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Thread: Is Triple-booting with Ubuntu in middle possible?

  1. #1
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    Sep 2011
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    Is Triple-booting with Ubuntu in middle possible?

    Hi, I have been using Ubuntu for some time now, but my knowledge seems to fall short when it comes to multibooting.

    My (possibly dumb) question is, is it possible to install Ubuntu to a partition in between an already installed Mac OS X and Windows 7 without messing up the booting of either OS? I have room to make my OS X partition smaller to add a new one after it, but not after Windows 7. I just wanted to make certain before jumping right in and possibly screwing something up. Apologies in advance if this has been asked before/already has been answered.

    It would look something like this when done:

    Mac OS X / Ubuntu / Windows 7
    [==============][==============][===============]
    Last edited by temporalburst; September 7th, 2011 at 10:57 PM.

  2. #2
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    Re: Is Triple-booting with Ubuntu in middle possible?

    If possible it is far better to avoid moving the start point of a partition on disk, and preferable to shrink the first partition and use the free space there to install your ubuntu OS.

    It doesn't really matter where the partitions are on the disk, so is there a particular reason why you want ubuntu between the Mac OS X and Windows 7? Show us a screenshot of your disk from a ubuntu live CD running gparted, if possible. It will give a lot more information than we have at the moment, and show the current number of partitions already on disk.
    DISTRO: Xubuntu 12.04-64bit --- Boot-Repair --- Grub2 wiki & Grub2 Basics --- RootSudo

  3. #3
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    Smile Re: Is Triple-booting with Ubuntu in middle possible?

    It doesn't really matter where the partitions are on the disk, so is there a particular reason why you want ubuntu between the Mac OS X and Windows 7?
    This is mainly what I needed to know, I just didn't know if a partition's location mattered or not. The only real reason for wanting it between OS X and Windows 7 is that I didn't have room to resize Windows 7's partition, but had plenty room to resize OS X's. Thank you!

    Also, I have just two partitions, one for OS X and one for Windows 7 through BootCamp.

  4. #4
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    Re: Is Triple-booting with Ubuntu in middle possible?

    One caveat is that Windows relies on a hybrid MBR to boot on an Intel-based Mac. As described on the page to which I linked, hybrid MBRs are a dangerous hack, and if you do things wrong, you can seriously mess up your computer. Most importantly, you should do your partition resizing from OS X's Disk Utility or some other tool that understands the GUID Partition Table (GPT) partitioning scheme that Intel-based Macs use natively. If you use Windows, it will see the disk as MBR, resize the MBR representations of the partitions, and leave the GPT representations alone, which will create a dangerous inconsistency. I realize you probably wouldn't use a Windows tool to shrink your OS X partition, but I want to point out this danger since I've seen posts and even gotten e-mails from people who've seriously damaged their disks because they used Windows partitioning tools on disks with hybrid MBR configurations.

    A less serious issue, but one that could easily become a stumbling block, is that when you finish installing Ubuntu, you'll probably have a GPT-only disk rather than a hybrid MBR. Various tools will enable you to create a fresh hybrid MBR, but most of these just add the first three partitions (aside from the EFI System Partition, or ESP, which OS X's Disk Utility hides from view) to the MBR side. Depending on how many partitions you use, putting Windows at the end can result in Windows being left out of the MBR, which means that Windows won't work. This problem is easily overcome by a tool that gives you more control over your hybrid MBR creation. I've seen patched versions of gptsync that do this, but these patches don't seem to have caught on. My own GPT fdisk (gdisk) program can do the job, too -- see the earlier hybrid MBR link for details of how to use it to create a hybrid MBR.

    One more point, which is a general multi-booting issue: I strongly recommend creating a separate FAT or NTFS data-exchange partition. It's generally unwise to access any OS's boot partition from another OS, since non-native filesystem support is often imperfect and security features are often useless in other OSes. These limitations make it easy to accidentally trash a boot partition. Using a separate data-exchange partition minimizes these risks and isolates them to a relatively unimportant partition. Such a partition should, of course, be included in the hybrid MBR along with the Windows boot partition.
    If I've suggested a solution to a problem and you're not the original poster, do not try my solution! Problems can seem similar but be different, and a good solution to one problem can make another worse. Post a new thread with your problem details.

  5. #5
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    Ubuntu 12.04 Precise Pangolin

    Re: Is Triple-booting with Ubuntu in middle possible?

    I really do not know Macs.

    But I understand they use the newer gpt partitioning. But Windows will only boot from MBR*, so Apple uses a hybrid to boot Windows in BIOS/MBR mode and Mac in gpt mode. You have to sync teh two versions and the windows then has to be in the first partitions.

    http://www.rodsbooks.com/gdisk/hybrid.html

    *Win7 will boot from UEFI with gpt, but Mac is EFI and Apple does not use the Win7 UEFI mode.
    For info on UEFI boot install & repair:
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to close thread when/if answered completely.







  6. #6
    Join Date
    Sep 2011
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    Re: Is Triple-booting with Ubuntu in middle possible?

    Thanks for all the info. ^_^

    I have Ubuntu installed and running fine now, all three operating systems booting properly as well.

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