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Re: [OCLUG-Tech] linux install with kernel parameters

  • Subject: Re: [OCLUG-Tech] linux install with kernel parameters
  • From: "Alex @ Avantel Systems" <ahv [ at ] avantel [ dot ] ca>
  • Date: Wed, 5 Oct 2005 21:55:54 -0400
Thanks for responding - see below

On Wednesday 05 October 2005 19:00, Peter Sjoberg wrote:
> On Wed, 2005-10-05 at 17:59 -0400, Alex @ Avantel Systems wrote:
> > On Wednesday 05 October 2005 17:31, you wrote:
> > > On Wed, Oct 05, 2005 at 12:13:47AM -0400, Alex @ Avantel Systems wrote:
> > > > [...]
> > > > At that point the system complains that no operating system was
> > > > found. I'm assuming that the disks are not found because if I use
> > > > linux rescue, the disks can't be found and the installer can't find
> > > > any trace of the bootloader.
> > >
> > > "No operating system found" usually means that the BIOS can't find a
> > > bootable OS.  GRUB hasn't even entered the picture at this point.  Are
> > > you sure your BIOS can boot off this drive?
> >
> > Yes - I had it working with RH7.2 and was able to do that with a default
> > install.
> >
> > Isn't there a step in between - initrd - which loads the drivers needed
> > to access the disk?  If the correct drivers aren't available the disks
> > can't be seen.
>
> Simplified you can say that
>  Bios scans disks
>  Bios decided what disk to boot from
>  Bios loads the MBR from the disk
>  CPU jumps to the bootstrap loader in the MBR where it finds GRUB
>   grub starts it's stuff and boots os
>
>   Since it worked before the scan disk part should be ok
>   If the Bios can't find a valid MBR on the disk it normally stops with
> "no os found" (and the original IBM PC did jump to ROM BASIC).
>   If the MBR is ok then grub starts but if Grub can't find the menu it
> will stop at a prompt, not a "OS not found" message.

The message I get is ;

Operating System not found

>   If you are using LILO it will start printing out L I L O and if it
> fails it stops, a little like an error code. If it just prints LI (the
> most common problem) it can't find the kernel, probably because you
> moved the file on the disk.

I'm using grub

>
> Exactly what message do you see ? The message may vary depending on the
> bios flavour and another possibility is that you somehow use an old MS
> disk where the MBR still is intact. If that's the case it will go on to
> the MBR but when it fails to find MSDOS.SYS it prints out something like
> "no os found".

Hmmm -that's close to what I get - how would I confirm that the old MBR is 
still intact (more below)
>
> Assuming it was a problem for grub to write down the MBR in the right
> place you can fix that from rescue but exactly how depends a little on
> why it failed.
>
> What dos /boot/grub/device.map look like ?
> Should at least contain
>
> (hd0) /dev/sda

Yes, that and the equivalent for the floppy

>
> If so you should be able to do something like
>
> grub --device-map=/boot/grub/device.map --batch <<EOF
> install (hd0,0)/boot/grub/stage1 d (hd0) (hd0,0)/boot/grub/stage2 p
> (hd0,0)/boot/grub/menu.lst quit
> EOF

OK did that and success was claimed but I'm not convinced . . . been there 
before with raid problems.  

>
> to write a good MBR.
>
> > The default install couldn't see the disks either - I had to load the
> > modules manually and then the install was able to complete OK.
> >
> > Assuming that some specific modules are needed to see the disks, how do I
> > fix that?  I'm assuming I need a different set of drivers in initrd but
> > how do I get there from here?
>
> mkinitrd /boot/initrd-$(uname -r).img $(uname -r)
> You may have to add  "--with=the_module_you_loaded" to get it right

Tried that too, also with;

"--with=aic7xxx" and also tried
"--preload=aic7xxx" with and without
"--onit-raid-modules"

Also tried using a boot floppy by copying stage 1&2 .  That just gave me the 
grub prompt.

I feel like I'm really close to solving this yet I'm just as far as when I 
started - can't boot.

Any Ideas?

TIA

Alex
====

>
> > Alex
> > ====
> >
> > > I don't really know what to suggest though.  One workaround if you have
> > > a floppy drive is to always use a boot disk, but since the Fedora disks
> > > don't detect your disks automatically, you'll probably need to create
> > > one by hand.  If you're familiar with compiling kernels, 'make zdisk'
> > > is one way to go.
> > >
> > > Good luck!
> > > Jody
>
> --
> -------------------------------------------------------------------
> Techwiz, Peter Sjoberg    PGP key (12F506C8) on keyserver & homepage
> Key fingerprint =  3DC2 CEBA 1590 B41A 3780  955A DB42 02BB 12F5 06C8
> mailto:peters AT techwiz.ca http://www.techwiz.ca/~peters

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