------------------------------------|
            | LILO ---------------> Linux            |
            |                  ---> other OS         |
            +----------------------------------------+

LILO can also take over the entire boot procedure. If installed as the MBR, 
LILO is responsible for either booting Linux or any other OS. This approach 
has the disadvantage, that the old MBR is overwritten and has to be 
restored (either from a backup copy, with FDISK /MBR on recent versions of 
MS-DOS or by overwriting it with something like BOOTACTV) if Linux should 
ever be removed from the system.

You should verify that LILO is able to boot your other operating system(s) 
before relying on this method.

Installation: 

  - boot Linux. 
  - make a backup copy of your MBR on a floppy disk, e.g.
     dd if=/dev/hda of=/fd/MBR bs=512 count=1 
  - install LILO with its boot sector as the MBR. 
  - reboot. 

Deinstallation: 

  - boot Linux. 
  - restore the old MBR, e.g.
     dd if=/fd/MBR of=/dev/hda bs=446 count=1 

If you've installed LILO as the master boot record, you have to explicitly 
specify the boot sector (configuration variable BOOT=...) when updating the 
map. Otherwise, it will try to use the boot sector of your current root 
partition, which will usually work, but it will probably leave your system 
unbootable.


Names
- - -

The following names have been used to describe boot sectors or parts of 
operating systems:

  "DOS-MBR"  is the original MS-DOS MBR. It scans the partition table for a 
    partition that is marked "active" and loads the boot sector of that 
    partition. Programs like MS-DOS' FDISK, Linux fdisk or activate 
    (accompanies LILO) can change the active marker in the partition table. 
  "MS-DOS"  denotes the MS-DOS boot sector that loads the other parts of 
    the system (IO.SYS, etc.). 
  "COMMAND.COM"  is the standard command interpreter of MS-DOS. 
  "LOADLIN"  is a program that loads a Linux kernel image from an MS-DOS 
    partition into memory and executes it. It is usually invoked from 
    CONFIG.SYS and is used in combination with a CONFIG.SYS configuration 
    switcher, like BOOT.SYS.* 
  "LILO"  can either load a Linux kernel or the boot sector of any other 
    operating system. It has a first stage boot sector that loads the 
    remaining parts of LILO from various locations.** 
  "BOOTACTV"  permits interactive selection of the partition from which the 
    boot sector should be read. If no key is pressed within a given 
    interval, the partition marked active is booted. BOOTACTV is included 
    in the pfdisk package. There are also several similar programs, like 
    PBOOT and OS-BS.*** 

  *  LOADLIN is available for anonymous FTP from
     ftp://tsx-11.mit.edu/pub/linux/dos_utils/lodlin<n>.tar.gz
     ftp://sunsite.unc.edu/pub/Linux/system/boot/dualboot/lodlin<n>.tgz
     BOOT.SYS is available for anonymous FTP from
     ftp://ftp.funet.fi/pub/Linux/tools/boot142.zip

  **  LILO can be found in
     ftp://tsx-11.mit.edu/pub/linux/packages/lilo/lilo-<n>.tar.gz
     ftp://sunsite.unc.edu/pub/Linux/system/boot/lilo/lilo-<n>.tar.gz
     ftp://lrcftp.epfl.ch/pub/linux/local/lilo/lilo-<n>.tar.gz

  ***  pfdisk is available for anonymous FTP from
     ftp://sunsite.unc.edu/pub/Linux/utils/disk-management/pfdisk.tar.Z or
     ftp://ftp.funet.fi/pub/Linux/tools/pfdisk.tar.Z
     PBOOT can be found in
     ftp://ftp.funet.fi/pub/Linux/tools/pboot.zip


Choosing the "right" boot concept
-----------------------------------

Although LILO can be installed in many different ways, the choice is 
usually limited by the present setup and therefore, typically only a small 
number of configurations which fit naturally into an existing system 
remains. The following sections describe various possible cases. See also 
section "BIOS restrictions".

The configuration file /etc/lilo.conf for the examples could look like 
this:

boot = /dev/hda2
compact
image = /vmlinuz
image = /vmlinuz.old
other = /dev/hda1
  table = /dev/hda
  label = msdos

It installs a Linux kernel image (/vmlinuz), an alternate Linux kernel 
image (/vmlinuz.old) and a chain loader to boot MS-DOS from /dev/hda1. The 
option COMPACT on the second line instructs the map installer to optimize 
loading.

In all examples, the names of the IDE-type hard disk devices (/dev/hda...) 
are used. Everything applies to other disk types (e.g. SCSI disks; 
/dev/sda...) too.


BIOS restrictions
- - - - - - - - -

Nowadays, an increasing number of systems is equipped with comparably large 
disks or even with multiple disks. At the time the disk interface of the 
standard PC BIOS has been designed (about 16 years ago), such 
configurations were apparently considered to be too unlikely to be worth 
supporting.

The most common BIOS restrictions that affect LILO are the limitation to 
two hard disks and the inability to access more than 1024 cylinders per 
disk. LILO can detect both conditions, but in order to work around the 
underlying problems, manual intervention is necessary.

The drive limit does not exist in every BIOS. Some modern motherboards and 
disk controllers are equipped with a BIOS that supports more (typically 
four) disk drives. When attempting to access the third, fourth, etc. drive, 
LILO prints a warning message but continues. Unless the BIOS really 
supports more than two drives, the system will _not_ be able to boot in 
that case.*

  *  However, if only "unimportant" parts of the system are located on the 
    "high" drives, some functionality may be available.

The cylinder limit is a very common problem with IDE disks. There, the 
number of cylinders may already exceed 1024 if the drive has a capacity of 
more than 504 MB. Many SCSI driver BIOSes present the disk geometry in a 
way that makes the limit occur near 1 GB. Modern disk controllers may even 
push the limit up to about 8 GB. All cylinders beyond the 1024th are 
inaccessible for the BIOS. LILO detects this problem and aborts the 
installation (unless the LINEAR option is used, see section "Global 
options").

Note that large partitions that only partially extend into the "forbidden 
zone" are still in jeopardy even if they appear to work at first, because 
the file system does not know about the restrictions and may allocate disk 
space from the area beyond the 1024th cylinder when installing new kernels. 
LILO therefore prints a warning message but continues as long as no 
imminent danger exists.

There are four approaches of how such problems can be solved: 

  - use of a different partition which is on an accessible disk and which 
    does not exceed the 1024 cylinder limit. If there is only a DOS 
    partition which fulfills all the criteria, that partition can be used 
    to store the relevant files. (See section "/boot on a DOS partition".) 
  - rearranging partitions and disks. This is typically a destructive 
    operation, so extra care should be taken to make good backups. 
  - if the system is running DOS or Windows 95, LOADLIN can be used instead 
    of LILO. 
  - if all else fails, installation of a more capable BIOS, a different 
    controller or a different disk configuration. 

LILO depends on the BIOS to load the following items: 

  - /boot/boot.b 
  - /boot/map (created when running /sbin/lilo) 
  - all kernels 
  - the boot sectors of all other operating systems it boots 
  - the startup message, if one has been defined 

Normally, this implies that the Linux root file system should be in the 
"safe" area. However, it is already sufficient to put all kernels into 
/boot and to either mount a "good" partition on /boot or to let /boot be a 
symbolic link pointing to or into such a partition.

See also /usr/src/linux/Documentation/ide.txt (or 
/usr/src/linux/drivers/block/README.ide in older kernels) for a detailed 
description of problems with large disks.


One disk, Linux on a primary partition
- - - - - - - - - - - - - - - - - - -

If at least one primary partition of the first hard disk is used as a Linux 
file system (/, /usr, etc. but _not_ as a swap partition), the LILO boot 
sector should be stored on that partition and it should be booted by the 
original master boot record or by a program like BOOTACTV.

            +--------------------------+
            | MBR            /dev/hda  |
            | +------------------------|
            | | MS-DOS       /dev/hda1 |
            | |------------------------|
        --> | | Linux /      /dev/hda2 |
            +--------------------------+

In this example, the BOOT variable could be omitted, because the boot 
sector is on the root partition.


One disk, Linux on a logical partition
- - - - - - - - - - - - - - - - - - -

If no primary partition is available for Linux, but at least one logical 
partition of an extended partition on the first hard disk contains a Linux 
file system, the LILO boot sector should be stored in the partition sector 
of the extended partition and it should be booted by the original master 
boot record or by a program like BOOTACTV.

            +--------------------------+
            | MBR            /dev/hda  |
            | +------------------------|
            | | MS-DOS       /dev/hda1 |
            | |------------------------|
        --> | | Extended     /dev/hda2 |
            | | +----------------------|
            | | | Linux      /dev/hda5 |
            | | |----------------------|
            | | | ...        /dev/hda6 |
            +--------------------------+

Because many disk partitioning programs refuse to make an extended 
partition (in our example /dev/hda2) active, you might have to use 
activate, which comes with the LILO distribution.

OS/2 BootManager should be able to boot LILO boot sectors from logical 
partitions. The installation on the extended partition itself is not 
necessary in this case.


Two disks, Linux (at least partially) on the first disk
- - - - - - - - - - - - - - - - - - - - - - - - - - - -

This case is equivalent to the configurations where only one disk is in the 
system. The Linux boot sector resides on the first hard disk and the second 
disk is used later in the boot process.

Only the location of the boot sector matters - everything else 
(/boot/boot.b, /boot/map, the root file system, a swap partition, other 
Linux file systems, etc.) can be located anywhere on the second disk, 
provided that the constraints described in section "BIOS restrictions" are 
met.


Two disks, Linux on second disk, first disk has an extended partition
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

If there is no Linux partition on the first disk, but there is an extended 
partition, the LILO boot sector can be stored in the partition sector of 
the extended partition and it should be booted by the original master boot 
record or by a program like BOOTACTV.

                 FIRST DISK                     SECOND DISK
        +--------------------------+    +--------------------------+
        | MBR            /dev/hda  |    | MBR            /dev/hdb  |
        | +------------------------|    | +------------------------|
        | | MS-DOS       /dev/hda1 |    | | Linux        /dev/hdb1 |
        | |------------------------|    | |------------------------|
    --> | | Extended     /dev/hda2 |    | | ...          /dev/hdb2 |
        | | +----------------------|    | |                        |
        | | | ...        /dev/hda5 |    | |                        |
        | | |----------------------|    | |                        |
        | | | ...        /dev/hda6 |    | |                        |
        +--------------------------+    +--------------------------+

The program activate, that accompanies LILO, may have to be used to set the 
active marker on an extended partition, because MS-DOS' FDISK and some 
older version of Linux fdisk refuse to do that. (Which is generally a good 
idea.)


Two disks, Linux on second disk, first disk has no extended partition
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

If there is neither a Linux partition nor an extended partition on the 
first disk, then there's only one place left, where a LILO boot sector 
could be stored: the master boot record.

In this configuration, LILO is responsible for booting all other operating 
systems too.

                 FIRST DISK                     SECOND DISK
        +--------------------------+    +--------------------------+
    --> | MBR            /dev/hda  |    | MBR            /dev/hdb  |
        | +------------------------|    | +------------------------|
        | | MS-DOS       /dev/hda1 |    | | Linux        /dev/hdb1 |
        | |------------------------|    | |------------------------|
        | | ...          /dev/hda2 |    | | ...          /dev/hdb2 |
        +--------------------------+    +--------------------------+

You should back up your old MBR before installing LILO and verify that LILO 
is able to boot your other operating system(s) before relying on this 
approach.

