[Techtalk] grub

[Wim De Smet]

On Fri, Aug 29, 2008 at 3:41 AM, Robyn Willison <robyn at robynspcs.com> wrote:
> On Fri, 2008-08-29 at 03:41 +0530, Mani A wrote:
>> On Thu, Aug 28, 2008 at 8:29 PM, Robyn Willison <robyn at robynspcs.com> wrote:
>> > I have 3 os's on my desktop pc Vista, Ubuntu 8.04 and Debian from
>> > Scratch. How do I stop Ubuntu and Debian from fighting over Grub? If I
>> > update a Debian kernel then it uses it's own menu.lst file instead of
>> > the Ubuntu one which is the main one.
>> >
>> > Does this make sense to anyone?
>> >
>> Install the grub of Debian to its root partition and that of Ubuntu's
>> to the MBR.
>> Adjust the Ubuntu's grub.conf/menu.lst as you want. E.g chainload Debian's Grub
>>
> What is chainload and what do I have to put in menu.lst and where. The
> grub man files don't have anything on menu.lst
>

I googled around for some documentation, here's the manual online:
http://www.gnu.org/software/grub/manual/html_node/Configuration.html

In any case, what you probably want to do is go into Debian or Ubuntu
and "dpkg-reconfigure grub" where you tell it to install into the boot
sector of the current partition instead of the MBR. I'm not entirely
sure if it asks you, if not let us know. After that, boot into the
other one and edit the grub file in a part where automatic updates
won't overwrite it. (Could be that you can put it anywhere you want
I'm not sure).

The actual lines will be almost completely similar to how you boot
windows. From the manual above:
# For booting Windows NT or Windows95
title Windows NT / Windows 95 boot menu
root        (hd0,0)
makeactive
chainloader +1

Just use that but with appropiate title, partition etc. The only
downside is that this will load the other boot loader, and if that has
a menu set up you will have to press enter twice of course.

Other options include:
1) Setting do_bootloader=no in /etc/kernel-img.conf on one of the
installs so it doesn't try to update the bootloader, I think. So
you'll have to manually or otherwise keep the menu.lst of the other
updated.
2) Sharing a menu.lst but that probably works best if the /boot
partition is shared between installs.

greets,
Wim