lilo.conf (5)

Leading comments

@(#)lilo.conf.5
This page is based on the lilo docs, which carry the following
COPYING condition:

LILO program code, documentation and auxiliary programs are
Copyright 1992-1998 Werner Almesberger.
Extensions to LILO, documentation and auxiliary programs are
Copyright 1999-2005 John Coffman.
Extensions to LILO, documentation and auxiliary programs are
Copyright 2009-2011 Joachim Wiedorn.

All rights reserved by the respective copyright holders.

Redistribution and use in source and binary fo...

(The comments found at the beginning of the groff file "man5/lilo.conf.5".)

NAME

lilo.conf - configuration file for lilo

DESCRIPTION

This file, by default /etc/lilo.conf, is read by the boot loader installer 'lilo' (see lilo(8)).

It might look as follows:

# /etc/lilo.conf
#
#  global options:
boot=/dev/hda
prompt
timeout=150
lba32
compact
vga=normal
root=/dev/hda1
read-only
menu-title=" John's Computer "
#
### bootable kernel images ###
image=/boot/vmlinuz-2.6.29-1-i386
     label=try
     initrd=/boot/initrd.img-2.6.29-1-i386
image=/boot/vmlinuz-2.4.33-1-i386
     label=2.4.33
image=/tamu/vmlinuz
     label=tamu
     initrd=/tamu/initrd.img
     root=/dev/hdb2
     vga=ask
#
### other operating systems ###
other=/dev/hda3
     label=PCDOS
     boot-as=0x80    # must be C:
other=/dev/hdb1
     label=WinXP
     boot-as=0x80    # must be C:
other=/dev/hdb5
     label=oldDOS
     loader=chain
     table=/dev/hdb5

This configuration file specifies that lilo uses the Master Boot Record on /dev/hda. (For a discussion of the various ways to use lilo, and the interaction with other operating systems, see html/user_21-5.html inside the old documentation.)

When booting, the boot loader will issue its boot: prompt and wait for you to enter the label of the kernel (and any options) which you wish to boot. At any time you may hit [Tab] to see a list of kernel/other labels. Alternately, if the menu boot loader is installed, a menu of boot options will be presented for your selection. The title of this menu is overridden with the menu title specification in this configuration file. If you enter nothing, then the default kernel image, the first mentioned, (in the example /boot/vmlinuz-2.6.29-1-i386) will be booted after a timeout of 15 seconds (150 deciseconds). There may be at least 16 images mentioned in lilo.conf. (The exact number depends upon compilation options.)

As can be seen above, a configuration file starts with a number of global options (the top 9 lines in the example), followed by descriptions of the options for the various images. An option in an image description will override a global option.

Comment lines may appear anywhere, and begin with the "#" character.

GLOBAL OPTIONS

There are many possible keywords. The description below is almost literally from html/user_21-5.html inside the old documentation (just slightly abbreviated).

backup=<backup-file>

Specifies the location where a copy of any modified boot sector will be saved in a file. 'backup=' may specify this location in one of three ways: a directory where the default backup file 'boot.NNNN' will be created; a file pathname template to which the '.NNNN' suffix will be added; or the full file pathname, which must include the correct '.NNNN' suffix. All RAID installations should use only the first two alternatives, as multiple backups may be created. The '.NNNN' suffix is the hexadecimal representation of the major and minor device numbers of the device or partition. If this option is not specified, the default name of boot sector backups is '/boot/boot.NNNN'. If a backup already exists, it will be preserved, rather than overwritten. C.f., force-backup= below.

bios-passes-dl=<option>

The option is indicated as yes, no, or unknown. If not specified, a value of "unknown" is assumed, unless additional information is available to the boot installer. When "no" is specified, it indicates that the BIOS is known not to pass the current boot device code to the boot loader in the DL register. Its only function at this point is experimental, as certain RAID installations may benefit from knowing that the BIOS is 100% reliable. Its use should be considered experimental.

