I compiled and installed LFS in a seperate partition on my harddisk. I have fedora core & windows xp already installed.
When i chrooted into LFS and used grub to setup boot loader. I could not. it was recognising the partition (hd0,3). I had installed LFS on /dev/hda4.

So i logged out of LFS. Created a record in FEDORA's grub config.

I restared the laptop. It booted into LFS but gave the following error.

KERNEL PANIC - not syncing : VFS : unable to mount root FS on unknown block(3,4).

Please help me.

Can you post the entries in grub.conf ?

-baruah

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You do not have a /boot partition. This means that
# all kernel and initrd paths are relative to /, eg.
# root (hd0,1)
# kernel /boot/vmlinuz-version ro root=/dev/hda2
# initrd /boot/initrd-version.img
#boot=/dev/hda
default=0
timeout=5
# Use prettier colors.
color green/black light-green/black
splashimage=(hd0,1)/boot/grub/splash.xpm.gz
hiddenmenu
title Fedora Core (2.6.11-1.1369_FC4)
root (hd0,1)
kernel /boot/vmlinuz-2.6.11-1.1369_FC4 ro root=LABEL=/1 rhgb quiet
initrd /boot/initrd-2.6.11-1.1369_FC4.img

title LFS 6.1.1
root (hd0,3)
kernel /boot/lfskernel-2.6.11.12 root=/dev/hda4

title Windows XP
rootnoverify (hd0,0)
chainloader +1

Did you compile ext2 support into the kernel?

Yes, Infact i compiled support for all available types ... ext2,ext3 etc.

I had the same problem as you do...
If i am not mistaken... You did not copy the System.map and the .config files to the /boot...
Try that...
Hope that helps...

I am faced with a similar situation, dual booting a HP pavillion laptop and getting a kernel panic.

Unable to mount root fs on unknown block (3,4)

Not sure what I am missing in the kernal. Drive and files system that I'm using are compiled in the kernel. I believe this is typically what causes an error message like this. Correct me if I am wrong.

What info do you need to help?


/boot/grub/grub.conf

default 0
timeout 30

title=gentoo linux 2.6.16-r6
root (hd0,3)
kernel /boot/linux-2.6.16-r6 root=/dev/hda4

title=windows xp
rootnoverify (hd0,0)
makeactive
chainloader +1


partition layout

windows /dev/hda1
linux /boot /dev/hda2
linux swap /dev/hda3
linux / /dev/hda4

Where and how would I copy the system.map .config files ?

after compiling the kernel (don't just compile bare kernel, use make all) it is at the dir where you build your kernel...