The line boot = /dev/hda2 in /etc/lilo.conf would have to be changed to 
boot = /dev/hda in this example.


More than two disks
- - - - - - - - - -

On systems with more than two disks, typically only the first two can be 
accessed. The configuration choices are therefore the same as with two 
disks.

When attempting to access one of the extra disks, LILO displays a warning 
message ( Warning: BIOS drive 0x<number> may not be accessible ) but does 
not abort. This is done in order to allow the lucky few whose BIOS (or 
controller-BIOS) does support more than two drives to make use of this 
feature. By all others, this warning should be considered a fatal error.

Note that the two disks restriction is only imposed by the BIOS. Linux 
normally has no problems using all disks once it is booted.


/boot on a DOS partition
- - - - - - - - - - - -

Recent kernels support all the functions LILO needs to map files also on 
MS-DOS (or UMSDOS) file systems. Since DOS partitions tend to occupy 
exactly the places where BIOS restrictions (see section "BIOS 
restrictions") are invisible, they're an ideal location for /boot if the 
native Linux file systems can't be used because of BIOS problems.

In order to accomplish this, the DOS partition is mounted read-write, a 
directory (e.g. /dos/linux) is created, all files from /boot are moved to 
that directory, /boot is replaced by a symbolic link to it, the kernels are 
also moved to the new directory, their new location is recorded in 
/etc/lilo.conf, and finally /sbin/lilo is run.

From then on, new kernels must always be copied into that directory on the 
DOS partition before running /sbin/lilo, e.g. when recompiling a kernel, 
the standard procedure changes from

# make zlilo

to

# make zImage
# mv /dos/linux/vmlinuz /dos/linux/vmlinuz.old
# mv arch/i386/boot/zImage /dos/linux/vmlinuz
# /sbin/lilo

_WARNING:_ De-fragmenting such a DOS partition is likely to make Linux or 
even the whole system unbootable. Therefore, the DOS partition should 
either not be de-fragmented, or a Linux boot disk should be prepared (and 
tested) to bring up Linux and to run /sbin/lilo after the 
de-fragmentation.*

  *  Setting the "system" attribute from DOS on the critical files (e.g. 
    everything in C:\LINUX) may help to protect them from being rearranged. 
    However, the boot floppy should still be ready, just in case.


The boot prompt
===============

Immediately after it's loaded, LILO checks whether one of the following is 
happening:

  - any of the [Shift], [Control] or [Alt] keys is pressed. 
  - [CapsLock] or [ScrollLock] is set. 

If this is the case, LILO displays the boot: prompt and waits for the name 
of a boot image (i.e. Linux kernel or other operating system). Otherwise, 
it boots the default boot image* or - if a delay has been specified - waits 
for one of the listed activities until that amount of time has passed.

  *  The default boot image is either the first boot image, the image 
    specified with the DEFAULT variable, or the image that has been 
    selected at the boot prompt.

At the boot prompt, the name of the image to boot can be entered. Typing 
errors can be corrected with [BackSpace], [Delete], [Ctrl U] and [Ctrl X]. 
A list of known images can be obtained by pressing [?] or [Tab].

If [Enter] is pressed and no file name has been entered, the default image 
is booted.


Boot command-line options
-------------------------

LILO is also able to pass command-line options to the kernel. Command-line 
options are words that follow the name of the boot image and that are 
separated by spaces.

Example:

boot: linux single root=200

This document only gives an overview of boot options. Please consult Paul 
Gortmaker's BootPrompt-HOWTO for a more complete and more up to date list. 
You can get it from 
ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/BootPrompt-HOWTO.gz or from one 
of the many mirror sites.


Standard options
- - - - - - - -

Recent kernels recognize a large number of options, among them are  debug ,  
no387 ,  no-hlt ,  ramdisk=<size> ,  reserve=<base>,<size>,... ,  
root=<device> ,  ro , and  rw . All current init programs also recognize 
the option  single . The options  lock  and  vga  are processed by the boot 
loader itself. Boot command-line options are always case-sensitive.

 single  boots the system in single-user mode. This bypasses most system 
initialization procedures and directly starts a root shell on the console. 
Multi-user mode can typically be entered by exiting the single-user shell 
or by rebooting.

 root=<device>  changes the root device. This overrides settings that may 
have been made in the boot image and on the LILO command line. <device> is 
either the hexadecimal device number or the full path name of the device, 
e.g. /dev/hda3.*

  *  The device names are hard-coded in the kernel. Therefore, only the 
    "standard" names are supported and some less common devices may not be 
    recognized. In those cases, only numbers can be used.

 reserve=<base>,<size>,...  reserves IO port regions. This can be used to 
prevent device drivers from auto-probing addresses where other devices are 
located, which get confused by the probing.

 ro  instructs the kernel to mount the root file system read-only.  rw  
mounts it read-write. If neither  ro  nor  rw  is specified, the setting 
from the boot image is used.

 no-hlt  avoids executing a  HLT  instructions whenever the system is idle.  
HLT  normally significantly reduces power consumption and therefore also 
heat dissipation of the CPU, but may not work properly with some clone 
CPUs.  no387  disables using the hardware FPU even if one is present.

 debug  enables more verbose console logging.

Recent kernels also accept the options  init=<name>  and  noinitrd .  init  
specifies the name of the init program to execute. Therefore, if single 
mode cannot be entered because init is mis-configured, one may still be 
able to reach a shell using init=/bin/sh.  noinitrd  disables automatic 
loading of the initial RAM disk. Instead, its content is then available on 
/dev/initrd.

 vga=<mode>  alters the VGA mode set at startup. The values  normal ,  
extended ,  ask  or a decimal number are recognized. (See also "Booting 
kernel images from a file".)

 kbd=<code>,...  preloads a sequence of keystrokes in the BIOS keyboard 
buffer. The keystrokes have to be entered as 16 bit hexadecimal numbers, 
with the upper byte containing the scan code and the lower byte containing 
the ASCII code. Note that most programs only use the ASCII code, so the 
scan code can frequently be omitted. Scan code tables can be found in many 
books on PC hardware. Note that scan codes depend on the keyboard layout.

Finally,  lock  stores the current command-line as the default 
command-line, so that LILO boots the same image with the same options 
(including  lock ) when invoked the next time.


Device-specific options
- - - - - - - - - - - -

There is also a plethora of options to specify certain characteristics 
(e.g. IO and memory addresses) of devices. Some common ones are  ether ,  
floppy ,  hd ,  bmouse , and  sound . The usage of these options is  
<option>=<number>,... . Please consult the corresponding FAQs and HOWTOs 
for details. For an overview of all available options, consult the file 
init/main.c in the kernel source tree.


Other options
- - - - - - -

Options of the type  <variable>=<value>  which are neither standard options 
nor device-specific options, cause the respective variables to be set in 
the environment passed to init. The case of the variable name is preserved, 
i.e. it isn't automatically converted to upper case.

Note that environment variables passed to init are typically available in 
system initialization scripts (e.g. /etc/rc.local), but they're not visible 
from ordinary login sessions, because the login program removes them from 
the user's environment.


Repeating options
- - - - - - - - -

The effect of repeating boot command-line options depends on the options.* 
There are three possible behaviours:

  *  Options are frequently repeated when a string defined with APPEND or 
    LITERAL is prepended to the parameters typed in by the user. Also, LILO 
    implicitly prepends the options  ramdisk ,  ro ,  root , or  rw  when 
    RAMDISK, READ-ONLY, READ-WRITE, or ROOT, respectively, are set in the 
    configuration file. ( lock  and  vga  are handled by a different 
    internal mechanism.)

Options that only enable or disable a certain functionality can be repeated 
any number of times.  debug ,  lock ,  no-hlt , and  no387  fall into this 
category.

Other options change a global setting whenever they appear, so only the 
value or presence of the last option matters. The antagonists  ro  and  rw  
are such options. Also,  ramdisk ,  root , and  vga  work this way. 
Example:  ro rw  would mount the root file system read-write.

Finally, when  reserve  and many device-specific options are repeated, each 
occurrence has its own meaning, e.g.  hd=... hd=...  would configure two 
hard disks, and  reserve=0x300,8 reserve=0x5f0,16  would reserve the ranges 
0x300 to 0x307 and 0x5f0 to 0x5ff (which is equivalent to writing  
reserve=0x300,8,0x5f0,16 ).


Implicit options
- - - - - - - -

LILO always passes the string  BOOT_IMAGE=<name>  to the kernel, where 
<name> is the name by which the kernel is identified (e.g. the label). This 
variable can be used in /etc/rc to select a different behaviour, depending 
on the kernel.

When booting automatically, i.e. without human intervention, the word  auto  
is also passed on the command line. This can be used by init to suppress 
interactive prompts in the boot phase.


Boot image selection
--------------------

The details of selecting the boot image are somewhat complicated. The 
following tables illustrate them. First, if neither PROMPT is set nor a 
shift key is being pressed:

Externally  Command   |  Auto-  Booted image             
 provided   line in   |  matic                           
cmd. line* map file** | boot***                          
---------------------------------------------------------
    No         No     |   Yes   Default image            
   Yes         -      |   Yes   Specified by external    
                      |         command line             
    No        Yes     |   Yes   Specified by command line
                      |         in map file              
       

  *  Externally provided command lines could be used to add front-ends to 
    LILO. They would pass the respective command string to LILO, which 
    would then interpret it like keyboard input. This feature is currently 
    not used.

  **  This command line is set by invoking the map installer with the  -R  
    option, by using the boot command-line option  lock , or if a fallback 
    command line is set (with FALLBACK).

  ***  I.e. the keyword  auto  is added.

If PROMPT is not set and a shift key is being pressed:

 Input  Empty  Extern. Cmd.l. | Auto- Booted image         
timeout cmd.l. cmd.l.  in map | matic                      
                        file  | boot                       
-----------------------------------------------------------
  No      No      -      -    |  No   Specified by the user
  No     Yes      -      -    |  No   Default image        
  Yes    n/a      -      -    |  Yes  Default image        

Finally, if the configuration variable PROMPT is set:

 Input  Empty  Extern. Cmd.l. | Auto- Booted image         
timeout cmd.l. cmd.l.  in map | matic                      
                        file  | boot                       
-----------------------------------------------------------
  No      No     No      No   |  No   Specified by the user
  No     Yes     No      No   |  No   Default image        
  Yes    n/a     No      No   |  Yes  Default image        
  n/a    n/a     Yes     -    |  Yes  Specified by external
                              |       command line         
  n/a    n/a     No     Yes   |  Yes  Specified by command 
                              |       line in map file     

Note that LILO pauses for the amount of time specified in DELAY when at the 
end of a default command line. The automatic boot can then be interrupted 
by pressing a modifier key ([Shift], [Ctrl], etc.).

The default image is the first image in the map file or the image specified 
with the DEFAULT variable. However, after an unsuccessful boot attempt, the 
respective image becomes the default image.


Map installer
=============

The map installer program /sbin/lilo updates the boot sector and creates 
the map file. If the map installer detects an error, it terminates 
immediately and does not touch the boot sector and the map file.

Whenever the map installer updates a boot sector, the original boot sector 
is copied to /boot/boot.<number>, where <number> is the hexadecimal device 
number. If such a file already exists, no backup copy is made. Similarly, a 
file  /boot/part.<number>  is created if LILO modifies the partition table. 
(See "General per-image options".)


Command-line options
--------------------

The LILO map installer can be invoked in the following ways:


Show current installation
- - - - - - - - - - - - -

The currently mapped files are listed. With  -v , also many parameters are 
shown.