This option may be specified on the command line with the '-Z' switch: yes=1, no=0.

bitmap=<bitmap-file>

Specifies use of a 640x480x16 (VGA BIOS) or 640x480x256 (VGA/VESA BIOS) bitmap file as the background on which a boot menu is displayed. May not be used if 'message=' is specified. Use of this option will select a bitmap-capable boot loader, unless overridden with "install=" (see below).

When a bitmap file is specified as a background screen during the boot process, the color selection and layout of the text which overlays the graphic image must be specified in one of two ways.

One way is the use of header information in the bitmap image (*.bmp) file: From a text file with all the information about 'bmp-colors', 'bmp-table' and 'bmp-timer' options together with the 'bitmap' option are stored in the special LILO header of the bitmap image file by the lilo -E command. Another way works without these special header information: All the information about 'bmp-colors', 'bmp-table' and 'bmp-timer' options together with the 'bitmap' option are stored in the configuration file. Any use of the 'bmp-' options within the configuration file overrides the options stored in the bitmap file header. If lilo cannot find any of the 'bmp-' options, then default values are used.

bmp-colors=<fg>,<bg>,<sh>,<hfg>,<hbg>,<hsh>

Specifies the decimal values of the colors to be used for the menu display on a 'bitmap=' background. The list consists of 6 entries, 3 for normal text followed by 3 for highlighted text. The order of each triple is: foreground color, background color, shadow color. If background color is not specified, "transparent" is assumed. If shadow color is not specified, then "none" is assumed. The list entries are separated by commas, with no spaces.

bmp-retain

Option applies to all 'image=' and 'other=' sections. (See COMMON OPTIONS, below.)

bmp-table=<x>,<y>,<ncol>,<nrow>,<xsep>,<spill>

Specifies the location and layout of the menu table. <x>,<y> specify the starting x- and y-position of the upper left corner of the table in character coordinates: x in [1..80], y in [1..30]. <ncol> is the number of columns in the menu (1..5); and <nrow> is the number of rows (entries) in each column. If more than one column is specified, then <xsep> is the number of character columns between the leftmost characters in each column: (18..40), and <spill> is the number of entries in one column which must be filled before entries spill into the next column. <spill> must be .le. <nrow>. If pixel addressing is used, instead of character addressing, then any of <x>, <y>, or <xsep> may be specified with a 'p' suffix on the decimal value.

bmp-timer=<x>,<y>,<fg>,<bg>,<sh>

Optional specification of the 'timeout=' countdown timer. <x>,<y> specifies the character (or pixel) coordinate of the location of the timer the same as 'bmp-table=' above; and the color triple specifies the character color attributes the same as 'bmp-colors=' above, with the exception that the background color must be specified. If used to override the timer specification in a bitmap file, then the form 'bmp-timer = none' is acceptable. This will disable the timer display entirely.

boot=<boot-device>

Sets the name of the device (e.g. hard disk or partition) that contains the boot sector and where the new boot sector should be written to. Notice: The boot-device should be the device with the currently mounted root partition.

A raid installation is initiated by specifying a RAID1 device as the boot device; e.g., "boot=/dev/md0".

On newer systems you need an unique ID for the boot device. If the boot sector should write to a partition you can use its UUID in the same manner is for the root options.

If your boot device is a hard disk you need a special ID, which is supported by udev. You find the right ID in the directory /dev/disks/by-id, i. e.:

    boot = /dev/disk/by-id/ata-SAMSUNG_SV1604N_S01FJ10X999999

change-rules

Defines boot-time changes to partition type numbers (`hiding').

change-rules
   reset
   type=DOS12
      normal=1
      hidden=0x11
   type=DOS16_small
      normal=4
      hidden=0x14
   type=DOS16_big
      normal=0x06
      hidden=0x16

The above excerpt from a configuration file specifies that all default change-rules are removed ("reset"), and the change-rules for three partition types are specified. Without the reset, the three types specified would have been added to the existing default change-rules. Normally, the default rules are sufficient. The strings which define the partition types are used in a change section (see below), with the suffixes "_normal" or "_hidden" appended. See section "Partition type change rules" of html/user_21-5.html inside the old documentation for more details.

compact

Tries to merge read requests for adjacent sectors into a single read request. This drastically reduces load time and keeps the map file smaller. Using `compact' is especially recommended when booting using a map file on a floppy disk.

