Formatting 2TB Internal Data Drive for both Mac & Windows?

Discussion in 'Windows, Linux & Others on the Mac' started by sng08, Sep 15, 2010.

  1. sng08 macrumors member

    Aug 30, 2010
    Hi All,

    Well... I went for it... and just received my brand new iMac 27" i7 today (2.93Ghz /2TB HDD + 256GB SSD/12GB RAM (4GB stock, although I upgraded 8GB more)) and I couldn't be happier. It's absolutely wonderful although it really burnt my wallet!!

    I have managed to successfully install Windows XP via Boot Camp and have both Mac OSX & Windows running natively. I am very suprised that XP can see all the hard drives available within the mac itself even though they are HFS although I assume I cannot write onto them.

    I believe I am at the stage where I would like to partition the 2TB HDD as discussed previously in my previous questions on this board. I would like 1TB for mac data storage (Mac OS extended) but I would like the other 1TB for Windows data storage (NTFS), however, this does not seem possible in the disk utility There is, however, an option for 'free space' or ExFat (FAT 32). Would I be right in saying I could format the hard drive as 2 partitions, partition 1 being Mac OS Extended and the 2nd Partition as free space or ExFat via Disk Utility. Once that is complete, I boot up XP and right click on the 2nd Parition which is ExFAT or Free Space and reformat the partition as NTFS? Does that work and make sense or is that stupidity?

    I hope someone can help! Man thanks in advance.

    (also on a side note, completely off topic, does anyone know how to get the magic mouse working in XP? I've got the keyboard (wired) working fine, however, the mouse doesn't seem to commicate. I've followed the tutorial/guides of adding the bluetooth mouse but when I tick the box "keyboard, mouse and misc functions (HID)" it states "access denied". I've tried several times and the device that i've just added disappears?
  2. Tomple macrumors 6502a


    Dec 12, 2008
    New York, New York
    posted by sevendusted a while ago (different forum)

    saved this as a doc file...not sure where i got it from, butg it DID work. I was able to install osx on the mac partition and it was bootable on a mac. The mac side is able to see both the mac partition and the win partition. The windows partition was ONLY able to see the windows side. good luck:

    1) Determine the device (e.g. /dev/disk1) associated with your disk. I will be using disk1 and rdisk1 in my examples. You can use steps 2 through 4 in the original hint to find the correct number for your disk. Unmount any partitions that are already on the disk (ejecting from Finder is sufficient). These partitions will be deleted.
    2) I made two new partitions, one 18GB Mac (HFS+) called "Mac" and one 10G FAT32 (MS-DOS) called "PC":
    diskutil partitionDisk disk1 2 HFS+ Mac 18G MS-DOS PC 10G
    3) Unmount the newly created partitions (eject from Finder).
    4) Get the partition information. You can use the command pdisk in Terminal. Enter l (lower case L) to list a device's partition map and then /dev/disk1. Then q to quit pdisk. Here's what mine looked like:
    /dev/disk3 map block size=512
    #: type name length base ( size )
    1: Apple_partition_map Apple 63 @ 1
    2: Apple_Free 0+@ 64
    3: Apple_HFS Apple_HFS_Untitled_2 37486592 @ 262208 ( 17.9G)
    4: DOS_FAT_32 DOS_FAT_32_Untitled_3 20856304 @ 37748800 ( 9.9G)
    5: Apple_Free 0+@ 58605104
    5) Now use fdisk to create the master boot record (MBR) so Windows will recognize the FAT32 partition:
    fdisk -e /dev/rdisk1
    When prompted to initialize the partition table, enter y.
    fdisk doesn't actually create any partitions. It just edits the MBR partition table. That's what the information from pdisk is for. The MBR created by fdisk can only contain information about four partitions. The important ones to enter are the Apple partition map and the HFS+ and FAT32 partitions. This means that in step 2, you can create a total of three partitions. The commands for the two partitions I created are:
    edit 1
    partition id: af (I wasn't sure what partition id to use for the Apple partition map so I just used HFS+)
    edit in CHS mode? n
    partition offset: 1 (This is the value in the base column for the Apple partition map in the output from pdisk.)
    partition size: 63 (from the length column for the partition map)
    edit 2
    partition id: af (for HFS+)
    edit in CHS mode? n
    partition offset: 262208 (from the base column for the HFS partition in the output from pdisk)
    partition size: 37486592 (from the length column for the HFS partition)
    edit 3
    partition id: c (for Win95 FAT32L)
    edit in CHS mode? n
    partition offset: 37748800 (from the base column for the FAT32 partition)
    partition size: 20856304 (from the length column for the FAT32 partition)
    You can verify what you've entered using the print command:
    Starting Ending
    #: id cyl hd sec - cyl hd sec [ start - size]
    1: AF 0 0 2 - 0 1 1 [ 1 - 63] HFS+
    2: AF 16 82 3 - 1023 192 19 [ 262208 - 37486592] HFS+
    3: 0C 1023 192 20 - 1023 254 47 [ 37748800 - 20856304] Win95 FAT32L
    4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
    Nothing is written to the partition table yet so use the write command to do that. Then quit to exit fdisk.
    You're done. If you compare this process to the one described by simoncha, you'll see that it's basically the same except that I left out steps 5 and 7 through 10. This is because I was getting "invalid argument" at step 10 and nothing was being written back to the partition table. Since step 10 wasn't really doing anything, the other steps aren't needed.
  3. balamw Moderator


