I can't believe I can't find anyone else who has this problem. I have Kubuntu Gutsy installed on a SATA hard drive and want to install Slack 12 on and IDE. I did not install LILO but wanted to try to get everything working from GRUB.

Here's the latter part of my menu.lst:

## ## End Default Options ##

title Ubuntu 7.10, kernel 2.6.22-14-generic
root (hd0,0)
kernel /boot/vmlinuz-2.6.22-14-generic root=UUID=894f28ae-79f1-489e-a0bd-c0cbdf4b9913 ro quiet splash
initrd /boot/initrd.img-2.6.22-14-generic
quiet

title Ubuntu 7.10, kernel 2.6.22-14-generic (recovery mode)
root (hd0,0)
kernel /boot/vmlinuz-2.6.22-14-generic root=UUID=894f28ae-79f1-489e-a0bd-c0cbdf4b9913 ro single
initrd /boot/initrd.img-2.6.22-14-generic

title Ubuntu 7.10, memtest86+
root (hd0,0)
kernel /boot/memtest86+.bin
quiet

title Slackware 12, kernel 2.6.21.5
root (hd1,0)
kernel /boot/vmlinuz-generic-2.6.21.5 root=/dev/hda1 ro quiet
boot
### END DEBIAN AUTOMAGIC KERNELS LIST

Here is my /etc/fstab:

# /etc/fstab: static file system information.
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc defaults 0 0
# /dev/sda1
UUID=894f28ae-79f1-489e-a0bd-c0cbdf4b9913 / ext3 nouser,defaults,errors=remount-ro,atime,auto,rw,dev,exec,suid 0 1
# /dev/sda5
UUID=2db6088a-c4b7-4529-8802-6071ff8d5d52 none swap sw 0 0
/dev/scd0 /media/cdrom0 udf,iso9660 user,atime,noauto,rw,dev,exec,suid 0 0
/dev/hda1 /media/hda auto users,noauto,atime,auto,rw,nodev,noexec,nosuid 0 0

I've been reading about GRUB all day and I can't figure out what I'm doing wrong. I choose Slackware from the GRUB list when I boot up and get this:

Kernel panic-not syncing: VFS: Unable to mount root fs on unknown-block(3,1)

Any ideas?

With a generic kernel you need an initial ramdisk (initrd). You'll want to boot into a slackware huge kernel, then from there use mkinitrd to make one. I'm not sure exactly sure how to do this as I use my own custom kernel (which is another possible solution for you).

man mkinitrd or man initrd

There is a readme for creating initrd in /boot

If your filesystem is not ext3, the easiest thing to do is either boot into the huge kernel or make an initrd.

Got it. Changed my menu.lst file to the huge kernel and it booted right up! Is it because the generic kernel is not loading needed modules and the huge kernel does?

I really appreciate all your replies. Now I'm going to have some fun breaking this box over and over!

Go to boot and run

Then add

to menu.lst and you ought to be able to boot the generic kernel

The huge kernel contains almost everything (including the filesystem) in the kernel itself (hence why it is 'huge'). The generic kernel contains very little within the kernel but instead provides almost everything as modules. Most modules can be automatically loaded for you and you won't have to do much. However, the filesystems are also built as modules and the system can't do anything until it can read your files, and to do that it needs to be able to access the filesystem. Therefore, you need to make an initial ramdisk (an initrd) that loads the filesystem that you use on your / partition so the system can actually boot. arubin's instructions should work perfectly (you can do that when you have booted into the system using the huge kernel). Then you can add a GRUB entry to boot Slackware using the generic kernel (I would leave an entry that boots the huge kernel though just in case you mess up your generic kernel or the initrd -- the huge kernel will almost always boot, allowing you to fix your system).

Good to see it worked. Here's my explanation for what was going on:

On boot, the kernel is loaded into RAM, but the modules are NOT. So if the kernel was not built with support for the filesystem you are using on your root '/' partition, it cannot mount the root partition and thus cannot access any modules including the one needed to mount the root partition ... a type of catch22, and the kernel panics. So, the two possible solutions are to load the modules into RAM on boot using initrd, or boot a kernel with the filesystem used on the root partition built-in rather than as a module. The generic kernel only has ext3 support built-in, while the huge kernel has support for pretty much every filesystem built-in, which makes it a good install kernel and as a backup.

> The generic kernel only has ext3 support built-in

I don't think it has. I certainly get kernel panics with the generic kernel and no initrd using ext3

really ? damn, lemme check ...

you're right, it's as a module as well ... this is odd, I could have sworn it was built-in. But then, this doesn't make sense, then this kernel is actually not bootable without an initrd, right ?

Sorry, I should have checked the config. Maybe it was the generic in SW 11.0 that had it built-in.

No. I used to run 11.0 with a kernel that I had compiled, the only difference from generic being that it had ext3 compiled in.

I think the Slackware 2.6 kernels have always been like this.

But it is little difficult to get you head round. The booting process can read the disc well enough to load the kernel or the initrd but not to load the module.