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. See also, vmdefault below.

delay=<tsecs>

Specifies the number of tenths of a second the boot loader should wait before automatically booting a locked command line, a command line pre-stored by "lilo -R", or the default `image=' or `other='. When `delay' is non-zero, the boot loader will wait for an interrupt for the specified interval. If an interrupt is received, or is already waiting, the boot: prompt will be be issued, and no automatic boot will take place. The setting of CAPS LOCK or SCROLL LOCK, or any of the keys ALT, CTRL, or SHIFT, when held down, are taken as interrupts.
This action is modified by specifying `prompt' (see below).

disk=<device-name>

Defines non-standard parameters for the specified disk. See section "Disk geometry" of html/user_21-5.html inside the old documentation for details. For versions of LILO prior to 22.5, the `bios=' parameter is quite useful for specifying how the BIOS has assigned device codes to your disks. For example,

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

would say that your SCSI disk is the first BIOS disk (0x80), that your (primary master) IDE disk is the second BIOS disk (0x81), and that your second SCSI disk (perhaps a USB device) receives no device code, and is therefore inaccessible at boot time.

NOTE: Use of the 'bios=' option is largely obsolete beginning with LILO version 22.5, as the boot loader now identifies disks by 32-bit Volume-ID, and defers BIOS device code determination until boot time.

Other options include the specification of disk geometry; e.g.,

       disk=/dev/fd0
            sectors=18
            heads=2
            cylinders=80

probably only useful for floppy disks and loopback devices, because for hard disks the lba32 disk addressing option ignores disk geometry.

Developers who have implemented a disk driver for a new block storage device will have to indicate to LILO the maximum number of partitions on the device. This is in addition to making all of the necessary entries for the device in the "/dev" directory (with 'mknod'). The maximum number of partitions must be one of 63 (like an IDE disk), 31 (uncommon), 15 (like SCSI disks -- most common value), or 7 (like one array controller). An example specification would be:

     disk=/dev/userd0
          max-partitions=15

In cases where there is no kernel partition information available, such as on loopback devices, the 'disk=' specification may include paritition start information; viz.,

       disk=/dev/loop0
            bios=0x80                   # use this BIOS code
            max-partitions=7            # declare partitionable
            paritition=/dev/loop1
                 start=63               # offset from sector 0
            paritition=/dev/loop2
                 start=102400           # offset from sector 0

disktab=<disktab-file>

Specifies the name of the disk parameter table. The map installer looks for /etc/disktab if `disktab' is omitted. The use of disktabs is discouraged.

el-torito-bootable-CD

Flag second stage loader to terminate disk emulation when booting from an El Torito Bootable CD. This option is used by the mkrescue utility when the "--iso" switch is specified.

fix-table

This allows lilo to adjust 3D addresses in partition tables. Each partition entry contains a 3D (cylinder/head/sector) and a linear 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) 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>

Operation is identical to backup= above, except an existing backup file is unconditionally overwritten if it exists.

geometric

Force disk addressing which is compatible with older versions of LILO. Geometric addressing uses cylinder/head/sector addresses, and is limited to disk cylinders up to 1023. If inaccessible cylinders are referenced, diagnostics will be issued at boot-install time, rather than boot-time. With a newer BIOS, use of 'lba32' is recommended.

ignore-table

tells lilo to ignore corrupt partition tables.

install=<user-interface>

Selects the user interface which will be seen at boot time. One of the following three options may be specified: text, menu, or bmp. The traditional LILO interface is `text'; but `menu' is now the default, unless the configuration file contains the `bitmap=' specification. The text interface is strictly a command-line interface as though the console were a dumb terminal. The menu interface is a text-based screen of the boot choices, with the option to enter additional command line parameters. And the bmp interface is a menu presented against a graphic screen, specified as a 640x480 BitMaP file of 16 or 256 colors. (See the 'lilo -E' switch for editing options).

