Re: [gentoo-user] Boot situation

[Alan McKinnon]

On Sunday 09 September 2007, Colleen Beamer wrote:
> Hi all,
>
> Please read this carefully.  Don't take offense, I'm not insinuating
> that you wouldn't.  It's just that I don't want to get myself into
> more of a pickle than I'm in!  ;-(

Nah, hit the right buttons in the right order at the right time and you 
can fix anything :-)


I'll give you a verbose reply in the hopes that we can get to the root 
of the problem right away

> This morning as I was getting my son off to work, he got me upset
> about something and I walked over to my laptop and instead of hitting
> the 'On' button, I accidentally hit the 'Media Direct' button.  (I'm
> explaining the why so you won't thing that I'm a total airhead!).
> The laptop is a Dell XPS M1710.  The Dell Media Direct Splash screen
> display, but of course, did nothing else 'cause there is only Linux
> on the laptop.

I'm not familiar with that 'Media Direct' thing, no Dell I've ever 
worked on has such a thing. Can you fill me in on what it does, so we 
can try figure out what dastardly thing it did to your system?


> Anyway, this corrupted my boot partition, but I was able to fix that.
>  I just deleted the partition that hitting the 'Media Direct' button
> made. It put this at the end of the hard drive, but it was made the
> bootable partition and had a DOS/Windows partition type.

bootable partition markers are ignored under Linux, they make no real 
sense with a real boot loader like grub.

The Media Direct making a partition and you deleting it should not 
affect anything. It's a lot like creating a file - it doesn;t affect 
the existing files. Unless of course the Media Direct trashed an 
existing partition, which no sane software should ever do.

> I deleted the partition that hitting the 'Media Direct' button had
> made, then recreated a new Linux partition with an ext2 file system
> and made this bootable where the original boot partition had been.

OK. That's the long way round but it seems like you got it fixed anyway. 
I find it to be a good idea to keep a spare copy of the files in /boot 
for cases like this - saves having to recompile the kernel

> Then, I followed the Gentoo Handbook, doing all the relevant steps
> except for downloading software that was already there.  I chroot'd
> into my environment to install grub - I did all the relevant steps
> including chrooting into my own environment.  In my chroot'd
> environment, I can do an 'ls' and it reads the drives.  I can also
> edit files like grub.conf and fstab, so there isn't a problem with my
> remaining partitions after reconfiguring the boot partition.
>
> I reinstalled grub, created grub.conf and ran grub-install and that
> was successful.
>
> However, when I reboot, I get a garbled screen, but I *can* make out
> the text, although barely.

Thats tells me the grub install did not in fact go right. But no matter, 
it seems to work so once we get the OS running, we can fix the grub 
later. Meanwhile just remember that you have to navigate grub blind 
when booting

> It goes through the boot process and gets to the point where
> 'Activating mdev' is displayed
>
> Then, the following is displayed:
> Determining root device
> Block dev sda3 is not a valid root device
> The root block device is unspecified or not detected.

That is the root of your problem and is one of two things:

/dev/sda3 is corrupt, or
/dev/sda3 is nto the partition you boot from and grub.conf is corrupt

> Of note and I'm not sure if this is where the problem is, is that
> when I was mounting my partitions prior to chroot'ing into my own
> environment, I got a message about maximal mount count and it told me
> I should run e2fsck.  I tried this and got an error message.
> However, my hard drive is not ext2, it is ext3.

That's normal. ext2 does a file system check every 20 or so mounts as a 
safety feature, and this time just happened to be your turn. e2fsck 
willnormally do it's thing as exit without having to do anything. This 
is good, as you don't expect the filesystem to be damaged normally, and 
it's good to see that they are in fact intact.

That you use ext3 is also not relevant - ext3 is a new! improved! ext2 
with one awesomely useful extra feature. Any tool necessary on ext2 
still works on ext3.

> I apologize for the length of this, but I wanted to try to explain
> everything.  I'm having fits here - I'm writing from my old 686
> computer which did have all my files on it.  However, I ftp'd them to
> my webspace and then back down to the laptop.  When I did that, I
> deleted most of them off the 686 and as luck would have it I didn't
> do a recent backup from the laptop.  I do have an older backup, but
> would lose some recent files if I can't get my laptop up and running
> without a reinstall.

I'd need some info at this point to help you further. You will likely 
need to boot off a LiveCD or rescue disk to get to this, then mount the 
root partition and chroot into it. Do you know the procedure for that?

What was your partition layout before this mistake happened? If you can 
remember how many partitions you had, their size, the order they were 
in and where they were mounted, that info would be useful.

The contents of your /etc/fstab and /boot/grub/grub.conf

The output of 'fdisk -l /dev/sda'

The output of e2fsck, run on each of your filesystems

alan


>
> Thanks in advance for your help.
>
> Regards,
>
> Colleen
> --
>
> Registered Linux User #411143 with the Linux Counter,
> http://counter.li.org



-- 
Optimists say the glass is half full,
Pessimists say the glass is half empty,
Developers say wtf is the glass twice as big as it needs to be?

Alan McKinnon
alan at linuxholdings dot co dot za
+27 82, double three seven, one nine three five
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