Hey,

I'm trying to install Ubuntu 9.04 and Scientific Linux 5.3 on my Toshiba Satellite laptop. But no matter the order of installation, or change the settings, I cannot get them to work together.

I am aware that Scientific Linux doesn't like having another distro with / as root, so I worked under the assumption that I should install SL first, then Ubuntu. But I come up with GRUB problems. I get:

GRUB Loading stage1.5.
GRUB loading, please wait...
Error 15

and the system freezes.

Should I install the SL distro, with the SL GRUB then the Ubuntu distro and it's GRUB, or variations?

I don't care which order I install the distros, as long as I get them both working where I can boot either at start up.

Please help! It's been driving me mad.

You should have one install its GRUB to the MBR and make the other one install its own GRUB to its own boot partition and then add a chainload entry to the GRUB in the MBR, like this:

title distro_name
root (hdx,x)
chainloader +1

Right, just so I get this right (I have a 100GB hard drive):

I should install SL, with the SL GRUB boot loader, with (for instance):

/dev/sda1 /boot ext3 100MB (create the partition but not use it)
/dev/sda2 swap 1024 (my RAM is 512MB)
/dev/sda3 / ext3 10000
/dev/sda4 /home ext3 25000 (to create a 25GB SL partition)


Then install Ubuntu9.04, should I select the first option (install side-by-side) or the third option (use up all available space)?

Then choose the GRUB boot loader to be /dev/sda1

Then add the chainload entry to the SL boot loader:

title scientific linux
root (hd0,0)
chainloader +1

Is this the right thing to do?

Yes but make sure to install GRUB to /dev/sda1 (unless you want SL GRUB in the MBR, then you would have Ubuntu install its GRUB to its /boot partition).
By the way, why use a separate boot partition if it uses the same filesystem type as /? Oh yes, and obviously, in your scheme, /home can't be sda4 because that would be the extended partition; /home would be the first logical partition, i.e. sda5.

You choose but I tend to prefer manual partitioning.

No, that doesn't make sense. Why would you add an entry for SL to the SL bootloader - it already has one. It's for the other distro that you need to add a new entry.

Oh I think I get it.

So I first install SL with (say):

/dev/sda1 swap 1024MB
/dev/sda2 / 10000MB
/dev/sda5 /home 25000MB

with the SL GRUB (install to (hd0,0).

Then install Ubuntu

/dev/sda6 / 10000MB
/dev/sda7 /home 50000MB

with the Ubuntu GRUB as well (install to sda6).

Then reboot the whole system, and in SL, go to /boot/grub/menu.lst

and add:

title Ubuntu 9.04
root (hd0,1)
chainloader +1

Will that work? I'm concerned that I have two / (root) partitions becuase SL doesn't like that, or is it ok? Could I install Ubuntu, then SL this way?

No. hd0,0 is the first partition of the first drive. You need to install to the MBR (=sda).

And hd0,1 is the second partition of the first drive - which is your SL / partition. You need to reference the root partition of the ubuntu system. If it is sda6, then it would be hd0,5.

Neither should be a problem. As it uses UUIDs, Ubuntu certainly won't stumble over SL and if SL uses either labels or UUIDS, it won't stumble over Ubuntu either.

I've now installed the two distros, but having GRUB problems.

I installed Ubuntu first, with the GRUB loader on /dev/sda, then installed SL with the GRUB on (hd0,2).

However, when I boot up the computer, it skips the Ubuntu GRUB and goes to the SL one, which only has SL as it's option. I tried to add the Ubuntu OS to the SL GRUB:

title Ubuntu 9.04
root (hd0,0) (I tried various different roots: hd0 or hd0,4 or similar
makeactive
chainloader +1

Then I tried:

title Ubuntu 9.04
uuid c68f201e-e613-4480-8138-dd061f73673e
kernel /boot/vmlinuz-2.6.28-11-generic root=UUID=c68f201e-e613-4480-8138-dd061f73673e ro quiet splash
initrd /boot/initrd.img-2.6.28-11-generic
quiet

Which also didn't work. I either get error 12, 13 or 15.

That doesn't make much sense to me. So you installed SL GRUB to the boot partition of your Ubuntu system?? It should be installed on the SL boot partition.

Well, obviously, no. For the chainloading trick to work, a system needs to have GRUB on its boot partition. But from what I understand, Ubuntu GRUB was installed to sda, i.e. the MBR. Ergo: boot issues.

So let's repeat:
install Ubuntu, let it install its GRUB to the MBR (sda).
then install SL, let it install GRUB to its own boot partition (or / partition if you do not use a separate boot partition).
Then boot into ubuntu and add a chainloading entry for SL to its GRUB configuration file.

I think I've tried that.

I've installed Ubuntu with GRUB going to MBR (/dev/sda).

Then installed SL with GRUB going to /.

Then booted up my computer, but GRUB only thinks SL is there, I cannot boot ubuntu without the live cd. I've gone into ubuntu on the live cd and looked at the boot bit, where only the SL kernels are, so I copied the ubuntu kernels across to it, but still getting error 15: file not found.

I type in:

sudo update-grub

whilst in /boot, but it doesn't recognise the ubuntu kernels.

Ah! I've got it!

I had to not define the uuid, and redefine the path to the kernel and initrd:

title Ubuntu 9.04
kernel /vmlinuz-2.6.28-11-generic root=UUID=c68f201e-e613-4480-8138-dd061f73673e ro quiet splash
initrd /initrd.img-2.6.28-11-generic

I'm so relieved!

Thank you so much for your help! Couldn't have done it without you.