[Wylug-help] Grub, dual boot query

[Don Magee]

Mike wrote:
> Hi, Don,
> 
> I'm using v3.7 but /lib/grub/i386-pc/stage1 is there. It's written in
> gobbledegook but I could discern the words "GRUB Geom Hard Disk Read
> Error >>". Does that tell us why the command grub-floppy with-or-without
> /dev/fd0 doesn't work? And does it have a bearing on the whole problem,
> e.g. some fault on hda (IDE0), like its jumpers set for stand-alone
> rather than master now whilst I'm assuming master is master whether one
> or two HDDs present - is that a realistic possibility?
> 
> One other potential fly in my ointment is that the HDDs available both
> had FC2 loaded earlier, so I'm wondering if that is what Knoppix is
> showing, i.e. no viable FC4 installation anyway. The device map
> (read-only) in the grub directory on hdb1 shows fd0 and hd0, which is
> worrying because that would be a true picture of when FC2 was on one of
> the HDDs, jump connectors positioned for master. Knoppix is telling me I
> don't have permission to read grub.conf.
> 
> When I get time, I'll finish off burning the iso images downloaded onto
> this machine and try them. In the meanwhile, if you wouldn't mind
> emailing me a grub image, I may at least be able to find what is on that
> HDD. If it is FC4, the chances are that reconfiguring grub will be the
> answer however many times I download the iso images!
> 
> One query still in my mind is whether there is any way of finding out if
> anything at all was written to MBR on hda on the three or four attempts
> I have made to load FC4? Is all of this, therefore, down to an unclean
> dowload or burn of just one of the four iso images? Each one shows
> pretty much what I would expect when I examine them with GNOME.
> 
> Regards,
> 
> Mike
> 
> 
> 
> 

Mike

You've found the grub files so you can make the grub boot disk with dd.

Put a blank formatted floppy in the drive, su to root, cd to 
/lib/grub/i386-pc, then type

dd if=stage1 of=/dev/fd0 bs=512 count=1
dd if=stage2 of=/dev/fd0 bs=512 seek=1

That should make a grub boot disk. grub-floppy just automates the process.

Then boot from the floppy. That should give you the grub> prompt.

To boot type

root (hd1,0)
kernel (hd1,0)/vmlinuz
boot

That should boot up if you have a credible system on /dev/hdb1. If the 
kernel line fails to find the kernel you may need to look around to find 
out where it is and what it's called. It may work with

kernel (hd1,0)/boot/vmlinuz

Or try

find /vmlinuz



You can look at the boot sector of hda with

hexedit /dev/hda      (as root)

I suspect that you'll find a windows boot loader.

It might be better to put the boot loader onto hdb and then swap the 
master and slave settings round. Then you can boot windows (now on the 
slave drive) by suitable entries in grub.conf. There's a good 
explanation of how to do that in one of the earlier mails in this thread 
from Dave Roberts.


Regards


Don Magee