  /sbin/lilo [ -C <config_file> ] -q [ -m <map_file> ] [ -v ... ]  

   -C <config_file>    
     Specifies the configuration file that is used by the map installer 
    (see section "Configuration"). If  -C  is omitted, /etc/lilo.conf is 
    used. 
   -m <map_file>    
     Specifies an alternate map file. See also sections "Options 
    corresponding to configuration variables" and "Global options". 
   -q    
     Lists the currently mapped files. 
   -v ...    
     Increase verbosity. See also sections "Options corresponding to 
    configuration variables" and "Global options". 


Create or update map
- - - - - - - - - -

A new map is created for the images described in the configuration file 
/etc/lilo.conf and they are registered in the boot sector.

  /sbin/lilo [ -C <config_file> ] [ -b <boot_device> ] [ -c ] [ -l ] [ -i 
    <boot_sector> ] [ -f <disk_tab> ] [ -m <map_file> ] [ -d <delay> ] [ -v 
    ... ] [ -t ] [ -s <save_file> | -S <save_file> ] [ -P fix | -P ignore ] 
    [ -r <root_dir> ]  

   -b <boot_device>    
     Specifies the boot device. See also sections "Options corresponding to 
    configuration variables" and "Global options". 
   -c    
     Enables map compaction. See also sections "Options corresponding to 
    configuration variables" and "Global options". 
   -C <config_file>    
     Specifies an alternate configuration file. See also section "Show 
    current installation". 
   -d <delay>    
     Sets the delay before LILO boots the default image. Note that the 
    delay is specified in _tenths_ of a second. See also sections "Options 
    corresponding to configuration variables" and "Global options". 
   -D <name>    
     Specifies the default image. See also sections "Options corresponding 
    to configuration variables" and "Global options". 
   -f <disk_tab>    
     Specifies a disk parameter table file. See also sections "Options 
    corresponding to configuration variables" and "Global options". 
   -i <boot_sector>    
     Specifies an alternate boot file. See also sections "Options 
    corresponding to configuration variables" and "Global options". 
   -L    
     Enables lba32 sector addresses. See also sections "Options 
    corresponding to configuration variables" and "Global options". 
   -l    
     Enables linear sector addresses. See also sections "Options 
    corresponding to configuration variables" and "Global options". 
   -m <map_file>    
     Specifies an alternate map file. See also sections "Options 
    corresponding to configuration variables" and "Global options". 
   -P <mode>    
     Specifies how invalid partition table entries should be handled. See 
    also sections "Options corresponding to configuration variables" and 
    "Global options". 
   -r <root_directory>    
     Chroots to the specified directory before doing anything else. This is 
    useful when running the map installer while the normal root file system 
    is mounted somewhere else, e.g. when recovering from an installation 
    failure with a recovery disk. The  -r  option is implied if the 
    environment variable  ROOT  is set.* The current directory is changed 
    to the new root directory, so using relative paths may not work. 
   -s <save_file>    
     Specifies an alternate boot sector save file. See also sections 
    "Options corresponding to configuration variables" and "Global 
    options". 
   -S <save_file>    
     Like  -s , but overwrites old save files. 
   -t    
     Test only. This performs the entire installation procedure except 
    replacing the map file, writing the modified boot sector and fixing 
    partition tables. This can be used in conjunction with the  -v  option 
    to verify that LILO will use sane values. 
   -v ...    
     Increase verbosity. See also sections "Options corresponding to 
    configuration variables" and "Global options". 

  *  E.g. if your root partition is mounted on /mnt, you can update the map 
    by simply running  ROOT=/mnt /mnt/sbin/lilo 


Change default command line
- - - - - - - - - - - - - -

Changes LILO's default command line. See also section "Boot image 
selection".

  /sbin/lilo [ -C <config_file> ] [ -m <map_file> ] -R [ <word> ... ]  

   -C <config_file>    
     Specifies an alternate configuration file. See also section "Show 
    current installation". 
   -m <map_file>    
     Specifies an alternate map file. See also sections "Options 
    corresponding to configuration variables" and "Global options". 
   -R <word ...>    
     Stores the specified words in the map file. The boot loader uses those 
    words as the default command line when booting the next time. That 
    command line is removed from the map file by the boot loader by 
    overwriting the sector immediately after reading it. The first word has 
    to be the name of a boot image. If  -R  is not followed by any words, 
    the current default command line in the map file is erased.* If the 
    command line isn't valid, the map installer issues an error message and 
    returns a non-zero exit code. 

  *   -R  is typically used in reboot scripts, e.g.
     #!/bin/sh
     cd /
     /sbin/lilo -R "$*" && reboot


Kernel name translation
- - - - - - - - - - - -

Determines the path of the kernel.

  /sbin/lilo [ -C <config_file> ] -I <name> [ <options> ]  

   -C <config_file>    
     Specifies an alternate configuration file. See also section "Show 
    current installation". 
   -I <name> [ <options> ]    
     Translates the specified label name to the path of the corresponding 
    kernel image and prints that path on standard output. This can be used 
    to synchronize files that depend on the kernel (e.g. the ps database). 
    The image name can be obtained from the environment variable  
    BOOT_IMAGE . An error message is issued and a non-zero exit code is 
    returned if no matching label name can be found. The existence of the 
    image file is verified if the option character  v  is added. 


De-installation
- - - - - - - -

Restores the boot sector that was used before the installation of LILO. 
Note that this option only works properly if LILO's directories (e.g. 
/boot) have not been touched since the first installation. See also section 
"LILO de-installation".

  /sbin/lilo [ -C <config_file> ] [ -s <save_file> ] -u | -U [ 
    <boot_device> ]  

   -C <config_file>    
     Specifies an alternate configuration file. See also section "Show 
    current installation". 
   -s <save_file>    
     Specifies an alternate boot sector save file. See also sections 
    "Options corresponding to configuration variables" and "Global 
    options". 
   -u [ <device_name> ]    
     Restores the backup copy of the specified boot sector. If no device is 
    specified, the value of the boot variable is used. If this one is also 
    unavailable, LILO uses the current root device. The name of the backup 
    copy is derived from the device name. The -s option or the backup 
    variable can be used to override this. LILO validates the backup copy 
    by checking a time stamp. 
   -U [ <device_name> ]    
     Like -u, but does not check the time stamp. 


Print version number
- - - - - - - - - -

  /sbin/lilo -V  

   -V    
     Print the version number and exit. 


Options corresponding to configuration variables
- - - - - - - - - - - - - - - - - - - - - - - -

There are also many command-line options that correspond to configuration 
variables. See section "Global options" for a description.

Command-line option | Configuration variable    
------------------------------------------------
-b <boot_device>    | boot=<boot_device>        
-c                  | compact                   
-d <tsecs>          | delay=<tsecs>             
-D <name>           | default=<name>            
-i <boot_sector>    | install=<boot_sector>     
-L                  | lba32                     
-l                  | linear                    
-m <map_file>       | map=<map_file>            
-P fix              | fix-table                 
-P ignore           | ignore-table              
-s <backup_file>    | backup=<backup_file>      
-S <backup_file>    | force-backup=<backup_file>
-v ...              | verbose=<level>           


Configuration
-------------

The configuration information is stored in the file /etc/lilo.conf and 
consists of variable assignments.


Syntax
- - -

The following syntax rules apply:

  - flag variables consist of a single word and are followed by whitespace 
    or the end of the file. 
  - string variables consist of the variable name, optional whitespace, an 
    equal sign, optional whitespace, the value and required whitespace, or 
    the end of the file. 
  - a non-empty sequence of blanks, tabs, newlines and comments counts as 
    whitespace. 
  - variable names are case-insensitive. Values are usually case-sensitive, 
    but there are a few exceptions. (See below.) 
  - tabs and newlines are special characters and may not be part of a 
    variable name or a value. The use of other control characters and 
    non-ASCII characters is discouraged. 
  - blanks and equal signs may only be part of a variable name or a value 
    if they are escaped by a backslash or if the value is embedded in 
    double quotes. An equal sign may not be the only character in a name or 
    value. 
  - an escaped tab is converted to an escaped blank. An escaped newline is 
    removed from the input stream. An escaped backslash (i.e. two 
    backslashes) is converted to a backslash. Inside quoted strings, only 
    double quotes, backslashes, dollar signs, and newlines can be escaped. 
  - quoted strings can be continued over several lines by ending each 
    incomplete line with a backslash. A single space is inserted in the 
    string for the line end and all spaces or tabs that follow immediately 
    on the next line. 
  - environment variables can be used by specifying them in the form 
    $<name> or ${<name>}. Dollar signs can be escaped. 
  - comments begin with a number sign and end with the next newline. All 
    characters (including backslashes) until the newline are ignored. 

Example:

boot = $FD
install = $MNT/boot.b
map = $MNT/map
compact
read-only
append = "nfsroot=/home/linux-install/root \
  nfsaddrs=128.178.156.28:128.178.156.24::255.255.255.0:lrcinst"
image = $MNT/zImage


Global options
- - - - - - -

/etc/lilo.conf begins with a possibly empty global options section. Many 
global options can also be set from the command line, but storing permanent 
options in the configuration file is more convenient.

The following global options are recognized:

  BACKUP=<backup_file>  Copy the original boot sector to <backup_file> 
    (which may also be a device, e.g. /dev/null) instead of 
    /boot/boot.<number> 
  BOOT=<boot_device>  Sets the name of the device (e.g. a hard disk 
    partition) that contains the boot sector. If BOOT is omitted, the boot 
    sector is read from (and possibly written to) the device that is 
    currently mounted as root. 
  CHANGE-RULES  Defines partition type numbers. See section "Partition type 
    change rules" for details. 
  COMPACT  Tries to merge read requests for adjacent sectors into a single 
    read request. This drastically reduces load time and keeps the map 
    smaller. Using COMPACT is especially recommended when booting from a 
    floppy disk. COMPACT may conflict with LINEAR or LBA32, see section 
    "Other problems". 
  DEFAULT=<name>  Uses the specified image as the default boot image. If 
    DEFAULT is omitted, the image appearing first in the configuration file 
    is used. 
  DELAY=<tsecs>  Specifies the number of _tenths_ of a second LILO should 
    wait before booting the first image. This is useful on systems that 
    immediately boot from the hard disk after enabling the keyboard. LILO 
    doesn't wait if DELAY is omitted or if DELAY is set to zero. 
  DISK=<device_name>  Defines non-standard parameters for the specified 
    disk. See section "Disk geometry" for details. 
  FIX-TABLE  Allows LILO to adjust 3D addresses in partition tables. Each 
    partition entry contains a 3D (sector/head/cylinder) and a linear 
    32-bit address of the first and the last sector of the partition. If a 
    partition is not track-aligned and if certain other operating systems 
    (e.g. PC/MS-DOS or OS/2) are using the same disk, they may change the 
    3D address. LILO can store its boot sector only on partitions where 
    both address types correspond. LILO re-adjusts incorrect 3D start 
    addresses if FIX-TABLE is set.