    Staff Member

    Aug 16, 2005
    New England
    You should not have to do anything as complicated as the previous post!

    Do you want to be able to boot from the HFS+ partition?

    Intel Macs will only boot from GPT disks and XP really prefers MBR.

    If you don't need to boot from it I would remove all partitions, and create two new MBR partitions. Make the first one HFS+ and the second one FAT32 (MS-DOS).

    Then reboot to XP and convert the FAT32 partition to NTFS.

  4. sng08 thread starter macrumors member

    Aug 30, 2010
    Tomple: Thanks for your comment but that sounds awfully complicated for what I need?!

    Balamw: Sorry I forgot to mention that I am booting both Operating Systems + Applications on the 256GB SSD Drive (I partitioned the 256 equally). So I will only use the 2TB as storage for data files. So therefore, I believe your last comment about remove the existing partition created by apple, and re-partition the HDD with 2 new ones, one being HFS+ and the other MS-DOS, and reformat MS-DOS in Windows as NTFS.

    So what exactly is the difference between 'Free Space' and ExFat and even MS-DOS??

  5. Grannyville7989 macrumors 6502a


    Aug 2, 2010
    I think Free Space means storage space that hasn't been allocated to a particular partition. I may be wrong on this, because I haven't got immediate access to my MacBook Pro but balamw should correct me on this.

    MS-DOS is FAT32. It's a file system that both Windows and Mac OS X can read and write to. Also, Windows XP is able to boot from a FAT32 drive whereas Windows Vista and 7 requite NTFS to be installed on.

    I think Apple should not name FAT32 as MS-DOS because MS-DOS technically requires FAT16 but is incompatible with FAT32. I think the term ExFAT is the same as what Apple calls the MS-DOS file system.. However, there is a bit of confusion because Microsoft have a file system in Windows Vista SP1 and Windows 7 called 'exFAT' that is designed to be more efficient with USB flash drives compared to FAT32 and NTFS.
  6. balamw Moderator


    Staff Member

    Aug 16, 2005
    New England
    My understanding was that MS-DOS in Mac OS Disk Utility referred to all three FATs FAT12/FAT16 and FAT32 (since the latter was introduced in Windows 98 which was MS-DOS based it seems "correct"). It just picks the least inefficient one based on the size of the drive selected.

    As Granny says exFAT is the next major revision to the time honored FAT file system. It's proprietary and patent encumbered and as far as we know no Mac support has been released or announced.

    EDIT: I take it back. Apparently only the 27" iMacs have exFAT support in OS X Maybe 10.6.5 will bring this to the rest of us.

    XPSP3 is supposed to support exFAT so you could just try it. Worst case scenario is that you have to delete it again in XP and replace with FAT32. For maximal compatibility with XP remember to use MBR partitions, not GPT or Apple Partition Map.

  7. sng08 thread starter macrumors member

    Aug 30, 2010
    Hmm... Since my post, I partitioned the Hard Drive as follows:

    2TB > 1TB = Mac OS Extended (HFS+) / 1TB = MS-DOS (FAT)

    I then went into XP and reformatted the FAT Drive as NTFS. However, I set the partition in Mac as GPT (GUID Partition Table) not as MBR, which I believe means Master Boot Record??

    Should I have any problems with the with I have done it? Thanks!
  8. balamw Moderator


    Staff Member

    Aug 16, 2005
    New England
    I suggested MBR for maximum compatibility with XP.

    OS X actually uses a hybrid GPT/MBR scheme to enable Boot Camp XP, but there is a (small) risk of XP deciding to modify the partition table and the GPT and MBR image of it thus getting out of sync. (The "MBR" partition table is really only a translation of the real GPT partition table).

    You should be fine. If you ever upgrade, go to W764 and it'll be able to handle GPT natively.

  9. sng08 thread starter macrumors member

    Aug 30, 2010
    Thanks for the clarification! I think I'll upgrade to W7 sometime next year. Thanks again.

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