[lug] Grub configuration

[D. Stimits]

Andy Jolley wrote:

> I have a scrounged PC with SCSI HD and CD, and am running out of space.
> I have scrounged up an 4gb IDE drive.
> When I add the IDE drive, grub views the new drive as HD0 and my SCSI
> drive as HD1.  No real surprise there.
>
> When I would boot I would get the grub prompt, and when I would type
> root (hd1,0)
> kernel /vmlinuz-2.4.18-19.7.x ro root=/dev/sda5
> initrd /initrd-2.4.18-19.7.x.img
> boot
>
> The system would fire up correctly.
>
> Now, thinking I was smart (I'm a newbie at mucking around with grub at
> this level by the way) I changed my grub.conf file to point to (hd1,0)
> instead of (hd0,0).  Well that didn't work.
>
> So I tried:
> install (hd1,0)/grub/stage1 (hd0,0) (hd1,0)/grub/stage2 p
> (hd1,0)/grub/grub.conf
> And I got a partition doesnt exist.  (now I know, I don't need the
> partition number on the install parameter, but whoops)
> So I checked the drive info with geometry and made a partion of type
> 0x83 for the whole size of the drive, and then ran the install above 
> again.
>
> Now when I boot, it goes through some of the boot process, but now it
> hangs with GRUB at the bottom of the screen.  I'm  guessing I've futzed
> up the MBR on my IDE drive.
> I was able to get everything back by changing my grub.conf to point to
> (hd0,0) and doing an install to (hd0,0) and (hd0) for everything.
>
> So now 2 questions:
> 1) what's the easiest way to get the MBR on the IDE drive un-messed up?  

Unless it is hardware failure, I doubt it is "messed up" in any way that 
a new write of the MBR won't totally fix it. Most likely when the system 
goes to boot to the scsi drive, you left out support for the 
scsi...either it is a module and you failed to add it to the initial 
ramdisk, or else it isn't there at all. The BIOS can access it, but the 
kernel must know how to access scsi once it gets control during the 
initial grub loading. Double check your mkinitrd and the produced 
initial ramdisk, telling it to force addition of scsi modules even if it 
doesn't think you need them.

D. Stimits, stimits AT attbi DOT com

>
> I suppose I could pop it into another machine as a slave and fix it there.
> 2) what are the steps I should take to install an IDE drive, thus making
> my current SCSI drive (hd1) without having to move my installation over
> to the IDE from the SCSI?
>
> Thanks
> Andy
> majolley at earthlink.net
>
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