     _WARNING:_ This does not guarantee that other operating systems may 
    not attempt to reset the address later. It is also possible that this 
    change has other, unexpected side-effects. The correct fix is to 
    re-partition the drive with a program that does align partitions to 
    tracks. Also, with some disks (e.g. some large EIDE disks with address 
    translation enabled), under some circumstances, it may even be 
    unavoidable to have conflicting partition table entries. 
  FORCE-BACKUP=<backup_file>  Like BACKUP, but overwrite an old backup copy 
    if it exists. BACKUP=<backup_file> is ignored if FORCE-BACKUP appears 
    in the same configuration file. 
  IGNORE-TABLE  Tells LILO to ignore corrupt partition tables and to put 
    the boot sector even on partitions that appear to be unsuitable for 
    that. 
  INSTALL=<boot_sector>  Install the specified file as the new boot sector. 
    If INSTALL is omitted, /boot/boot.b is used as the default. 
  KEYTABLE=<table_file>  Re-map the keyboard as specified in this file. See 
    section "Keyboard translation" for details. 
  LBA32  Generate 32-bit Logical Block Addresses instead of 
    sector/head/cylinder addresses. If the BIOS supports packet addressing, 
    then packet calls will be used to access the disk. This allows booting 
    from any partition on disks with more than 1024 cylinders. If the BIOS 
    does not support packet addressing, then LBA32 addresses are translated 
    to C:H:S, just as for LINEAR. All floppy disk references are retained 
    in C:H:S form. Use of LBA32 is recommended on all post-1998 systems. 
    LBA32 may conflict with COMPACT, see section "Other problems". 
  LINEAR  Generate linear sector addresses instead of sector/head/cylinder 
    addresses. Linear addresses are translated at run time and do not 
    depend on disk geometry. Note that boot disks may not be portable if 
    LINEAR is used, because the BIOS service to determine the disk geometry 
    does not work reliably for floppy disks. When using LINEAR with large 
    disks, /sbin/lilo may generate references to inaccessible disk areas 
    (see section "BIOS restrictions"), because 3D sector addresses are not 
    known before boot time. LINEAR may conflict with COMPACT, see section 
    "Other problems". 
  MAP=<map_file>  Specifies the location of the map file. If MAP is 
    omitted, a file /boot/map is used. 
  MESSAGE=<message_file>  Specifies a file containing a message that is 
    displayed before the boot prompt. No message is displayed while waiting 
    for a modifier key ([Shift], etc.) after printing "LILO ". In the 
    message, the  FF  character ([Ctrl L]) clears the local screen. The 
    size of the message file is limited to 65535 bytes. The map file has to 
    be rebuilt if the message file is changed or moved. 
  NOWARN  Disables warnings about possible future dangers. 
  PROMPT  Forces entering the boot prompt without expecting any prior 
    key-presses. Unattended reboots are impossible if PROMPT is set and 
    TIMEOUT isn't. 
  SERIAL=<parameters>  Enables control from a serial line. The specified 
    serial port is initialized and LILO is accepting input from it and from 
    the PC's keyboard. Sending a break on the serial line corresponds to 
    pressing a shift key on the console in order to get LILO's attention. 
    All boot images should be password-protected if the serial access is 
    less secure than access to the console, e.g. if the line is connected 
    to a modem. The parameter string has the following syntax:
      <port>,<bps><parity><bits> 
     The components <bps>, <parity> and <bits> can be omitted. If a 
    component is omitted, all following components have to be omitted too. 
    Additionally, the comma has to be omitted if only the port number is 
    specified. 

      <port>  the number of the serial port, zero-based. 0 corresponds to 
        COM1 alias /dev/ttyS0, etc. All four ports can be used (if 
        present). 
      <bps>  the baud rate of the serial port. The following baud rates are 
        supported: 110, 300, 1200, 2400, 4800, 9600, 19200, and 38400 bps. 
        Default is 2400 bps. 
      <parity>  the parity used on the serial line. LILO ignores input 
        parity and strips the 8th bit. The following (upper or lower case) 
        characters are used to describe the parity:  n  for no parity,  e  
        for even parity and  o  for odd parity. 
      <bits>  the number of bits in a character. Only 7 and 8 bits are 
        supported. Default is 8 if parity is "none", 7 if parity is "even" 
        or "odd". 

    If SERIAL is set, the value of DELAY is automatically raised to 20.

     Example: serial=0,2400n8 initializes COM1 with the default parameters. 
  TIMEOUT=<tsecs>  Sets a timeout (in tenths of a second) for keyboard 
    input. If no key is pressed for the specified time, the first image is 
    automatically booted. Similarly, password input is aborted if the user 
    is idle for too long. The default timeout is infinite. 
  VERBOSE=<level>  Turns on lots of progress reporting. Higher numbers give 
    more verbose output. If  -v  is additionally specified on the command 
    line, <level> is increased accordingly. The following verbosity levels 
    exist: 

      <0  only warnings and errors are shown 
      0  prints one line for each added or skipped image 
      1  mentions names of important files and devices and why they are 
        accessed. Also displays informational messages for exceptional but 
        harmless conditions and prints the version number. 
      2  displays statistics and processing of temporary files and devices 
      3  displays disk geometry information and partition table change 
        rules 
      4  lists sector mappings as they are written into the map file (i.e. 
        after compaction, in a format suitable to pass it to the BIOS) 
      5  lists the mapping of each sector (i.e. before compaction, raw) 

    When using the  -q  option, the levels have a slightly different 
    meaning: 

      0  displays only image names 
      1  also displays all global and per-image settings 
      2  displays the address of the first map sector 

Additionally, the kernel configuration parameters APPEND, INITRD, RAMDISK, 
READ-ONLY, READ-WRITE, ROOT and VGA, and the general per-image options 
FALLBACK, LOCK, OPTIONAL, PASSWORD, RESTRICTED, and SINGLE-KEY can be set 
in the global options section. They are used as defaults if they aren't 
specified in the configuration sections of the respective images. See below 
for a description.

The plethora of options may be intimidating at first, but in "normal" 
configurations, hardly any options but BOOT, COMPACT, DELAY, ROOT, and VGA 
are used.


General per-image options
- - - - - - - - - - - - -

The following options can be specified for all images, independent of their 
type: 

  ALIAS=<name>  Specifies a second name for the current entry. 
  FALLBACK=<command_line>  Specifies a string that is stored as the default 
    command line if the current image is booted. This is useful when 
    experimenting with kernels which may crash before allowing interaction 
    with the system. If using the FALLBACK option, the next reboot (e.g. 
    triggered by a manual reset or by a watchdog timer) will load a 
    different (supposedly stable) kernel. The command line by the fallback 
    mechanism is cleared by removing or changing the default command line 
    with the  -R  option, see "Change default command line". 
  LABEL=<name>  By default, LILO uses the main file name (without its path) 
    of each image specification to identify that image. A different name 
    can be used by setting the variable LABEL. 
  LOCK  Enables automatic recording of boot command lines as the defaults 
    for the following boots. This way, LILO "locks" on a choice until it is 
    manually overridden. 
  OPTIONAL  Omit this image if its main file is not available at map 
    creation time. This is useful to specify test kernels that are not 
    always present. 
  PASSWORD=<password>  Ask the user for a password when trying to load this 
    image. Because the configuration file contains unencrypted passwords 
    when using this option, it should only be readable for the super-user. 
    Passwords are always case-sensitive. 
  RESTRICTED  Relaxes the password protection by requiring a password only 
    if parameters are specified on the command line (e.g. single). 
    RESTRICTED can only be used together with PASSWORD. 
  SINGLE-KEY  Enables booting the image by hitting a single key, without 
    the need to press [Enter] afterwards. SINGLE-KEY requires that either 
    the image's label or its alias (or both) is a single character. 
    Furthermore, no other image label or alias may start with that 
    character, e.g. an entry specifying a label  linux  and an alias  l  is 
    not allowed with SINGLE-KEY. Note that you can't specify command-line 
    parameters for an entry for which only SINGLE-KEYed names exist. 

All general per-image options, with the exception of LABEL and ALIAS, can 
also be set in the global options section as defaults for all images.

Example:

password = Geheim
single-key
image = /vmlinuz
  label = linux
  alias = 1
  restricted
other = /dev/hda1
  label = dos
  alias = 2


Per-image options for kernels
- - - - - - - - - - - - - - -

Each (kernel or non-kernel) image description begins with a special 
variable (see section "Booting kernel images from a device") which is 
followed by optional variables. The following variables can be used for all 
image descriptions that describe a Linux kernel:

  APPEND=<string>  Appends the options specified in <string> to the 
    parameter line passed to the kernel. This is typically used to specify 
    parameters of hardware that can't be entirely auto-detected, e.g.
     append = "aha152x=0x140,11" 
  INITRD=<name>  Specifies the file that will be loaded at boot time as the 
    initial RAM disk. 
  LITERAL=<string>  like APPEND, but removes all other options (e.g. 
    setting of the root device). Because vital options can be removed 
    unintentionally with LITERAL, this option cannot be set in the global 
    options section. 
  RAMDISK=<size>  Specifies the size of the optional RAM disk. A value of 
    zero indicates that no RAM disk should be created. If this variable is 
    omitted, the RAM disk size configured into the boot image is used. 
  READ-ONLY  Specifies that the root file system should be mounted 
    read-only. Typically, the system startup procedure re-mounts the root 
    file system read-write later (e.g. after fsck'ing it). 
  READ-WRITE  specifies that the root file system should be mounted 
    read-write. 
  ROOT=<root_device>  Specifies the device that should be mounted as root. 
    If the special name CURRENT is used, the root device is set to the 
    device on which the root file system is currently mounted. If the root 
    has been changed with  -r , the respective device is used. If the 
    variable ROOT is omitted, the root device setting contained in the 
    kernel image is used. It can be changed with the rdev program. 
  VGA=<mode>   Specifies the VGA text mode that should be selected when 
    booting. The following values are recognized (case is ignored): 

      NORMAL  select normal 80x25 text mode. 
      EXTENDED  select 80x50 text mode. The word EXTENDED can be 
        abbreviated to EXT. 
      ASK  stop and ask for user input (at boot time). 
      <number>  use the corresponding text mode. A list of available modes 
        can be obtained by booting with  vga=ask  and pressing [Enter]. 

    If this variable is omitted, the VGA mode setting contained in the 
    kernel image is used. rdev supports manipulation of the VGA text mode 
    setting in the kernel image. 

All kernel per-image options but LITERAL can also be set in the global 
options section as defaults for all kernels.

If one of RAMDISK, READ-ONLY, READ-WRITE, ROOT, or VGA is omitted in the 
configuration file and the corresponding value in the kernel image is 
changed, LILO or the kernel will use the new value.

It is perfectly valid to use different settings for the same image, because 
LILO stores them in the image descriptors and not in the images themselves.

Example:

image = /vmlinuz
  label = lin-hd
  root = /dev/hda2
image = /vmlinuz
  label = lin-fd
  root = /dev/fd0


Boot image types
----------------

LILO can boot the following types of images: 

  - kernel images from a file. 
  - kernel images from a block device. (E.g. a floppy disk.) 
  - the boot sector of some other operating system. 

The image type is determined by the name of the initial variable of the 
configuration section.

The image files can reside on any media that is accessible at boot time. 
There's no need to put them on the root device, although this certainly 
doesn't hurt.


Booting kernel images from a file
- - - - - - - - - - - - - - - - -

The image is specified as follows: IMAGE=<name>

Example:

image = /linux

See sections "Per-image options for kernels" and "Boot image types" for the 
options that can be added in a kernel image section.


Booting kernel images from a device
- - - - - - - - - - - - - - - - - -

The range of sectors that should be mapped has to be specified. Either a 
range ( <start>-<end> ) or a start and a distance ( <start>+<number> ) have 
to be specified. <start> and <end> are zero-based. If only the start is 
specified, only that sector is mapped.

The image is specified as follows: IMAGE=<device_name> Additionally, the 
RANGE variable must be set.