(Prior to LILO version 22.3, `install=' specified the user interface as a file in the `/boot' directory.)

large-memory

Normally any initial ramdisk (initrd) loaded with a kernel is loaded as high in memory as possible, but never above 15Mb. This is due to a BIOS limitation on older systems. On newer systems, this option enables using memory above 15Mb (up to a kernel imposed limit, around 768Mb) for passing the initrd to the kernel. The presence of this option merely indicates that your system does not have the old BIOS limitation.
This switch (or its absence) is not passed to the kernel, and does not in any way affect the amount of physical memory which it will use. (See the kernel documentation for the kernel command line parameter "mem=" for limiting the memory used by the kernel.)

lba32

Generate 32-bit Logical Block Addresses instead of cylinder/head/sector 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 cylinder/head/sector ('geometric'), 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. Beginning with LILO version 22, 'lba32' is the default disk addressing scheme.

linear

Generate 24-bit linear sector addresses instead of cylinder/head/sector (geometric) addresses. Linear addresses are translated at run time to geometric addresses, and are limited to cylinders <= 1023. When using `linear' with large disks, /sbin/lilo may generate references to inaccessible disk cylinders. 'lba32' avoids many of these pitfalls with its use of packet addressing, but requires a recent BIOS (post-1998). The 'linear' option is considered obsolete, and its use is strongly discouraged.

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.

mandatory

The per-image password option `mandatory' (see below) applies to all images.

map=<map-file>

Specifies the location of the map file. If `map' is omitted, the file /boot/map is used.
On machines with a pre-1998 BIOS, the EDD bios extensions which are required to support "lba32" disk sector addressing may not be present. In this case, the boot-loader will fall back automatically to "geometric" addressing; this fall back situation, or the specific use of "geometric" or "linear" addressing, will require the map file to be located within the first 1024 cylinders of the disk drive. This BIOS limitation is not present on post-1998 systems, most of which support the newer EDD disk BIOS calls.

menu-title=<title-string>

Specifies the title line (up to 37 characters) for the boot menu. This title replaces the default "LILO Boot Menu" title string. If menu is not installed as the boot loader (see install= option), then this line has no effect.

menu-scheme=<color-scheme>

The default color scheme of the boot menu may be overridden on VGA displays using this option. (The color scheme of MDA displays is fixed.) The general color-scheme string is of the form:

     <text>:<highlight>:<border>:<title>

where each entry is two characters which specify a foreground color and a background color. Only the first entry is required. The default highlight is the reverse of the text color; and the default border and title colors are the text color. Colors are specified using the characters kbgcrmyw, for blacK, Blue, Green, Cyan, Red, Magenta, Yellow, and White: upper case for intense (fg only), lower case for dim. Legal color-scheme strings would be

    menu-scheme=Wm     intense white on magenta
    menu-scheme=wr:bw:wr:Yr    the LILO default
    menu-scheme=Yk:kw    bright yellow on black

If menu is not installed as the boot loader, then this line has no effect.

message=<message-file>

specifies a file containing a message that is displayed before the boot prompt. No message is displayed while waiting for a shifting key after printing "LILO ". In the message, the FF character ([Ctrl L]) clears the local screen. This is undesirable when the menu boot loader is installed. 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. 'message=' and 'bitmap=' are mutually exclusive.

