1991 Views 9 Replies Latest reply: May 12, 2007 10:13 AM by Matt Sampson
An Intel Mac can boot from either a firewire or usb drive; a PPC Mac can only boot from firewire.
The external boot drive of an Intel Mac must be partitioned with the GUID partition scheme to be bootable. You can do this via DiskUtility, which comes with the Mac.
I would urge you to choose a Firewire external for your task, because the performance will be much better. This is because Firewire has a dedicated controller for the bus, whereas USB uses the CPU.
To give you an example, I recently cloned my hard drive using a Maxtor Onetouch III external, which has both firewire and usb. I started to do it with the USB interface but then started over with the firewire interface. The throughput on the firewire was 3 times greater, even though both specs are nominally about the same speed. Get firewire; it makes a difference.
GUID is easy to set up. Once the drive is connected, open Disk Utility (Applications>Utilities) and click the first entry for the drive itself (not the volume name if a second entry appears). Then click the 'Partition' tab, then the 'Options' button. Click 'GUID Partition Table' then OK. Set the partition size, then click the 'Partition' button. That creates a GUID partitioned drive from which an Intel Mac can then be booted.
Thank you Andy that's very helpful... it will save me alot of nervous clicking around trying to work out what to do.
Presumably this GUID thing also explains why my current Lacie 500Gb mini hub won't let me load OSX onto it as it isn't GUID partitioned just HFS+ formatted straight out of the box?
Slowly...very slowly the mist is beginning to clear..... I think.
Presumably this GUID thing also explains why my
current Lacie 500Gb mini hub won't let me load OSX
onto it as it isn't GUID partitioned just HFS+
formatted straight out of the box?
That's exactly right, yes. Since it's not a bootable volume as far as your mini is concerned, it won't give it as an option to install MacOS on it.
Incidentally, once GUID partitioned, you don't have to actually INSTALL MacOS if you want to use it in place of your internal drive. You can use CarbonCopyCloner or SuperDuper! to clone the internal to the external as a complete single operation, which will leave you with a bootable external that is an exact duplicate of the internal drive. After that, once the external has been tested out, you can then remove whatever you wish from the internal drive, or use it as a backup for the external.
Either/both CCC and SuperDuper! can be downloaded from www.versiontracker.com.
Thanks for the info on making a USB drive bootable on my Intel Mini. I know had to able to boot from a USB drive. The machine I had before I got the Mini was a Quicksilver (giganet) with a USB 2.0 PCI card. I was able to boot from the USB drive all the time. It didn't matter if it was Mac OS 9 or Mac OS X.
So I am glad that I can still do that. I understand about USB being slower then Firewire. But I can't afford to buy a case that has Firewire on it. (Yes I know youj can get Firewire drive cases for $35 (US). I just don't have the cash at the moment.)
This will alow me to make a bigger bootcamp partion on the interal drive now.
As you rightly indicate, PPC Macs may actually be
able to boot from USB drives - it's not supported by
Apple and not consistent, but many have had success
in doing it. However, while it's rather hit and miss
for PPC systems, USB is a supported boot medium for
Actually Apple does support booting some PPC machines from USB drives
Beginning with the Power Mac G4 (AGP Graphics) and the iMac (Slot-Loading), two new features to USB are most apparent: support for USB audio devices and booting from USB drives.
Thanks again for the advice everyone. Just by way of an update, I bought myself a Lacie 120Gb all Terrain FW/USB HD, managed to partition and reformat it to GUID, cloned my inetrnal drive over using Superduper, tested it successfully and booted from it all without a problem. Now I have piece of mind and 40Gb of portable storage. So if anyone else is wondering about the mechanics/difficulty of doing this don't be, it's actually quite straightforward... just like every one says.