Example:

image = /dev/fd0
  range = 1+512

All kernel options can also be used when booting the kernel from a device.


Booting a foreign operating system
- - - - - - - - - - - - - - - - -

LILO can even boot other operating systems, i.e. MS-DOS. To boot an other 
operating system, the name of a loader program, the device or file that 
contains the boot sector and the device that contains the partition table 
have to be specified.

The boot sector is merged with the partition table and stored in the map 
file.

Currently, the loaders chain.b and os2_d.b exist. chain.b simply starts the 
specified boot sector.* os2_d.b it a variant of chain.b that can boot OS/2 
from the second hard disk. The MAP-DRIVE option has to be used with os2_d.b 
to actually swap the drives.

  *  The boot sector is loaded by LILO's secondary boot loader before 
    control is passed to the code of chain.b.

The image is specified as follows: OTHER=<device_name> or OTHER=<file_name>

In addition to the options listen in section "Per-image options for 
kernels", the following variables are recognized: 

  CHANGE  Change the partition table according to the rules specified in 
    this CHANGE section. This option is intended for booting systems which 
    find their partitions by examining the partition table. See section 
    "Partition type changes" for details. 
  LOADER=<chain_loader>  Specifies the chain loader that should be used. If 
    it is omitted, /boot/chain.b is used. 
  MAP-DRIVE=<bios_device_code>  Instructs chain.b to installs a resident 
    driver that re-maps the floppy or hard disk drives. This way, one can 
    boot any operating system from a hard disk different from the first 
    one, as long as that operating system uses _only_ the BIOS to access 
    that hard disk.* This is known to work for PC/MS-DOS.

      *  So you should be very suspicious if the operating system requires 
        any specific configuration or even drivers to use the disk it is 
        booted from. Since there is a general trend to use optimized 
        drivers to fully exploit the hardware capabilities (e.g. 
        non-blocking disk access), booting systems from the second disk may 
        become increasingly difficult.

     MAP-DRIVE is followed by the variable TO=<bios_device_code> which 
    specifies the drive that should effectively be accessed instead of the 
    original one. The list of mappings is only searched until the first 
    match is found. It is therefore possible to "swap" drives, see the 
    second example below. 
  TABLE=<device>  Specifies the device that contains the partition table. 
    LILO does not pass partition information to the booted operating system 
    if this variable is omitted. (Some operating systems have other means 
    to determine from which partition they have been booted. E.g. MS-DOS 
    usually stores the geometry of the boot disk or partition in its boot 
    sector.) Note that /sbin/lilo must be re-run if a partition table 
    mapped referenced with TABLE is modified. 
  UNSAFE  Do not access the boot sector at map creation time. This disables 
    some sanity checks, including a partition table check. If the boot 
    sector is on a fixed-format floppy disk device, using UNSAFE avoids the 
    need to put a readable disk into the drive when running the map 
    installer. UNSAFE and TABLE are mutually incompatible. 

None of these options can be set in the global options section.

Examples:

other = /dev/hda2
  label = dos
  table = /dev/hda

other = /dev/hdb2
  label = os2
  loader = /boot/os2_d.b
  map-drive = 0x80
    to = 0x81
  map-drive = 0x81
    to = 0x80


Disk geometry
-------------

For floppies and most hard disks, LILO can obtain the disk geometry 
information from the kernel. Unfortunately, there are some exotic disks or 
adapters which may either not supply this information or which may even 
return incorrect information.

If no geometry information is available, LILO reports either the error
  geo_query_dev HDIO_GETGEO (dev 0x<number>) 
 or
  Device 0x<number>: Got bad geometry <sec>/<hd>/<cyl> 

If incorrect information is returned, booting may fail in several ways, 
typically with a partial "LILO" banner message. In this document, that is 
called a "geometry mismatch".

The next step should be to attempt setting the LBA32 or LINEAR 
configuration variable or the  -L  or  -l  command-line option. If this 
doesn't help, the entire disk geometry has to be specified explicitly. Note 
that LINEAR doesn't always work with floppy disks.

Another common use of disk sections is if an (E)IDE and a SCSI drive are 
used in the same system and the BIOS is configured to use the SCSI drive as 
the first drive. (Normally, the (E)IDE drive would be the first drive and 
the SCSI drive would be the second one.) Since LILO doesn't know how the 
BIOS is configured, it needs to be told explicitly about this arrangement. 
(See the second example below.)


Obtaining the geometry
- - - - - - - - - - -

The disk geometry parameters can be obtained by booting MS-DOS and running 
the program DPARAM.COM with the hexadecimal BIOS code of the drive as its 
argument, e.g. dparam 0x80 for the first hard disk. It displays the number 
of sectors per track, the number of heads per cylinder and the number of 
cylinders. All three numbers are one-based.

Alternatively, the geometry may also be determined by reading the 
information presented by the "setup" section of the ROM-BIOS or by using 
certain disk utilities under operating systems accessing the disk through 
the BIOS.


Specifying the geometry
- - - - - - - - - - - -

Disk geometry parameters are specified in the options section of the 
configuration file. Each disk parameter section begins with 
DISK=<disk_device>, similar to the way how boot images are specified. It is 
suggested to group disk parameter sections together, preferably at the 
beginning or the end of the options section.

For each disk, the following variables can be specified: 

  BIOS=<bios_device_code>  Is the number the BIOS uses to refer to that 
    device. Normally, it's  0x80  for the first hard disk and  0x81  for 
    the second hard disk. Note that hexadecimal numbers have to begin with 
    "0x". If BIOS is omitted, LILO tries to "guess" that number. 
  SECTORS=<sectors>  and 
  HEADS=<heads>  specify the number of sectors per track and the number of 
    heads, i.e. the number of tracks per cylinder. Both parameters have to 
    be either specified together or they have to be entirely omitted. If 
    omitted, LILO tries to obtain that geometry information from the 
    kernel. 
  CYLINDERS=<cylinders>  Specifies the number of cylinders. This value is 
    only used for sanity checks. If CYLINDERS is omitted, LILO uses the 
    information obtained from the kernel if geometry information had to be 
    requested in order to determine some other parameter. Otherwise,* it 
    just assumes the number of cylinders to be 1024, which is the cylinder 
    limit imposed by the BIOS. 
  INACCESSIBLE  Marks the device as inaccessible (for the BIOS). This is 
    useful if some disks on the system can't be read by the BIOS, although 
    LILO "thinks" they can. If one accidentally tries to use files located 
    on such disks for booting, the map installer won't notice and the 
    system becomes unbootable. The most likely use of INACCESSIBLE is to 
    prevent repetition after experiencing such a situation once. No other 
    variables may be specified if a device is configured as INACCESSIBLE. 

  *  I.e. if the BIOS device code, the number of sectors, the number of 
    heads and the partition start are specified. Note that the number of 
    cylinders may appear to vary if CYLINDERS is absent and only some of 
    the partition starts are specified.

Additionally, partition subsections can be added with 
PARTITION=<partition_device>. Each partition section can contain only one 
variable: 

  START=<partition_offset>  Specifies the zero-based number of the start 
    sector of that partition. The whole disk always has a partition offset 
    of zero. The partition offset is only necessary when using devices for 
    which the kernel does not provide that information, e.g. CD-ROMs. 

Examples:

disk = /dev/sda
  bios = 0x80
  sectors = 32
  heads = 64
  cylinders = 632
  partition = /dev/sda1
    start = 2048
  partition = /dev/sda2
    start = 204800
  partition = /dev/sda3
    start = 500000
  partition = /dev/sda4
    start = 900000

disk = /dev/sda
  bios = 0x80
disk = /dev/hda
  bios = 0x81


Partition table manipulation
----------------------------

Some non-Linux operating systems obtain information about their partitions 
(e.g. their equivalent of the root file system) from the partition table. 
If more than one such operating system is installed on a PC, they may have 
conflicting interpretations of the content of the partition table. Those 
problems can be avoided by changing the partition table, depending on which 
operating system is being booted.

Partition table changes are specified in a CHANGE section in the 
configuration file section describing the foreign operating system. Note 
that CHANGE sections are only accepted if the build-time option  
REWRITE_TABLE  is set.

The CHANGE section contains subsections for each partition whose table 
entry needs to be modified. Partitions are specified with 
PARTITION=<device_name>

Changes are applied in the sequence in which they appear in the 
configuration file. Configurations containing changes that are redundant 
either by repeating a previous change or by changing its result further are 
invalid and refused by the map installer.

Internally, all changes are expressed as rules which specify the location 
(disk and offset in the partition table), the value this location must 
contain before the change, and the value that has to be stored. As a safety 
measure, the rule is ignored if the previous value is found to be 
different.


Partition activation
- - - - - - - - - -

This option is intended for booting systems which determine their boot 
partition by examining the active flag in the partition table. The flag is 
enabled with ACTIVATE and disabled with DEACTIVATE. Note that only the 
current partition is affected. LILO does not automatically change the 
active flags of other partitions and it also allows more than one partition 
to be active at the same time.

Example:

other = /dev/sda4
  label = sco
  change
    partition = /dev/sda4
      activate
    partition = /dev/sda3
      deactivate


Partition type change rules
- - - - - - - - - - - - - -

Partition type changes are normally a transition between two possible 
values, e.g. a typical convention is to set the lowest bit in the upper 
nibble of the partition type (i.e. 0x10) in order to "hide", and to clear 
it to "unhide" a partition. LILO performs these changes based on a set of 
rules. Each rule defines the name of a partition type, its normal value, 
and the value when hidden. Those rules are defined in the options section 
of the configuration file. The section defining them begins with 
CHANGE-RULES.

The following options and variables can appear in the section: 

  RESET  Removes all previously defined rules. This is needed if a user 
    doesn't wish to use the pre-defined rules (see below). 
  TYPE=<name>  Adds a rule for the type with the specified name. Type names 
    are case-insensitive. The values are defined with NORMAL=<byte> and 
    HIDDEN=<byte>. Values can be specified as decimal or as hexadecimal 
    numbers with a leading  0x . If only one of the values is present, the 
    other value is assumed to be the same number, but with the most 
    significant bit inverted. 

LILO pre-defines rules for the three partition types of DOS partitions. The 
following example removes the pre-defined rules and creates them again:

change-rules
  reset
  type = DOS12
    normal = 0x01
    hidden = 0x11
  type = DOS16_small
    normal = 4 # hidden is 0x14
  type = DOS16_big
    hidden = 0x16


Partition type changes
- - - - - - - - - - -

Partition type changes are specified in the partition section as 
SET=<name>_<state>, where <name> is the name of the partition type, and 
<state> is its state, i.e. NORMAL or HIDDEN.

Example:

other = /dev/sda3
  label = dos
  change
    partition = /dev/sda2
      set = dos16_big_normal
    partition = /dev/sda3
      activate
      set = DOS16_big_normal

Only one SET variable is allowed per partition section. In the rare event 
that more than one SET variable is needed, further partition sections can 
be used.


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


Using keyboard translation tables
- - - - - - - - - - - - - - - - -

The keyboard translation table file is specified with the global 
configuration option  keytable=<table_file> . The complete name of the file 
has to be given.

Example:

keytable = /boot/de.klt


Installation and updates
========================


Installation
------------

This section describes the installation of LILO. See section "LILO 
de-installation" for how to uninstall LILO.


Compatibility
- - - - - - -

The kernel header files have to be in /usr/include/linux and the kernel 
usually has to be configured by running  make config  before LILO can be 
compiled.