nodevcache

(22.8) Disables pre-loading of the internal device cache. May be needed for Linux distributions which use non-standard device naming conventions; e.g., when the first IDE disk is not `/dev/hda'.

nokbdefault=<name>

(22.7.2) The named descriptor is taken to be the default boot image if no IBM-PC keyboard is present. If no serial interface ("serial=") is in use, then any "prompt" keyword and "timeout" value are bypassed, and default booting occurs as specified by "delay=". The keyboard detection codes cannot detect the presence or absence of a newer USB keyboard.

noraid

Disables the automatic marking of disk volumes which are components of RAID arrays as inaccessible. This allows the user to edit the disk= / inaccessible declarations into the configuration file himself. Without such declarations, duplicate Volume IDs will be overwritten, leading to confusing situations at boot-time, and possible failure to boot. The use of this keyword is generally not necessary.

nowarn

Disables warnings about possible future dangers.

optional

The per-image option `optional' (see below) applies to all images.

password=<password>

The per-image option `password=...' (see below) applies to all images. This option may prevent unattended booting, if the default image is `password=' protected at the default level `mandatory', which is a level higher than `restricted'.

prompt

Automatic booting (see `delay' above) will not take place unless a locked or pre-stored ("lilo -R") command line is present. Instead, the boot loader will issue the boot: prompt and wait for user input before proceeding (see timeout below). Unattended default image reboots are impossible if `prompt' is set and `timeout' is not, or the default image is password protected at a higher level than `restricted'.

raid-extra-boot=<option>

This option only has meaning for RAID1 installations. The <option> may be specified as none, auto, mbr, mbr-only, or a comma-separated list of devices; e.g., "/dev/hda,/dev/hdc6". Starting with LILO version 22.0, the boot record is normally written to the first sector of the RAID1 partition. On PARALLEL raid sets, no other boot records are needed. The default action is auto, meaning, automatically generate auxiliary boot records as needed on SKEWED raid sets. none means suppress generation of all auxiliary boot records. mbr-only suppresses generation of a boot record on the raid device, and forces compatibility with versions of LILO earlier than version 22.0 by writing boot records to all Master Boot Records (MBRs) of all disks which have partitions in the raid set. mbr is like mbr-only except the boot record on the RAID partition is not suppressed. Use of an explicit list of devices, forces writing of auxiliary boot records only on those devices enumerated, in addition to the boot record on the RAID1 device. Since the version 22 RAID1 codes will never automatically write a boot record on the MBR of device 0x80, if such a boot record is desired, this is one way to have it written. Use of mbr is the other way to force writing to the MBR of device 0x80.

restricted

The per-image password option `restricted' (see below) applies to all images.

serial=<parameters>

enables control from a serial line. The specified serial port is initialized and the boot loader 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 the boot loader'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>]]]

<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, 150, 300, 600, 1200, 2400(default), 4800, 9600, plus the extended rates 19200, 38400, and 57600(56000). 115200 is allowed, but may not work with all COMx port hardware.

<parity>: the parity used on the serial line. The boot loader 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.

single-key

This option specifies that boot images or 'other's are to be selected and launched with a single keystroke. Selection is based upon the first character of each name, which must be unique. This option should not be used with the menu or bitmap user interface ("install=").

static-BIOS-codes

Causes the operation of the boot installer and boot loader to bypass the use of Volume-ID information, and to revert to a mode of operation of versions of LILO from 22.4 backward. With Volume-ID booting (22.5 and later), the BIOS codes of disks are determined at boot time, not install time; hence they may be switched around, either by adding or removing disk(s) from the hardware configuration, or by using a BIOS menu to select the boot device.

With the use of this option, BIOS codes of disks MUST be correctly specified at install time; either guessed correctly by LILO (which often fails on mixed IDE/SCSI systems), or explicitly specified with 'disk=/dev/XXX bios=0xYY' statements. The use of this option precludes any activity which may switch around the BIOS codes assigned to particular disk devices, as noted above.

