5 Replies Latest reply: May 7, 2010 3:46 PM by den.thed
Schucon Level 1 (0 points)
I have gotten a lot of conflicting information on what I can and cannot use for external hard drives with my iMac. I was looking at a 2TB Seagate USB 2. But was told that it was not Mac oompatible. Also told that all I have to do is use Disk Utility and reformat it at start. Often drives are compatible just not "Mac Ready". Who is right? Can I buy most if not all USB and Firewire drive on the market and simply reformat?

iMac 21.5, Mac OS X (10.6.3)
  • a brody Level 9 (65,758 points)
    USB 2 in spite of specs is actually slower than Firewire 400.

    USB 2 can't boot PowerPC Macs to Mac OS X, but since you have an Intel Mac, that doesn't matter in your case.

    USB 2 speeds are about 150 Mbps for data transfer, and is slower than Firewire 400 or 800 when it comes to booting.

    To make a drive ready for Intel Macs, use Disk Utility to partition and format it with the option under partitions for GUID formatting.

    A few drives like Maxtor's onetouch have built-in backup software in their boot block. This sometimes has to be removed or disabled before it will work normally with some Mac operating systems, unless you can update the backup software to be compatible with the Mac operating system that is loaded.
  • Eric Cote Level 2 (455 points)
    I use a Seagate FreeAgent 320 with my iMac. It was listed as Mac-compatible.

    When I first started using it with a Powerbook running Tiger, write speed was horrible and I had to go through hoops to get it to stop going to sleep every 2 minutes. I finally found a driver form the seagate support site and everything was good after that.

    Plugged it into the new iMac (10.6.3) and never needed to install anything. works as intended.

    You run into these issues because of the controller and firmware the drive uses, so it's not cut and dry, but yes, most (popular and reputable) gear should be usable.
  • den.thed Level 7 (26,002 points)
    Hi Schucon

    That Seagate USB and about 99% of all other off the shelf MS-DOS FAT-32 formatted External HD's will work just fine, however you may want to use Disk Utility to erase and format it depending on how you plan to use it.

    See >http://www.kenstone.net/fcphomepage/partitioningtiger.html

    If you plan to use the External HD for Bootable Cloning or Time Machine then for an Intel iMac you will want to set the Partition Map Scheme to GUID Partition Table and the Format to Mac OS Extended Journaled.

    However if you want to use the External HD to store for example just music and photos to share cross platform between Mac's and PC's then just erase it and leave the factory Partition Map Scheme set to MS-DOS and the Format FAT-32.

  • Schucon Level 1 (0 points)
    Thanks for your help!
  • den.thed Level 7 (26,002 points)
    Your welcome!