/bin/sh has to be a real Bourne shell. bash is sufficiently compatible, but 
some ksh clones may cause problems.

A file named INCOMPAT is included in the distribution. It describes 
incompatibilities to older versions of LILO and may also contain further 
compatibility notes.


Quick installation
- - - - - - - - -

If you want to install LILO on your hard disk and if you don't want to use 
all its features, you can use the quick installation script. Read QuickInst 
for details.

QuickInst can only be used for first-time installations or to entirely 
replace an existing installation, _not_ to update or modify an existing 
installation of LILO. Be sure you've extracted LILO into a directory that 
doesn't contain any files of other LILO installations.


Files
- - -

Some of the files contained in lilo-21.tar.gz:

  lilo/README   
     This documentation in plain ASCII format. Some sections containing 
    complex tables are only included in the LaTeX version in doc/user.tex 
  lilo/INCOMPAT   
     List of incompatibilities to previous versions of LILO. 
  lilo/CHANGES   
     Change history. 
  lilo/VERSION   
     The version number of the respective release. 
  lilo/QuickInst   
     Quick installation script. 
  lilo/lilo-<version>.lsm   
     The LSM ("Linux Software Map") entry of the respective LILO release. 
  lilo/Makefile   
     Makefile to generate everything else. 
  lilo/*.c, lilo/*.h   
     LILO map installer C source and common header files. 
  lilo/*.S   
     LILO boot loader assembler source. 
  lilo/activate.c   
     C source of a simple boot partition setter. 
  lilo/dparam.s   
     Assembler source of a disk parameter dumper. 
  lilo/mkdist   
     Shell script used to create the current LILO distribution. 
  lilo/keytab-lilo.pl   
     Perl script to generate keyboard translation tables. 
  lilo/doc/README   
     Description of how to generate the documentation. 
  lilo/doc/Makefile   
     Makefile used to convert the LaTeX source into either DVI output or 
    the plain ASCII README file. 
  lilo/doc/user.tex   
     LaTeX source of LILO's user's guide (this document). 
  lilo/doc/tech.tex   
     LaTeX source of LILO's technical overview. 
  lilo/doc/*.fig   
     Various xfig pictures used in the technical overview. 
  lilo/doc/fullpage.sty   
     Style file to save a few square miles of forest. 
  lilo/doc/rlatex   
     Shell script that invokes LaTeX repeatedly until all references have 
    settled. 
  lilo/doc/t2a.pl   
     Perl script to convert the LaTeX source of the user's guide to plain 
    ASCII. 

Files created after  make  in lilo/ (among others):

  lilo/boot.b   
     Combined boot sector.  make install  puts this file into /boot 
  lilo/chain.b   
     Generic chain loader.  make install  puts this file into /boot 
  lilo/os2_d.b   
     Chain loader to load OS/2 from the second hard disk.  make install  
    puts this file into /boot 
  lilo/lilo   
     LILO (map) installer.  make install  puts this file into /sbin 
  lilo/activate   
     Simple boot partition setter. 
  lilo/dparam.com   
     MS-DOS executable of the disk parameter dumper. 


Normal first-time installation
- - - - - - - - - - - - - - -

First, you have to install the LILO files:

  - extract all files from lilo-<version>.tar.gz in a new directory.* 
  - configure the Makefile (see section "Build-time configuration") 
  - run  make  to compile and assemble all parts. 
  - run  make install  to copy all LILO files to the directories where 
    they're installed. /sbin should now contain the file lilo, /usr/sbin 
    should contain keytab-lilo.pl, and /boot should contain boot.b, 
    chain.b, and os2_d.b. 

  *  E.g. /usr/src/lilo

If you want to use LILO on a non-standard disk, you might have to determine 
the parameters of your disk(s) and specify them in the configuration file. 
See section "Disk geometry" for details. If you're using such a 
non-standard system, the next step is to test LILO with the boot sector on 
a floppy disk:

  - insert a blank (but low-level formatted) floppy disk into /dev/fd0. 
  - run  echo image=<kernel_image>  |
      /sbin/lilo -C - -b /dev/fd0 -v -v -v 
     If you've already installed LILO on your system, you might not want to 
    overwrite your old map file. Use the  -m  option to specify an 
    alternate map file name. 
  - reboot. LILO should now load its boot loaders from the floppy disk and 
    then continue loading the kernel from the hard disk. 

Now, you have to decide, which boot concept you want to use. Let's assume 
you have a Linux partition on /dev/hda2 and you want to install your LILO 
boot sector there. The DOS-MBR loads the LILO boot sector.

  - get a working boot disk, e.g. an install or recovery disk. Verify that 
    you can boot with this setup and that you can mount your Linux 
    partition(s) with it. 
  - if the boot sector you want to overwrite with LILO is of any value 
    (e.g. it's the MBR or if it contains a boot loader you might want to 
    use if you encounter problems with LILO), you should mount your boot 
    disk and make a backup copy of your boot sector to a file on that 
    floppy, e.g. dd if=/dev/hda of=/fd/boot_sector bs=512 count=1 
  - create the configuration file /etc/lilo.conf, e.g.
     <global settings>
     <image specification>
       <per-image options>
     ...
     Be sure to use absolute paths for all files. Relative paths may cause 
    unexpected behaviour when using the  -r  option. 
  - now, you can check what LILO would do if you were about to install it 
    on your hard disk:
     /sbin/lilo -v -v -v -t 
  - if you need some additional boot utility (i.e. BOOTACTV), you should 
    install that now 
  - run /sbin/lilo to install LILO on your hard disk 
  - if you have to change the active partition, use fdisk or activate to do 
    that 
  - reboot 


Build-time configuration
- - - - - - - - - - - -

Certain build-time parameters can be configured. They can either be edited 
in the top-level Makefile or they can be stored in a file 
/etc/lilo.defines. Settings in the Makefile are ignored if that file 
exists.

The following items can be configured: 

   BEEP   Enables beeping after displaying "LILO". This is useful on 
    machines which don't beep at the right time when booting and when 
    working over a serial console. This option is disabled by default. 
   IGNORECASE   Makes image name matching case-insensitive, i.e. "linux" 
    and "Linux" are identical. This option is enabled by default. Note that 
    password matching is always case-sensitive. 
   LARGE_EDBA   Loads LILO at a lower address in order to leave more space 
    for the EBDA (Extended BIOS Data Area). This is necessary on some 
    recent MP systems. Note that enabling  LARGE_EDBA  reduces the maximum 
    size of "small" images (e.g. "Image" or "zImage"). 
   NO1STDIAG   Do not generate diagnostics on read errors in the first 
    stage boot loader. This avoids possibly irritating error codes if the 
    disk controller has transient read problems. This option is disabled by 
    default. 
   NODRAIN   The boot loader empties the keyboard buffer when starting, 
    because it may contain garbage on some systems. Draining the keyboard 
    buffer can be disabled by setting the  NODRAIN  option.  NODRAIN  is 
    disabled by default. 
   NOINSTDEF   If the option INSTALL is omitted, don't install a new boot 
    sector, but try to modify the old boot sector instead. This option is 
    disabled by default. 
   ONE_SHOT   Disables the command-line timeout (configuration variable 
    TIMEOUT) if any key is pressed. This way, very short timeouts can be 
    used if PROMPT is set.  ONE_SHOT  is disabled by default. 
   READONLY   Disallows overwriting the default command line sector of the 
    map file. This way, command lines set with  -R  stay in effect until 
    they are explicitly removed.  READONLY  also disables LOCK, FALLBACK, 
    and everything enabled by  REWRITE_TABLE . This option is disabled by 
    default. 
   REWRITE_TABLE   Enables rewriting the partition table at boot time. This 
    may be necessary to boot certain operating systems who expect the 
    active flag to be set on their partition or who need changes in 
    partition types. See also section "Partition table manipulation". This 
    option is _dangerous_ and it is disabled by default. 
   USE_TMPDIR   Use the directory indicated in the  TMPDIR  environment 
    variable when creating temporary device files. If  TMPDIR  is not set 
    or if LILO is compiled without  USE_TMPDIR , temporary device files are 
    created in /tmp.* This option is disabled by default. 
   VARSETUP   Enables the use of variable-size setup segments. This option 
    is enabled by default and is only provided to fall back to fixed-size 
    setup segments in the unlikely case of problems when using prehistoric 
    kernels. 
   XL_SECS=<sectors>   Enable support for extra large (non-standard) floppy 
    disks. The number of sectors is set in the BIOS disk parameter table to 
    the specified value. Note that this hack may yield incorrect behaviour 
    on some systems. This option is disabled by default. 

  *  Note that, while honoring  TMPDIR  is the "right" thing to do, the 
    fact that LILO has to create temporary device files at all may indicate 
    that the operating environment is not completely set up, so  TMPDIR  
    may point to an invalid location.

/etc/lilo.defines should be used if one wishes to make permanent 
configuration changes. The usual installation procedures don't touch that 
file. Example:

-DIGNORECASE -DONE_SHOT

After changing the build-time configuration, LILO has to be recompiled with 
the following commands:

make spotless
make


Floppy disk installation
- - - - - - - - - - - -

In some cases*, it may be desirable to install LILO on a floppy disk in a 
way that it can boot a kernel without accessing the hard disk.

  *  E.g. if no hard disk is accessible through the BIOS.

The basic procedure is quite straightforward (see also section "BIOS 
restrictions"): 

  - a file system has to be created on the file system 
  - the kernel and boot.b have to be copied to the floppy disk 
  - /sbin/lilo has to be run to create the map file 

This can be as easy as

/sbin/mke2fs /dev/fd0
[ -d /fd ] || mkdir /fd
mount /dev/fd0 /fd
cp /boot/boot.b /fd
cp /zImage /fd
echo image=/fd/zImage label=linux |
  /sbin/lilo -C - -b /dev/fd0 -i /fd/boot.b -c -m /fd/map
umount /fd

The command line of /sbin/lilo is a little tricky.  -C -  takes the 
configuration from standard input (naturally, one could also write the 
configuration into a file),  -b /dev/fd0  specifies that the boot sector is 
written to the floppy disk,  -i /fd/boot.b  takes the first and second 
stage loaders from the floppy,  -c  speeds up the load process, and  -m 
/fd/map  puts the map file on the floppy too.


Updates
-------

LILO is affected by updates of kernels, the whole system and (trivially) of 
LILO itself. Typically, only /sbin/lilo has to be run after any of those 
updates and everything will be well again (at least as far as LILO is 
concerned).


LILO update
- - - - - -

Before updating to a new version of LILO, you should read at least the file 
INCOMPAT which describes incompatibilities with previous releases.

After that, the initial steps are the same as for a first time 
installation: extract all files, configure the Makefile, run  make  to 
build the executables and run  make install  to install the files.

The old versions of boot.b, chain.b, etc. are automatically renamed to 
boot.old, chain.old, etc. This is done to ensure that you can boot even if 
the installation procedure does not finish. boot.old, chain.old, etc. can 
be deleted after the map file is rebuilt.

Because the locations of boot.b, chain.b, etc. have changed and because the 
map file format may be different too, you have to update the boot sector 
and the map file. Run /sbin/lilo to do this.


Kernel update
- - - - - - -

Whenever any of the kernel files that are accessed by LILO is moved or 
overwritten, the map has to be re-built.* Run /sbin/lilo to do this.

  *  It is advisable to keep a second, stable, kernel image that can be 
    booted if you forget to update the map after a change to your usual 
    kernel image.

The kernel has a make target "zlilo" that copies the kernel to /vmlinuz and 
runs /sbin/lilo.