In general, this option should never be used, except as a bug workaround.

suppress-boot-time-BIOS-data

This global option suppresses the boot-time real mode collection of BIOS data on systems which hang on certain BIOS calls. It is equivalent to using the boot-time switch 'nobd'.

This option defeats the disk volume recognition and BIOS device code detection features of LILO on systems with more than one disk. Thus the use of this option will produce a strong cautionary message, which cannot be suppressed.

timeout=<tsecs>

sets a timeout (in tenths of a second) for keyboard input at the boot: prompt. "timeout" only has meaning if "prompt" is mentioned. If no key is pressed for the specified time, the default image is automatically booted. The default timeout is infinite.

unattended

(22.6) Alters the operation of the "timeout" parameter in a manner which is useful on noisy serial lines. Each typed (or noise) character restarts the "timeout" timer and a timeout will always boot the default descriptor, even if noise characters have appeared on the input line.

verbose=<number>

Turns on lots of progress reporting. Higher numbers give more verbose output. If -v is additionally specified on the lilo command line, the level is increased accordingly. The maximum verbosity level is 5.

vmdefault=<name>

The named boot image is used as the default boot if booting in "virtual" mode with a virtual monitor, such as VMware(tm). Thus a real mode boot and a virtual mode boot can be made to have different default boot images.

Additionally, the kernel configuration parameters append, ramdisk, read-only, read-write, root and vga 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 kernel images.

PER-IMAGE SECTION

A per-image section starts with either a line

    image=<pathname>

to indicate a file or device containing the boot image of a Linux kernel, or a line

    other=<device>

to indicate an arbitrary system to boot.

In the former case, if an image line specifies booting from a device, then one has to indicate the range of sectors to be mapped using

    range=<start>-<end>
    range=<start>+<nsec>
    range=<sector>

In the third case, 'nsec=1' is assumed.

KERNEL OPTIONS (image=)

If the booted image is a Linux kernel, then one may pass command line parameters to this kernel.

addappend=<string>

The kernel parameters of this string are concatenated to the parameter(s) from an append= option (see below). The string of addappend must be enclosed within double quotes. Usually, the previous append= will set parameters common to all kernels by appearing in the global section of the configuration file and addappend= will be used to add local parameter(s) to an individual image. The addappend option may be used only once per "image=" section.

If the string is a very long line, this line can be divided in more lines using "\" as last character of a line, e.g.

    addappend="noapic acpi=off pci=usepirqmask \
            pnpbios=off pnpacpi=off noisapnp"

append=<string>

Appends the options specified to the parameter line passed to the kernel. This is typically used to specify hardware parameters that can't be entirely auto-detected or for which probing may be dangerous. Multiple kernel parameters are separated by a blank space, and the string must be enclosed in double quotes. A local append= appearing within an image= section overrides any global append= appearing in the global section of the configuration file. The append option may be used only once per "image=" section. To concatenate parameter strings, use "addappend=". Example:

     append="mem=96M hd=576,64,32 console=ttyS1,9600"

If the string is a very long line, this line can be divided in more lines using "\" as last character of a line. See example of addappend option.

initrd=<name>

Specifies the initial ramdisk image to be loaded with the kernel. The image will contain modules needed at boot time, such as network and scsi drivers. See man pages for mkinitrd(8).

literal=<string>

Like `append', but removes all other options (e.g. setting of the root device). 'literal' overrides all 'append' and 'addappend' options. Because vital options can be removed unintentionally with `literal', this option cannot be set in the global options section.

ramdisk=<size>

This specifies the size (e.g., "4096k") 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

This specifies that the root file system should be mounted read-only. It may be specified as a global option. Typically, the system startup procedure re-mounts the root file system read-write later (e.g. after fsck'ing it).

read-write

This specifies that the root file system should be mounted read-write. It may be specified as a global option.

root=<root-device>

This specifies the device that should be mounted as root. It may be specified as a global option. 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 running kernel image is used. Warning: This can induce to an unbootable system!

