lilo hallucination

worker201 · Post by **worker201** » Sun Jul 01, 2007 2:20 am

Hey, I've been away in Indonesia for a long time, and now I am back. Just for my own personal "fun", I have decided to reinstall Slackware on my Thinkpad T60, and document the entire process. But today I ran into a really strange problem.

Some background: swap = sda1, root = sda2, cdrom = hda

So I had just built my 2.6.x kernel and was going to install it. After updating lilo.conf, I ran /sbin/lilo to update the bootblock. Got this strange message:

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 Fatal: VolumeID read error: sector 0 of /dev/sdb not readable

Now that's odd. There's no sdb present! Earlier today, though, there was. I had an external USB drive which I mounted to /mnt/memory to load some files. Afterwards, of course, I umounted it, and that was hours before running lilo.

After restarting the computer, though, the problem went away, lilo ran like normal, and the new kernel is alive and well.

In case you're curious, here's the relevant sections of lilo.conf:

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# Linux bootable partition config begins
#
# my kernel
#
image = /boot/vmlinuz
  root = /dev/sda2
  label = linux-2.6.17.13
  read-only
#
# Slackware default
#
image = /boot/vmlinuz-2.4.33.3
  root = /dev/sda2
  label = default
  read-only
#
# Linux bootable partition config ends

So the problem has disappeared. But I'd still like to know what has happened. Is lilo hallucinating? Is there some residual effect of mounting a drive that I should know about? Why does this affect lilo's ability to update the bootblock? Just curious.

Void Main · Post by **Void Main** » Sun Jul 01, 2007 7:49 am

This thread seems to indicate that newer versions of lilo search for drives that were available at boot time:

http://www.unixadmintalk.com/f39/lilo-f ... isk-57762/

I guess rebooting would have solved the problem like you did or you could have added an exclude line to your lilo.conf.

worker201 · Post by **worker201** » Sun Jul 01, 2007 11:38 am

Yeah, I saw that thread. Just wondering if you had any further advice. Sometimes it's good to get a second opinion.

Void Main · Post by **Void Main** » Sun Jul 01, 2007 11:43 am

I'm not sure what further advice I could give. Once you write the boot sector you don't have to do it again unless you change the kernel. If you use grub you don't even have to do it when changing kernels. So I guess the only further advice I could give would be to use grub. :) You can run into similar issues with grub and it's device.map though.