System upgrade
- - - - - - -

Normally, system upgrades (i.e. installation or removal of packages, 
possibly replacement of a large part of the installed binaries) do not 
affect LILO. Of course, if a new kernel is installed in the process, the 
normal kernel update procedure has to be followed (see section "Kernel 
update"). Also, if kernels are removed or added, it may be necessary to 
update the configuration file.

If LILO is updated by this system upgrade, /sbin/lilo should be run before 
booting the upgraded system. It is generally a good idea not to rely on the 
upgrade procedure to perform this essential step automatically.

However, system upgrades which involve removal and re-creation of entire 
partitions (e.g. /, /usr, etc.) are different. First, they should be 
avoided, because they bear a high risk of losing other critical files, e.g. 
the /etc/XF86Config you've spent the last week fiddling with. If an upgrade 
really has to be performed in such a brute-force way, this is equal with 
total removal of LILO, followed by a new installation. Therefore, the 
procedures described in the sections "LILO de-installation" and "LILO 
update" have to be performed. If you've forgotten to make a backup copy of 
/etc/lilo.conf before the destructive upgrade, you might also have to go 
through section "Normal first-time installation" again.


LILO de-installation
--------------------

In order to stop LILO from being invoked when the system boots, its boot 
sector has to be either removed or disabled. All other files belonging to 
LILO can be deleted _after_ removing the boot sector, if desired.*

  *  Backup copies of old boot sectors may be needed when removing the boot 
    sector. They are stored in /boot.

Again, _when removing Linux, LILO must be de-installed before (!) its files 
(/boot, etc.) are deleted._ This is especially important if LILO is 
operating as the MBR.

LILO 14 (and newer) can be de-installed with lilo -u. If LILO 14 or newer 
is currently installed, but the first version of LILO installed was older 
than 14, lilo -U may work. When using -U, the warning at the end of this 
section applies.

If LILO's boot sector has been installed on a primary partition and is 
booted by the "standard" MBR or some partition switcher program, it can be 
disabled by making a different partition active. MS-DOS' FDISK, Linux fdisk 
or LILO's activate can do that.

If LILO's boot sector is the master boot record (MBR) of a disk, it has to 
be replaced with a different MBR, typically MS-DOS' "standard" MBR. When 
using MS-DOS 5.0 or above, the MS-DOS MBR can be restored with FDISK /MBR. 
This only alters the boot loader code, not the partition table.

LILO automatically makes backup copies when it overwrites boot sectors. 
They are named /boot/boot.<nnnn>, with <nnnn> corresponding to the device 
number, e.g.  0300  is /dev/hda,  0800  is /dev/sda, etc. Those backups can 
be used to restore the old MBR if no easier method is available. The 
commands are
  dd if=/boot/boot.0300 of=/dev/hda bs=446 count=1  or
  dd if=/boot/boot.0800 of=/dev/sda bs=446 count=1 
 respectively.

_WARNING:_ Some Linux distributions install boot.<nnnn> files from the 
system where the distribution was created. Using those files may yield 
unpredictable results. Therefore, the file creation date should be 
carefully checked.


Installation of other operating systems
---------------------------------------

Some other operating systems (e.g. MS-DOS 6.0) appear to modify the MBR in 
their install procedures. It is therefore possible that LILO will stop to 
work after such an installation and Linux has to be booted from floppy 
disk. The original state can be restored by either re-running /sbin/lilo 
(if LILO is installed as the MBR) or by making LILO's partition active (if 
it's installed on a primary partition).

It is generally a good idea to install LILO after the other operating 
systems have been installed. E.g. OS/2 is said to cause trouble when 
attempting to add it to an existing Linux system. (However, booting from 
floppy and running /sbin/lilo should get around most interferences.)

Typically, the new operating system then has to be added to LILO's 
configuration (and /sbin/lilo has to be re-run) in order to boot it.

See also section "Other problems" for a list of known problems with some 
other operating systems.


Troubleshooting
===============

All parts of LILO display some messages that can be used to diagnose 
problems.


Map installer warnings and errors
---------------------------------

Most messages of the map installer (/sbin/lilo) should be self-explanatory. 
Some messages that indicate common errors are listed below. They are 
grouped into fatal errors and warnings (non-fatal errors).


Fatal errors
- - - - - - 

   Boot sector of <device_name> doesn't have a boot signature   
   Boot sector of <device_name> doesn't have a LILO signature    
     The sector from which LILO should be uninstalled doesn't appear to be 
    a LILO boot sector. 
   Can't put the boot sector on logical partition <number>    
     An attempt has been made to put LILO's boot sector on the current root 
    file system partition which is on a logical partition. This usually 
    doesn't have the desired effect, because common MBRs can only boot 
    primary partitions. This check can be bypassed by explicitly specifying 
    the boot partition with the  -b  option or by setting the configuration 
    variable BOOT. 
   Checksum error    
     The descriptor table of the map file has an invalid checksum. Refresh 
    the map file _immediately_ ! 
   Device 0x<number>: Configured as inaccessible.    
     There is a DISK section entry indicating that the device is 
    inaccessible from the BIOS. You should check carefully that all files 
    LILO tries to access when booting are on the right device. 
   Device 0x<number>: Got bad geometry <sec>/<hd>/<cyl>    
     The device driver for your SCSI controller does not support geometry 
    detection. You have to specify the geometry explicitly (see section 
    "Disk geometry"). 
   Device 0x<number>: Invalid partition table, entry <number>    
     The 3D and linear addresses of the first sector of the specified 
    partition don't correspond. This is typically caused by partitioning a 
    disk with a program that doesn't align partitions to tracks and later 
    using PC/MS-DOS or OS/2 on that disk. LILO can attempt to correct the 
    problem, see "General per-image options". 
   Device 0x<number>: Partition type 0x<number> does not seem suitable for 
  a LILO boot sector    
     The location where the LILO boot sector should be placed does not seem 
    to be suitable for that. (See also also section "Disk organization"). 
    You should either adjust the partition type to reflect the actual use 
    or put the boot sector on a different partition. This consistency check 
    only yields a warning (i.e. LILO continues) if the option IGNORE-TABLE 
    is set. 
   <device_name> is not a valid partition device    
     The specified device is either not a device at all, a whole disk, or a 
    partition on a different disk than the one in whose section its entry 
    appears. 
   <device_name> is not a whole disk device    
     Only the geometry of whole disks (e.g. /dev/hda, /dev/sdb, etc.) can 
    be redefined when using DISK sections. 
   DISKTAB and DISK are mutually exclusive    
     You cannot use a disktab file and disk geometry definitions in the 
    configuration file at the same time. Maybe /etc/disktab was 
    accidentally used, because that's the default for 
    backward-compatibility. You should delete /etc/disktab after completing 
    the transition to DISK sections. 
   Duplicate entry in partition table    
     A partition table entry appears twice. The partition table has to be 
    fixed with fdisk. 
   Duplicate geometry definition for <device_name>    
     A disk or partition geometry definition entry for the same device 
    appears twice in the configuration file. Note that you mustn't write a 
    partition section for the whole disk - its start sector is always the 
    first sector of the disk. 
   First sector of <device> doesn't have a valid boot signature    
     The first sector of the specified device does not appear to be a valid 
    boot sector. You might have confused the device name.* 
   geo_comp_addr: Cylinder <number> beyond end of media (<number>)    
     A file block appears to be located beyond the last cylinder of the 
    disk. This probably indicates an error in the disk geometry 
    specification (see section "Disk geometry") or a file system 
    corruption. 
   geo_comp_addr: Cylinder number is too big (<number> > 1023)    
     Blocks of a file are located beyond the 1024th cylinder of a hard 
    disk. LILO can't access such files, because the BIOS limits cylinder 
    numbers to the range 0...1023. Try moving the file to a different 
    place, preferably a partition that is entirely within the first 1024 
    cylinders of the disk. 
   Hole found in map file (<location>)    
     The map installer is confused about the disk organization. Please 
    report this error. 
   <item> doesn't have a valid LILO signature    
     The specified item has been located, but is not part of LILO. 
   <item> has an invalid stage code (<number>)    
     The specified item has probably been corrupted. Try re-building LILO. 
   <item> is version <number>. Expecting version <number>.    
     The specified entity is either too old or too new. Make sure all parts 
    of LILO (map installer, boot loaders and chain loaders) are from the 
    same distribution. ** 
   Kernel <name> is too big    
     The kernel image (without the setup code) is bigger than 512 kbytes 
    (or 448 kbytes, if built with  LARGE_EDBA ). LILO would overwrite 
    itself when trying to load such a kernel. This limitation only applies 
    to old kernels which are loaded below 0x10000 (e.g. "Image" or 
    "zImage"). Try building the kernel with "bzImage". If this is 
    undesirable for some reason, try removing some unused drivers and 
    compiling the kernel again. This error may also occur if the kernel 
    image is damaged or if it contains trailing "junk", e.g. as the result 
    of copying an entire boot floppy to the hard disk. 
   LOCK and FALLBACK are mutually exclusive    
     Since LOCK and FALLBACK both change the default command line, they 
    can't be reasonably used together. 
   Map <path> is not a regular file.    
     This is probably the result of an attempt to omit writing a map file, 
    e.g. with  -m /dev/null . The  -t  option should be used to accomplish 
    this. 
   Must specify SECTORS and HEADS together    
     It is assumed that disks with a "strange" number of sectors will also 
    have a "strange" number of heads. Therefore, it's all or nothing. 
   No geometry variables allowed if INACCESSIBLE    
     If a device is configured as INACCESSIBLE (see section "Specifying the 
    geometry"), its DISK section must not contain any geometry variables. 
   No image <image> is defined    
     The command line specified either with the  -R  option or with 
    FALLBACK does not contain the name of a valid image. Note that optional 
    images which have not been included in the map file are not considered 
    as valid. 
   Partition entry not found    
     The partition from which an other operating system should be booted 
    isn't listed in the specified partition table. This either means that 
    an incorrect partition table has been specified or that you're trying 
    to boot from a logical partition. The latter usually doesn't work. You 
    can bypass this check by omitting the partition table specification 
    (e.g. omitting the variable TABLE). 
   Single-key clash: "<name>" vs. "<name>"    
     The specified image labels or aliases conflict because one of them is 
    a single character and has the SINGLE-KEY option set, and the other 
    name begins with that character. 
   Sorry, don't know how to handle device <number>    
     LILO uses files that are located on a device for which there is no 
    easy way to determine the disk geometry. Such devices have to be 
    explicitly described, see section "Disk geometry". 
   This LILO is compiled READONLY and doesn't support ...    
     If LILO is not allowed to write to the disk at boot time (see section 
    "Build-time configuration"), options like LOCK and FALLBACK are 
    unavailable. 
   This LILO is compiled without REWRITE_TABLE and doesn't support ...    
     If LILO is not allowed to rewrite partition tables at boot time (see 
    section "Partition table manipulation"), options like ACTIVATE and SET 
    (in a CHANGE section) are unavailable. You may also get this error if 
    LILO is compiled with  READONLY  enabled. 
   Timestamp in boot sector of <device> differs from date of <file>    
     The backup copy of the boot sector does not appear to be an ancestor 
    of the current boot sector. If you are absolutely sure that the boot 
    sector is indeed correct, you can bypass this check by using  -U  
    instead of  -u . 
   Trying to map files from unnamed device 0x<number> (NFS ?)    
     This is probably the same problem as described below, only with the 
    root file system residing on NFS. 
   Trying to map files from your RAM disk. Please check -r option or ROOT 
  environment variable.    
     Most likely, you or some installation script is trying to invoke LILO 
    in a way that some of the files is has to access reside on the RAM 
    disk. Normally, the  ROOT  environment variable should be set to the 
    mount point of the effective root device if installing LILO with a 
    different root directory. See also sections "Create or update map" and 
    "Normal first-time installation". 
   VGA mode presetting is not supported by your kernel.    
     Your kernel sources appear to be very old ('93 ?). LILO may work on 
    your system if you remove the VGA option. 
   write <item>: <error_reason>    
     The disk is probably full or mounted read-only. 

