[Techtalk] two ubuntu distros on one computer

[Akkana Peck]

Roberta Gallini writes:
> Hi everybody,
> I have a Linux box working happily with Ubuntu 6.10.
> The machine has two hard disks, one containing the OS, the other my
> home partition.
> I would like to try and use Ubuntu 6.04 64bit without erasing my
> functioning partition and I need some explanation.
> I would like to resize the Ubuntu partition and use a part of the disk
> for the new one.
> What do I need to do, to have grub functioning for both distros?

The easiest way is to have a separate partition for /boot. Then
all of your installed distros can share the same /boot, and your
/boot/grub/menu.lst will have pointers to every combination you
might want to boot.

If /boot is already a separate partition, and you install a new
ubuntu and tell it about /boot when you go through the partitioner,
it will overwrite /boot/grub/menu.lst but will probably give you an
entry for the old installation as well as the new one. Alternately,
if you're mistrustful like I am, you can persuade Ubuntu's installer
not to update grub, then boot into the old distro and edit menu.lst
by hand. But that's more work. Either way, you'll eventually want
to edit menu.lst by hand to give the various boot options clear
names ("dapper", "edgy", etc.) so you can choose them at boot time.

If you want to have separate /boot directories that are part of
each root partition, instead of one shared one, it's a little more
complicated: you have to decide which OS is the master which owns
the "real" /boot and is allowed to update grub. That gets confusing,
especially if you don't change anything for a long time and then
can't remember which one is supposed to be the master. I really
don't recommend it unless you have a good reason for going that way,
since grub works so well with a shared /boot partition.

If you don't have a separate /boot now, you can add one (I think it
has to be a primary partition) when you do the partition resizing.
(In that case, you'll have to copy everything in your current
distro's /boot into the new partition, but don't worry about that
until you have the new install up and running.)

-- 
    ...Akkana
    "Beginning GIMP: From Novice to Professional": http://gimpbook.com