Re: /sbin/dinstall fails: read-only file system
This should help you understand the boot flags. My guess is that you
should change 498 to 0.
Bruce
RDEV(8) Linux Programmer's Manual RDEV(8)
NAME
rdev - query/set image root device, swap device, RAM disk
size, or video mode
SYNOPSIS
rdev [ -rsvh ] [ -o offset ] [ image [ value [ offset ] ] ]
rdev [ -o offset ] [ image [ root_device [ offset ] ] ]
swapdev [ -o offset ] [ image [ swap_device [ offset ] ] ]
ramsize [ -o offset ] [ image [ size [ offset ] ] ]
vidmode [ -o offset ] [ image [ mode [ offset ] ] ]
rootflags [ -o offset ] [ image [ flags [ offset ] ] ]
DESCRIPTION
With no arguments, rdev outputs an /etc/mtab line for the
current root file system. With no arguments, swapdev,
ramsize, vidmode, and rootflags print usage information.
In a bootable image for the Linux kernel, there are sev-
eral pairs of bytes which specify the root device, the
video mode, the size of the RAM disk, and the swap device.
These pairs of bytes, by default, begin at offset 504
(decimal) in the kernel image:
498 Root flags
(500 and 502 Reserved)
504 RAM Disk Size
506 VGA Mode
508 Root Device
(510 Boot Signature)
rdev will change these values.
Typical values for the image parameter, which is a
bootable Linux kernel image, are as follows:
/vmlinux
/vmlinux.test
/vmunix
/vmunix.test
/dev/fd0
/dev/fd1
When using the rdev, or swapdev commands, the root_device
or swap_device parameter are as follows:
/dev/hda[1-8]
/dev/hdb[1-8]
/dev/sda[1-8]
/dev/sdb[1-8]
For the ramsize command, the size parameter specifies the
size of the RAM disk in kilobytes.
For the rootflags command, the flags parameter contains
Linux 0.99 20 November 1993 1
RDEV(8) Linux Programmer's Manual RDEV(8)
extra information used when mounting root. Currently the
only effect of these flags is to force the kernel to mount
the root filesystem in readonly mode if flags is non-zero.
For the vidmode command, the mode parameter specifies the
video mode:
-3 = Prompt
-2 = Extended VGA
-1 = Normal VGA
0 = as if "0" was pressed at the prompt
1 = as if "1" was pressed at the prompt
2 = as if "2" was pressed at the prompt
n = as if "n" was pressed at the prompt
If the value is not specified, the image will be examined
to determine the current settings.
OPTIONS
-s Causes rdev to act like swapdev.
-r Causes rdev to act like ramsize.
-R Causes rdev to act like rootflags.
-v Causes rdev to act like vidmode.
-h Provides help.
BUGS
For historical reasons, there are two methods for specify-
ing alternative values for the offset.
The user interface is cumbersome, non-intuitive, and
should probably be re-written from scratch, allowing mul-
tiple kernel image parameters to be changed or examined
with a single command.
If LILO is used, rdev is no longer needed for setting the
root device and the VGA mode, since these parameters that
rdev modifies can be set from the LILO prompt during a
boot. However, rdev is still needed at this time for set-
ting the RAM disk size. Users are encouraged to find the
LILO documentation for more information, and to use LILO
when booting their systems.
AUTHORS
Originally by Werner Almesberger (almesber@nessie.cs.id.ethz.ch)
Modified by Peter MacDonald (pmacdona@sanjuan.UVic.CA)
rootflags support added by Stephen Tweedie (sct@dcs.ed.ac.uk)
Linux 0.99 20 November 1993 2
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