problem with GRUB

[Derek Broughton]

Naja Melan wrote:

> hi,
> 
> by now i managed to solve the problem. It turned out that the person at
>
http://www.linuxforums.org/forum/debian-linux-help/54820-cant-boot-kubuntu-after-installation.html
> was exactly right. There is a bug either in grub or the installer from
> kubuntu, however generates the menu.lst file. If you boot from a disk, it
> seems that grub requires this disk to be called hd0.
> 
> menu.lst also has a section like this:
> 
> ## default grub root device
> ## e.g. groot=(hd0,0)
> # groot=(hd2,0)
> 
> maybe after this line hd2 had to be called hd0? It is not entirely clear
> to me, but anyhow, since it is perfectly possible to make a working
> menu.lst, and the installer fails to do that i would call it a bug.

Er, yes...  I misled you there :-(

> Does anyone know who is responsible for this bug, then I would file a bug
> report in the right place. It doesn't seem something you want to leave
> unfixed in a release version of an operating system seems me... (well at
> least being able to boot is kind a basics if you ask me...)

It's not a bug (in grub).  It's simply a matter of grub treating whatever
device it's booted from as (hd0).  I'm not quite sure yet whether there's a
bug in the installer, or just a hole.  I don't think the installer
understands the concept of multiple boot disks - but it could with a little
work.

> Derek, i would like to react to this what you wrote:
> 
> Grub uses its own naming scheme, so even though the hard drive would
> likely
>> be named sdb to linux, grub would probably call it (hd1).  Your internal
>> drive is going to be /dev/sda or /dev/hda to Linux and (hd0) to grub.
>> Specifying (hd0) for grub says to install the boot loader on the master
>> boot record of the internal drive.  (hd1) would be the MBR of the
>> external drive.
>>
> 
> I figured that, but that doesn't mean it is desirable. In fact this should
> not concern the end user. 

It _doesn't_ generally concern the end-user.  You're trying to do something
that wasn't possible at all a few years ago, and still can't be done with
Windows afaik, so it's not been well used and tested.

There were two ways to resolve your problem - take the USB drive out of the
boot sequence, install grub to the internal drive, and tell grub to boot
off (hd2) [which I'm not even sure is possible, as grub may not be able to
find the USB drive] or make the USB drive the first bootable drive, install
grub there, and boot off (hd0).  For the installer to be able to do this,
it needs to ask which of these options you're going to use before it
constructs the menu.lst file, but I agree it's feasible.
-- 
derek