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I have two linux distros that I want to dual-boot off a single 140GB serial ATA drive what I want to do is set up both distros so that I can boot either of them whenever I start up, I've done this with windows which was fairly simple since all I needed was to install the distro on a seperate partition and it pretty much did this all automagically

but at this time I have a Linux OS and I want to boot Ubuntu as a secondary OS, how would I go about doing this, how would I have to partition my drive and what set up would I need to get them to dual boot, I have no problem re-installing my current Linux Distro since I back up all my files on an external, and my set up is rather basic plus with this I'm hoping to also create a shared folder between the 2 OS systems

the Distros I'm using are BackTrack 5 R2 Ubuntu 12.04 LTS

I really need help with this since my first attempt broke BackTrack and wouldn't let it boot up anymore

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What I'm trying to do is something like this, but I don't understand how it was set up shared /home (accessable by both Linux Distros) having basically 4 partitions (reality 2 x primary, 1 x extended, 2 x logical located in the extended) 2 primary holding os's 1 extended holding /swap and /home – Fate Jul 22 '12 at 22:36
up vote 0 down vote accepted

Normally, this is the default behavior when you install most Linux distros and it finds another OS available, whether Windows or Linux. The methods should be the same, except that for windows, you need to make sure you install windows first.

The second Linux distro to be installed will usually detect the existing one, and create a Grub menu for both.

However, the second one will assume it is the main OS, and will setup Grub to look for the configuration file in its own partition, in /boot/grub.

One problem here may be that BackTrack appears to be based on Ubuntu, and perhaps you accidentally performed an upgrade rather than a new install. You should create a new partition, and make sure you install it alongside the existing OS. I usually create the partition first in gparted (actually, I already have some spare partitions for experimenting), then choose "Something Else" from the install menu.

My Setup

I have a 1 TB drive, plus a second 500 GB drive, so disk space is not at a premium for me. I back up to the alternate drive, and also have an old Windows XP on it.

My main drive is partitioned as a single extended partition, no primary partitions at all. I created 3 or 4 20 GB partitions for my main and alternate Linux installs, some swap space, a bit of unused space for various things I've tried (such as /boot partition, /var, etc), and the rest - at the end of the partition - is a "shared" partition with audio, video, photos, documents, etc. I create symbolic links to this in various distros I use so I always have access to my personal stuff. I keep the home directory with the distro, and it has a lot of distro-dependent settings.

I mount the "shared" partition in any installation that needs it, using /etc/fstab to mount the partition into /mnt/shared. The shared partition contains directories such as "Documents", "Music", "Pictures", etc, and I create links to these directories in my home directory. The easy way to do this is to use Nautilus, highlight a directory, right-click and choose "Make a Link". For example, I do this for /mnt/shared/documents, and Nautilus creates a link named "Link to documents". I cut and paste this link into my home directory, and if there are any files int ~/Documents, I move them to /mnt/shared/documents. I then delete Documents in my home directory, and rename "Link to documents" to "Documents". If this is done without logging out, the link will inherit the special icon and will act just like the original.

Repeat this procedure for any other directories, like music, pictures, etc.

When I want to try out a version upgrade, I can copy my current version to a partition so I can go back to it, then I can upgrade without worry, and I always have my data available. It's very easy to copy anything I need from my home directory on a different distro, such as .bashrc, etc.

The only thing to be aware of is the grub configuration. I've accidentally deleted a partition that has the grub files, and this makes the system temporarily unbootable unless you know the drill to boot from the grub prompt - not really hard, but I usually need a guide to remember. But the best thing is to have a bootable rescue CD, such as the Super Grub Disk, which can fix these problems easily.

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how about giving me a run down of the partitions and what you set them up as? – Fate Jul 22 '12 at 21:06
OK, I added "My Setup" to my answer; let me know if you need more info. I've been doing this for a pretty long time now, and I've tried just about every variation of Ubuntu, plus most other distros. – Marty Fried Jul 23 '12 at 0:21
how do you set up the /boot partition shared /home and swap on the installation so when I install the second OS I don't overwrite what was already done by the first – Fate Jul 23 '12 at 0:54
I added instructions for the data directories such as documents. I actually quit using a separate boot partition, as it got confusing. But the way to do it is you mount the partition in /etc/fstab, just like other partitions. But if you don't want it to be overwritten, you would need to unmount it; otherwise, it acts just like the original one, which is the whole idea of mounting it. But I don't mount the data directories, I create links, so it doesn't get overwritten. – Marty Fried Jul 23 '12 at 1:09
so then my harddrive partititons should be 2x 30GB / for the OS and 1x 4gb Swap [minimalist] for a basic dual linux setup? but if I run the simple installers won't they overwrite the MBR? – Fate Jul 23 '12 at 1:16

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