10-18-2008, 12:51 AM
Target Disk Mode and booting from an external drive (USB or FW) aren't the same thing.
It can be very helpful sometimes to be able to treat a sick Mac as a large external hard drive and poke around in it from within another machine. If you try to boot from an external drive you're still depending on the sick Mac's RAM and other hardware to be essentially whole, which it may not be. In such a case you also potentially threaten your external boot disk if bad hardware munges the OS on the external disk.
Target Disk mode has taken on added usefulness in recent years from Migration Assistant's appearance too, because Migration Assistant is all about transferring a huge chunk of data --- there is no better way to do that than to hook both computers up as if treating one of them as an external drive. Again, that's a real strength of FW.
It can be very helpful sometimes to be able to treat a sick Mac as a large external hard drive and poke around in it from within another machine. If you try to boot from an external drive you're still depending on the sick Mac's RAM and other hardware to be essentially whole, which it may not be. In such a case you also potentially threaten your external boot disk if bad hardware munges the OS on the external disk.
Target Disk mode has taken on added usefulness in recent years from Migration Assistant's appearance too, because Migration Assistant is all about transferring a huge chunk of data --- there is no better way to do that than to hook both computers up as if treating one of them as an external drive. Again, that's a real strength of FW.