LILO.CONF(5)LILO.CONF(5)NAMElilo.conf - configuration file for lilo
DESCRIPTION
This file, by default /etc/lilo.conf, is read by the boot loader in‐
staller '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 user.tex from the lilo
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 configura‐
tion file. If you enter nothing, then the default kernel image, the
first mentioned, (/boot/zImage-1.5.99) will be booted after a timeout
of 15 seconds (150 deciseconds). There may be at least 16 images men‐
tioned 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 descrip‐
tions 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 lit‐
erally from user.tex (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 instal‐
lations 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 over‐
written. C.f., force-backup= below.
bios-passes-dl=<option>
The option is indicated as yes, no, or unknown. If not speci‐
fied, a value of "unknown" is assumed, unless additional infor‐
mation is available to the boot installer. When "no" is speci‐
fied, it indicates that the BIOS is known not to pass the cur‐
rent 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.
N.B.: This option may not be retained in releases beyond
22.5.1, and 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 configura‐
tion file. +Any use of the 'bmp-' options within the configura‐
tion 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, "transpar‐
ent" 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 COM‐
MON 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 char‐
acter 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 specifi‐
cation 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. a hard disk partition) that
contains the boot sector. If this keyword is omitted, the boot
sector is read from (and possibly written to) the device that is
currently mounted as root.
A raid installation is initiated by specifying a RAID1 device as
the boot device; e.g., "boot=/dev/md0". Note that LILO version
22.0 and later operate differently from earlier versions with
respect to the actual location of the boot records.
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 suffi‐
cient. 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 user.tex 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 inter‐
rupt 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 user.tex 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 avail‐
able, 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 in‐
staller 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 boot‐
ing 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 parti‐
tion. 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 circum‐
stances, it may even be unavoidable to have conflicting parti‐
tion 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 `bit‐
map=' 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 com‐
mand line parameter "mem=" for limiting the memory used by the
kernel.)
lba32 Generate 32-bit Logical Block Addresses instead of cylin‐
der/head/sector addresses. If the BIOS supports packet address‐
ing, 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 ('geo‐
metric'), 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 cylin‐
der/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 cylin‐
ders. '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 auto‐
matically 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 cylin‐
ders 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 dis‐
plays 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 undesir‐
able 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 pres‐
ence or absence of a newer USB keyboard.
noraid Disables the automatic marking of disk volumes which are compo‐
nents of RAID arrays as inaccessible. This allows the user to
edit the disk= / inaccessible declarations into the configura‐
tion 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 key‐
word 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). Unat‐
tended 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 cor‐
responds to pressing a shift key on the console in order to get
the boot loader's attention. All boot images should be pass‐
word-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 corre‐
sponds 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 par‐
ity: "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 Vol‐
ume-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 cor‐
rectly specified at install time; either guessed correctly by
LILO (which often fails on mixed IDE/SCSI systems), or explic‐
itly 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 caution‐
ary 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 men‐
tioned. 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 man‐
ner 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 con‐
figuration 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 ker‐
nel, 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>
(22.6) The kernel parameters from the specified string, are con‐
catenated to the parameter(s) from an append= specification (see
below). The string must be enclosed within double quotes. Usu‐
ally, the previous append= will specify parameters common to all
kernels by appearing in the top, or global, section of the con‐
figuration file and addappend= will be used to add local parame‐
ter(s) to an individual image. Addappend= may be used only once
per "image=" section.
append=<string>
Appends the options specified to the parameter line passed to
the kernel. This is typically used to specify hardware parame‐
ters 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 withing an image= section overrides
any global append= appearing in the top section of the configu‐
ration file. Append= may be used only once per "image=" sec‐
tion. To concatenate parameter strings, use "addappend=". Exam‐
ple:
append="mem=96M hd=576,64,32 console=ttyS1,9600"
initrd=<name>
Specifies the initial ramdisk image to be loaded with the ker‐
nel. 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 'addap‐
pend' options. Because vital options can be removed uninten‐
tionally 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 cre‐
ated. 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 cur‐
rent 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 vari‐
able `root' is omitted, the root device setting contained in the
kernel image is used. (And that is set at compile time using
the ROOT_DEV variable in the kernel Makefile, and can later be
changed with the rdev(8) program.)
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 sat‐
isfy 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 num‐
ber 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 oper‐
ating 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.
table=<drive-letter>
This option is obsolete. It were used in the special case with
the obsolete os2_d chain loader.
change This keyword starts a section which describes how primary parti‐
tion IDs are changed, and how primary partitions are activated
and deactivated. If change is omitted, change rules are gener‐
ated as though the automatic keyword were specified. The keyword
change alone, without any rules following, will suppress auto‐
matic 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, auto‐
matic 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 speci‐
fied device code.
This option is easier to specify than "map-drive=" and more gen‐
eral than "master-boot" in that any device code may be speci‐
fied. 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 speci‐
fied, 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 spec‐
ified 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=", intro‐
duced with LILO version 22.5.
unsafe Do not access the boot sector at map creation time. This dis‐
ables 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 speci‐
fied 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: pass‐
word="". 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 warn‐
ing 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 dif‐
ferent 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 parame‐
ters 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 ALSOlilo(8), mkinitrd(8), mknod(1), mkrescue(8), rdev(8).
April 2011 LILO.CONF(5)
