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I have Windows installed on one SSD. The SATA cable is currently unplugged because I'm about to install two Linux distros on another SSD, those being Linux Mint 14 and BackTrack 5.

Now, I used GParted to create the following partitions on the sda SSD:

  • sda1 with Ext4 file system for Linux Mint
  • sda2 with Swap for Linux Mint
  • sda3 with Ext4 file system for BackTrack 5
  • sda4 with Swap for BackTrack 5
  • sda5 with Ext4 file system for /Home (to share file among distros)

Now, I'm in the process of installing Linux Mint. It's asking me where I want to install GRUB. Ideally, I want to switch my BIOS to boot from the hard drive where my Linux distros are on, because I've read that GRUB will see Windows and add it to its menu. This seems to be the easiest method of triple booting (2 Linux, 1 Windows).

However, do I install GRUB on the sda hard drive? I placed a boot flag on the sda1 partition, so should I install it there instead?

sda hard drive? sda1 partition?

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I have a similar setup, sda for Windows, sdb1 with /boot of first distro and boot flag sdb2 with /boot of 2nd distro sdb6 and sdb6 for the distros.

What I did is install GRUB on the sdb drive and make my bios boot from that drive first. I also had installs with GRUB in the MBR and on both occasions windows was available.

however I am installing 2 distros and I have the problem that GRUB does only see 1 distro and windows, depending on from which install I install GRUB maybe a shared boot partition would solve this problem.

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Boot flag has nothing to do with booting and grub. It is used by Windows to know which partition you boot from with Windows. A few BIOS need a boot flag on a primary partition, so we still suggest one, but which partition does not matter.

Do not share /home. You likely will get configuration conflicts. But you can share all your data in a shared data partition.

Keep grub from the install you use the most in the MBR to boot. You will have to update each grub when you get updates with sudo update-grub so the boot version of grub has the latest info. os-prober usually looks at the other grub.cfg file to find its entries.

More advanced but better when you get multiple installs is to use 40_custom and manually create your own boot stanza to boot a partition not the specific kernel.

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