knl(8)

NAME

knl - query/set image configuration parameters

SYNOPSIS

knl    [--kernel=]image  [-f=flaglist]  [--flags=flaglist]
[--noram]     [-p]    [--prompt]    [--ram=offset]    [-r=device]
[--root=device]     [-s=device]     [--swap=device]     [-v=mode]
[--video=mode] [--help] [--version]

OPTIONS

[--kernel=]image

Selects the kernel image file of interest.

-f=flaglist --flags=flaglist

Specifies the kernel flags to be set. Currently,

only RO is implemented, which specifies that the root file system

is to be mounted read-only by default. However, for compatibility

with future additions, flags of the format Xn are also accepted,

where n is in the range from 0 to 15 inclusive, and these will

set the appropriate flag.

An option of None is also implemented to indicate

that no flags should be set, but if used, the None option must be

the only option specified.

--help

Displays a help screen, then exits.

--noram

Specifies that no ramdisk should be created by de

fault.

This option is incompatible with the --prompt and

--ram parameters.

-p --prompt

Specifies that a ramdisk should be created by de

fault, and that the kernel should prompt for the relevant disk

before loading the ramdisk image from disk.

This option is incompatible with the --noram op

tion.

--ram=offset

Specifies that a ramdisk should be created by de

fault, and the offset in the disk to the start of the ramdisk im

age. This offset may not exceed 8191 blocks.

This option is incompatible with the --noram op

tion.

-r=device --root=device

Specifies the default device to mount as the file

system root. The device can be specified as described in the

DEVICES section (below), or can be specified as NFS to indicate

that the file system root is remote NFS mounted.

-s=device --swap=device

Specifies the default device to mount as a swap

partition. See the DEVICES section (below) for further details.

--version

Displays the program version, then exits.

-v=mode --video=mode

Specifies the default video mode. See the VIDEO

MODES section (below) for further details.

DESCRIPTION

In a bootable image for the Linux kernel, there are sever

al pairs of bytes which specify various kernel options, located

at the following offsets:

496 1F0 Reserved
498 1F2 Root flags
500 1F4 Reserved
502 1F6 Swap Device
504 1F8 RAM Disk Parameters
506 1FA VGA Mode
508 1FC Root Device
510 1FE Boot Signature

knl will change or display these values.

DEVICES

Valid values for the device specification in the --root

and --swap options are as follows:

/dev/aztcd /dev/aztcd[1-255]

/dev/cdouble[0-127]
/dev/double[0-127]
/dev/fd[0-3]

/dev/flash /dev/flash[1-7]
/dev/gscd /dev/gscd[1-255]
/dev/hd[a-h] /dev/hd[a-h][1-63]
/dev/hitcd /dev/hitcd[1-255]
/dev/mcd /dev/mcd[1-255]
/dev/optcd /dev/optcd[1-255]
/dev/ram /dev/ram[0-7]
/dev/rflash /dev/rflash[1-7]
/dev/rom /dev/rom[1-7]
/dev/rrom /dev/rrom[1-7]
/dev/scd /dev/scd[1-255]
/dev/sd[a-g] /dev/sd[a-g][1-15]
/dev/sjcd /dev/sjcd[1-255]
/dev/sonycd /dev/sonycd[1-255]
/dev/xda /dev/xda[1-63]
/dev/xdb /dev/xdb[1-63]

In addition to the options listed above, /dev/ramdisc and

/dev/ramdisk are synonyms for /dev/ram0 and, additionally, Boot

can be used to specify the boot device. The /dev/ part is option

al in each case (but must NOT be prefixed to the Boot option).

In addition to the above, a general method of specifying

ANY

mented. To specify a device that is not specifically supported
(or indeed one that is supported, if it comes to that), specify

Mode-X.Y

propriate minor number.

KERNEL IMAGE SELECTION

Typical values for the --kernel option, which specifies a

bootable Linux kernel image, are as follows:

/boot/vmlinuz
/boot/vmlinuz.test
/vmlinux
/vmlinux.test
/vmunix
/vmunix.test
/dev/fd0
/dev/fd1

Any other file on the disk can be specified and, providing

it satisfies the (admittedly rather basic) criteria for being a

kernel image file, it will be accepted as such.

VIDEO MODES

Valid values for the --video option are as follows:

Ask = Prompt for the video mode to use
EVGA = Extended VGA (80x50)
VGA = Standard VGA (80x25)

0 = Mode selected by choosing '0' at the prompt.
1 = Mode selected by choosing '1' at the prompt.
2 = Mode selected by choosing '2' at the prompt.
n = Mode selected by choosing 'n' at the prompt.

Valid numeric arguments are in the range from 0 to 65499

inclusive.

ERRORS

The following errorlevels may be reported:

0 Successful completion of task.

1 Kernel image file not specified.

2 Kernel image file not found.

3 Specified file is not a kernel image.

4 Kernel image file can't be updated.

5 Kernel image file not updated correctly.

255 --help or --version specified.

WHEN USING LILO

If LILO is used, knl is no longer needed for setting the

root device and the video mode since these parameters that knl

modifies can be set from the LILO prompt during a boot.
However, knl is still needed at this time for setting the

RAM disk parameters. Users are encouraged to find the LILO docu

mentation for more information, and to use LILO when booting

their systems.

AUTHORS

The knl program and documentation was written by Riley

Williams <Riley@Williams.Name>.

It was inspired by the rdev program and documentation

originally written some time ago by Werner Almesberger <almes

ber@nessie.cs.id.ethz.ch> and modified by Peter MacDonald <pmac

dona@SanJuan.UVic.CA>, with root flags support added by Stephen

Tweedie <sct@dcs.ed.ac.uk>.

Linux 2.0 18 June 2003

KNL(8)