The root filesystem may also be specified by a LABEL= or UUID= directive, as in '/etc/fstab'. In this case, the argument to root= must be enclosed in quotation marks, to avoid a syntax error on the second equal sign, e.g.:

     root="LABEL=MyDisk"
     root="UUID=5472fd8e-9089-4256-bcaa-ceab4f01a439"

Note: The command line root= parameter passed to the kernel will be: 'root=LABEL=MyDisk'; i.e., without the quotation marks. If the root= parameter is passed from the boot time boot: prompt, no quotes are used. The quotes are only there to satisfy the requirements of the boot-installer parser, which treats an equal sign as an operator. The kernel command line parser is very much simpler, and must not see any quotation marks. Simply stated, only use the quotation marks within /etc/lilo.conf.

vga=<mode>

This specifies the VGA text mode that should be selected when booting. It may be specified as a global option. The following values are recognized (case is ignored):

normal: select normal 80x25 text mode.

extended (or ext): select 80x50 text mode.

ask: stop and ask for user input (at boot time).

<number>: use the corresponding text mode (can specify the number in decimal or in hex with the usual '0x' convention). 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. (And that is set at compile time using the SVGA_MODE variable in the kernel Makefile, and can later be changed with the rdev(8) program.)

ALTERNATE SYSTEM (other=)

Used to load systems other than Linux. The `other = <device>' specifies the boot sector of an alternate system contained on a device or disk partition; e.g., DOS on, say, `/dev/hda2', or a floppy on `/dev/fd0'. In the case of booting another system there are these options:

loader=<chain-loader>

This specifies the chain loader that should be used. It may also be specified as a global option. By default chain is used. This chain loader passes partition and drive information in the boot sector it loads only to DOS on FAT12 or FAT16, Windows on FAT16 or FAT32. (see also table=<letter> below).

table=<device>

This specifies the device that contains the partition table. The boot loader will pass default 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.

change

This keyword starts a section which describes how primary partition IDs are changed, and how primary partitions are activated and deactivated. If change is omitted, change rules are generated as though the automatic keyword were specified. The keyword change alone, without any rules following, will suppress automatic change-rules. For example,

   other=/dev/hda2
      label=dos
      table=/dev/hda
      change
        automatic
        partition=/dev/hda1
           set=DOS12_hidden
           deactivate
        partition=/dev/hda2
           set=DOS16_big_normal
           activate

specifies that when primary partition /dev/hda2 is booted, automatic change-rules will be in effect; plus, partition 1, a DOS12 partition, will be set hidden, and deactivated. In addition, partition 2, will be set normal, and activated. Activation sets the boot-flag in the partition table. The automatic keyword may conflict with default change rules, so the set= lines above may be redundant.

boot-as=<bios>

This option (LILO version 22.5.1) indicates the BIOS device code which must be assigned to the specified drive in order for the "other=" operating system to boot. If the chain loader detects that another BIOS device code is assigned to this disk, then it will dynamically swap the assigned device code with the specified device code.

This option is easier to specify than "map-drive=" and more general than "master-boot" in that any device code may be specified. Unlike "map-drive=", the determination whether to swap device codes is made at boot time, not install time. This is advantageous on systems where the BIOS presents a boot menu of devices, and will map disks to devices in different ways, depending upon the BIOS boot selection.

This option may be specified as a global option, in which case it applies to all "other=" sections unless overridden with a specific "master-boot" option. If one of "boot-as=" or "master-boot" is specified as a global option, it is better to specify "master-boot" as the global option, as it will not interfere with floppy disk BIOS device codes; "boot-as=" is then used as a local option to override "master-boot" as necessary.

master-boot

This flag (LILO version 22.5) indicates a DOS/Windows or other system which will only boot from BIOS device 0x80, the "C:" drive, or BIOS device 0, the A: drive. When this flag is specified, if this drive is not assigned device code 0x80 or 0 by the BIOS, then the chain loader will dynamically swap the device code actually assigned with device code 0x80 or 0 to make this drive appear to be the first hard or floppy drive, "C:" or "A:".