  *  Because different partition programs may display the partitions in a 
    different order, it is possible that what you think is your first 
    partition isn't /dev/hda1, etc. A good method to verify the content of 
    a partition is to try to mount it.

  **  The expected version number may be different from the version number 
    of the LILO package, because file version numbers are only increased 
    when the file formats change.


Warnings
- - - -

Messages labeled with "Warning" can be turned off with the NOWARN option.

   FIGETBSZ <file_name>: < error_reason>    
     The map installer is unable to determine the block size of a file 
    system. It assumes a block size of two sectors (1kB). 
   Ignoring entry '<variable_name>'    
     The command-line option corresponding to the specified variable is 
    set. Therefore, the configuration file entry is ignored. 
   Setting DELAY to 20 (2 seconds)    
     Because accidentally booting the wrong kernel or operating system may 
    be very inconvenient on systems that are not run from a local display, 
    the minimum delay is two seconds if the SERIAL variable is set. 
   (temp) <item>: <error_reason>    
     Deleting a temporary file has failed for the specified reason. 
   Warning: BIOS drive 0x<number> may not be accessible    
     Because most BIOS versions only support two floppies and two hard 
    disks, files located on additional disks may be inaccessible. This 
    warning indicates that some kernels or even the whole system may be 
    unbootable. 
   Warning: COMPACT may conflict with LINEAR on some systems    
     Please see section "Other problems" for a description of this problem. 
   Warning: <config_file> should be owned by root    
     In order to prevent users from compromising system integrity, the 
    configuration file should be owned by root and write access for all 
    other users should be disabled. 
   Warning: <config_file> should be readable only for root if using 
  PASSWORD    
     Users should not be allowed to read the configuration file when using 
    the PASSWORD option, because then, it contains unencrypted passwords. 
   Warning: <config_file> should be writable only for root    
     See " Warning: <config_file> should be owned by root ". 
   Warning: device 0x<number> exceeds 1024 cylinder limit    
     A disk or partition exceeds the 1024 cylinder limit imposed by the 
    BIOS. This may result in a fatal error in the current installation run 
    or in later installation runs. See " geo_comp_addr: Cylinder number is 
    too big (<number> > 1023) " for details. 
   Warning: <device> is not on the first disk    
     The specified partition is probably not on the first disk. LILO's boot 
    sector can only be booted from the first disk unless some special boot 
    manager is used. 
   WARNING: The system is unbootable !    
     One of the last installation steps has failed. This warning is 
    typically followed by a fatal error describing the problem. 


Boot loader messages
--------------------

The boot loader generates three types of messages: progress and error 
messages while it is loading, messages indicating disk access errors, and 
error messages in response to invalid command-line input. Since messages of 
the latter type are usually self-explanatory, only the two other categories 
are explained.


LILO start message
- - - - - - - - -

When LILO loads itself, it displays the word "LILO". Each letter is printed 
before or after performing some specific action. If LILO fails at some 
point, the letters printed so far can be used to identify the problem. This 
is described in more detail in the technical overview.

Note that some hex digits may be inserted after the first "L" if a 
transient disk problem occurs. Unless LILO stops at that point, generating 
an endless stream of error codes, such hex digits do not indicate a severe 
problem.

  (<nothing>)  No part of LILO has been loaded. LILO either isn't installed 
    or the partition on which its boot sector is located isn't active. 
   L <error> ...   The first stage boot loader has been loaded and started, 
    but it can't load the second stage boot loader. The two-digit error 
    codes indicate the type of problem. (See also section "Disk error 
    codes".) This condition usually indicates a media failure or a geometry 
    mismatch (e.g. bad disk parameters, see section "Disk geometry"). 
   LI   The first stage boot loader was able to load the second stage boot 
    loader, but has failed to execute it. This can either be caused by a 
    geometry mismatch or by moving /boot/boot.b without running the map 
    installer. 
   LIL   The second stage boot loader has been started, but it can't load 
    the descriptor table from the map file. This is typically caused by a 
    media failure or by a geometry mismatch. 
   LIL?   The second stage boot loader has been loaded at an incorrect 
    address. This is typically caused by a subtle geometry mismatch or by 
    moving /boot/boot.b without running the map installer. 
   LIL-   The descriptor table is corrupt. This can either be caused by a 
    geometry mismatch or by moving /boot/map without running the map 
    installer. 
   LILO   All parts of LILO have been successfully loaded. 


Disk error codes
- - - - - - - -

If the BIOS signals an error when LILO is trying to load a boot image, the 
respective error code is displayed. The following BIOS error codes are 
known:

   0x00   "Internal error". This code is generated by the sector read 
    routine of the LILO boot loader whenever an internal inconsistency is 
    detected. This might be caused by corrupt files. Try re-building the 
    map file. Another possible cause for this error are attempts to access 
    cylinders beyond 1024 while using the LINEAR option. See section "BIOS 
    restrictions" for more details and for how to solve the problem. 
   0x01   "Illegal command". This shouldn't happen, but if it does, it may 
    indicate an attempt to access a disk which is not supported by the 
    BIOS. See also "Warning: BIOS drive 0x<number> may not be accessible" 
    in section "Warnings". 
   0x02   "Address mark not found". This usually indicates a media problem. 
    Try again several times. 
   0x03   "Write-protected disk". This should only occur on write 
    operations. 
   0x04   "Sector not found". This typically indicates a geometry mismatch. 
    If you're booting a raw-written disk image, verify whether it was 
    created for disks with the same geometry as the one you're using. If 
    you're booting from a SCSI disk or a large IDE disk, you should check, 
    whether LILO has obtained correct geometry data from the kernel or 
    whether the geometry definition corresponds to the real disk geometry. 
    (See section "Disk geometry".) Removing COMPACT may help too. So may 
    adding LBA32 or LINEAR. 
   0x06   "Change line active". This should be a transient error. Try 
    booting a second time. 
   0x07   "Invalid initialization". The BIOS failed to properly initialize 
    the disk controller. You should control the BIOS setup parameters. A 
    warm boot might help too. 
   0x08   "DMA overrun". This shouldn't happen. Try booting again. 
   0x09   "DMA attempt across 64k boundary". This shouldn't happen, but may 
    inicate a disk geometry mis-match. Try omitting the COMPACT option. You 
    may need to specify the disk geometry yourself. 
   0x0C   "Invalid media". This shouldn't happen and might be caused by a 
    media error. Try booting again. 
   0x10   "CRC error". A media error has been detected. Try booting several 
    times, running the map installer a second time (to put the map file at 
    some other physical location or to write "good data" over the bad 
    spot), mapping out the bad sectors/tracks and, if all else fails, 
    replacing the media. 
   0x11   "ECC correction successful". A read error occurred, but was 
    corrected. LILO does not recognize this condition and aborts the load 
    process anyway. A second load attempt should succeed. 
   0x20   "Controller error". This shouldn't happen. 
   0x40   "Seek failure". This might be a media problem. Try booting again. 
   0x80   "Disk timeout". The disk or the drive isn't ready. Either the 
    media is bad or the disk isn't spinning. If you're booting from a 
    floppy, you might not have closed the drive door. Otherwise, trying to 
    boot again might help. 
   0xBB   "BIOS error". This shouldn't happen. Try booting again. If the 
    problem persists, removing the COMPACT option or adding/removing LINEAR 
    or LBA32 might help. 

If the error occurred during a write operation, the error code (two hex 
digits) is prefixed with a "W". Although write errors don't affect the boot 
process, they might indicate a severe problem, because they usually imply 
that LILO has tried to write to an invalid location. If spurious write 
errors occur on a system, it might be a good idea to configure LILO to run 
read-only (see section "Build-time configuration").

Generally, invalid geometry and attempts to use more than two disks without 
a very modern BIOS may yield misleading error codes. Please check carefully 
if /sbin/lilo doesn't emit any warnings. Then try using the LINEAR or LBA32 
option (see section "Global options").


Other problems
--------------

This section contains a collection of less common problems that have been 
observed. See also section "Installation of other operating systems" for 
general remarks on using LILO with other operating systems. Some of the 
problems are obscure and so are the work-arounds.

  - If LILO doesn't go away even if you erase its files, format your Linux 
    partition, etc., you've probably installed LILO as your MBR and you've 
    forgotten to deinstall it before deleting its files. See section "LILO 
    de-installation" for what you can do now. 
  - For yet unknown reasons, LILO may fail on some systems with AMI BIOS if 
    the "Hard Disk Type 47 RAM area" is set to "0:300" instead of "DOS 1K". 
  - Some disk controller BIOSes perform disk geometry/address translations 
    that are incompatible with the way the device's geometry is seen from 
    Linux, i.e. without going through the BIOS. Particularly, large IDE 
    disks and some PCI SCSI controllers appear to have this problem. In 
    such cases, either the translated geometry has to be specified in a 
    DISK section or the sector address translation can be deferred by using 
    the LINEAR option. In a setup where floppies are not normally used for 
    booting, the LINEAR approach should be preferred, because this avoids 
    the risk of specifying incorrect numbers. 
  - OS/2 is said to be bootable from a logical partition with LILO acting 
    as the primary boot selector if LILO is installed on the MBR, the OS/2 
    BootManager is on an active primary partition and LILO boots 
    BootManager. Putting LILO on an extended partition instead is said to 
    crash the OS/2 FDISK in this scenario.

     Note that booting LILO from BootManager (so BootManager is the primary 
    selector) or booting OS/2 directly from a primary partition (without 
    BootManager) should generally work. See also section "Installation of 
    other operating systems". 
  - Windows NT is reported to be bootable with LILO when LILO acts as the 
    MBR and the Windows NT boot loader is on the DOS partition. However, 
    NT's disk manager complains about LILO's MBR when trying to edit the 
    partition table. 
  - Some PC UNIX systems (SCO and Unixware have been reported to exhibit 
    this problem) depend on their partition being active. See section 
    "Partition table manipulation" for how this can be accomplished. 
  - Future Domain TMC-1680 adapters with the BIOS versions 3.4 and 3.5 
    assign BIOS device numbers in the wrong order, e.g. on a two-disk 
    system, /dev/sda becomes  0x81  and /dev/sdb becomes  0x80 . This can 
    be fixed with the following DISK section:
     disk=/dev/sda bios=0x81 disk=/dev/sdb bios=0x80
     Note that this is only valid for a two-disk system. In three-disk 
    systems, /dev/sdc would become  0x80 , etc. Also, single-disk systems 
    don't have this problem (and the "fix" would break them). 
  - Some BIOSes don't properly recognize disks with an unusual partition 
    table (e.g. without any partition marked active) and refuse to boot 
    from them. This can also affect the second hard disk and the problem 
    may only occur if the system is booted in a particular way (e.g. only 
    after a cold boot). 
  - On some systems, using LINEAR and COMPACT or LBA32 and COMPACT together 
    leads to a boot failure. The exact circumstances under which this 
    happens are still unknown. 
