How can I dual boot Ubuntu and Windows 7 if I didn't create logical partitions?

Question

So this problem may sound familiar to a dozen other questions like these but I still haven't found an answer to mine in particular. When I installed Ubuntu I thought that when choosing to install it side by side with Windows it would just add it to the windows booter, but it didn't. And now I've got the problem that I recovered the MBR with my Win 7 disc because I still use that a lot, and I would like to be able to boot Ubuntu from that now.

Here is where the problem comes in. My problem is that since I didn't make a seperate boot partition for GRUB, I didn't think of making logical partitions (I've got 4 primary partitions, with the one with Ubuntu on) and I need to make it extended so that I can free some space up for the boot partition so I can then configure the Win booter to boot it correctly when I choose to.

And why I am just not deleting the whole partition to reinstall it (because I guess you're thinking that since it's such a fresh install why don't I just reinstall?) is because I have spent two days installing software and downloading and the only internet I have is a mobile broadband with limited bandwidth/month.

I'm looking for a way to copy the content which is around 5 gigs to some other drive, or somehow making it an extended drive and shrink it, or erasing the partition, doing this and that, copying it back and then installing GRUB. Would this be possible? Would GRUB be able to pick it up if I were to install it through some other way? Right now I'm on the live CD.

Answer 1

There's no way to convert a partition from primary to logical while keeping the data, as far as I'm aware. So the question boils down to "how do I back up the data from a partition so I can restore it later to another partition and make Ubuntu to boot from that partition".

You'll need an Ubuntu LiveCD/USB and enough space on the Windows partition or somewhere else to store the backup of data. Boot from the LiveCD and mount both the Ubuntu partition and the partition where you're going to store the backup. Then make a backup with something like

sudo tar zcfv /media/my_backup_partition/myubuntu.tar.gz /media/Ubuntu 

(the reason we need to use tar (and sudo) is to preserve permissions. If the backup partition supports Linux permissions you can just copy the files to a directory there)

Then you remove the partition, create an extended partition and logical partitions inside it. Mount the new Ubuntu partition and extract the backup:

sudo tar zxfv /media/my_backup_partition/myubuntu.tar.gz /media/new_ubuntu_partition

Then I think you'll need to edit etc/fstab on the new partition to account for the new filesystem UUID and device name (it'll likely be sda5 instead of sda1..4) or, alternatively, to use tune2fs to change the UUID to match the old one.

Then you'll need to re-install GRUB.

The point is - the whole Ubuntu install is just a bunch of files, you can do with them whatever you can do with files, there's nothing magical about them.