This flag is easier to use than "map-drive=" (see below), and is preferred, if simple forcing of device code 0x80 is all that is required. It is also more general, in that the necessity to swap BIOS device codes is determined dynamically at boot-time, not at boot install-time, as with "map-drive=". It is slightly more powerful than "boot-as=", in that the device code which is assigned, 0 or 0x80, is determined dynamically.

This option may be specified as a global option, in which case it applies to all "other=" sections unless overridden with a specific "boot-as=" option.

map-drive=<num>

Maps BIOS calls for the specified drive to the device code specified on the next line as to=<num>. This mapping is useful for booting operating systems, such as DOS, from the second hard drive. The following, swaps the C: and D: drives,

   map-drive=0x80
      to=0x81
   map-drive=0x81
      to=0x80

This option is largely rendered obsolete by "boot-as=", introduced with LILO version 22.5.

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. If the boot sector is on a hard drive, the BIOS device code of the drive will have to be specified explicitly with "disk=/dev/XXXX bios=0x8X inaccessible" in the configuration file. `unsafe' and `table' (explicit or implicit) are mutually incompatible.

COMMON DESCRIPTOR OPTIONS (image= & other=)

In both the image= and other= cases, the following options apply.

bypass

No password is required to boot this image. Used to indicate that the global password does not apply to this `image=' or `other='. See 'password=' below.

label=<name>

The boot loader 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'.

alias=<name>

A second name for the same entry can be used by specifying an alias.

bmp-retain

The bitmap graphic (install=bmp) is retained when control is passed to the loaded kernel image, or other= bootloader; i.e., the screen is not blanked to alphanumeric mode before starting the kernel. This feature is considered EXPERIMENTAL, for those users working with startup splash screens.

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 stored by the fallback mechanism is cleared by removing or changing the default command line with the -R option, which should be a part of the boot startup scripts.

lock

(See above.)

optional

Omit the image if it is not available at map creation time. It may be specified as a global option. This is useful to specify test kernels that are not always present.

password=<password>

Protect the `image=' or `other=' with a password (or passphrase). It may be specified as a global option. The interpretation of the `password=' setting is modified by the words `mandatory', `restricted', and `bypass' (see below).
The password may be specified in the config-file (less secure) or entered at the time the boot loader is installed. To request interactive entry of the password, it should be specified: password="". Passwords entered interactively are not required to be entered again if the boot installer is re-run. They are cached, in hashed form, in a companion file to the config-file, default name: /etc/lilo.conf.crc. If the config-file is updated, a warning message will be issued telling you to re-run lilo -p to force re-creation of the password cache file.

mandatory

A password is required to boot this image. This is the default. May be used on a single `image=' or `other=' to override a different global setting.

nokbdisable

(22.7.2) The specified descriptor is not bootable if the IBM-PC keyboard is not present. This option is really only useful if the "serial=" boot terminal is in use. With no keyboard (and no serial terminal) attached, selecting a boot descriptor other than the default is impossible. See nokbdefault above.

restricted

A password is only required to boot the image if kernel parameters are specified on the command line (e.g. 'single'). May be used on a single `image=' or `other=' to override a different global setting.

vmwarn

If booting under a virtual monitor such as VMware(tm), the image with this label will cause a cautionary warning to be issued at boot time, and user intervention will be required to continue or to abort the boot process.

vmdisable

If booting under a virtual monitor, the image with this label will not be displayed as a boot option. The image is only bootable in real mode. See vmdefault above.

SEE ALSO

lilo(8), mkinitrd(8), mknod(1), mkrescue(8), rdev(8).