Re: boot ext2 on vfat

Hi mammique,

On Thu, Mar 18, 2004 at 21:02:54 +0100, mammique wrote:

> i'd like to know if it's possible, if anybody thought/tried, to boot
> from a virtual ext2 partition (containing the system) wich is file on
> vfat ? The file could be created from a knoppix-cd during HD

It is possible. I just did a quick and dirty hack on an older version
of knx-hdinstall. I hardcoded the parts for creating and mounting
the ext2 container file (knx.img). After the file copying step, you must
change the rootfs fstab entry to:
/dev/loop0  /  ext2  defaults,errors=remount-ro  0  1

The tricky part is the initial ramdisk. It must mount the vfat
partition first, then assign the ext2 container file to /dev/loop0
and tell the kernel to use /dev/loop0 as root device:

#!/bin/sh
# this is /linuxrc
insmod /modules/loop.o
mount -t vfat /dev/hda1 /mnt/dosfs
# use knx.img for loop0
losetup /dev/loop0 /mnt/dosfs/knx.img
mount -t proc proc /proc
# 1792 = 7*256+0 = loop0
echo 1792 > /proc/sys/kernel/real-root-dev
umount /proc

Kernel and initrd must be loaded off the vfat partition by loadlin.exe
running in real dos mode. Note that this is only possible when using
Win95/98/ME.

WinNT/2k/XP do not have real dos mode, so loadlin.exe cannot run.

bye,
  Chris
-- 
Christian Perle                                    chris AT linuxinfotag.de
Grunaer Str. 31                                    http://silmor.de/~chris/
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