We purchased a new FireWire-connected hard disk drive case yesterday. We now have four external drive cases. We notice that some people are interested in knowing whether it’s possible to install Mac OS on a particular external hard disk drive. If it’s a USB-powered disk drive, the answer is flatly no. So one necessary (but not sufficient) qualification for the drive to be used as Mac OS startup drive is having a FireWire connection port.
 Screenshot 01 – Source: MacHouse |
 Screenshot 02 – Source: MacHouse |
So we’ve tried installing Mac OS X 10.5 on this new hard disk drive case, which has both FireWire and USB ports. It doesn’t take a 15-year Mac veteran to figure out that the first step is to insert an OS startup DVD to the computer. Then I need to use the Startup Disk pane to select the installation disc and click on the restart button. (See Screenshot 01.) The target drive is named ‘160 GB.’ When the iMac starts up on the installation disc, I see the ‘Select a Destination’ screen. We know that Mac OS can only be installed on a volume with a downward-looking, yellow-green arrow. Looking at the computer screen, it doesn’t look like we can install Mac OS X 10.5 on 160 GB. (See Screenshot 02.)
 Screenshot 03 – Source: MacHouse |
 Screenshot 04 – Source: MacHouse |
 Screenshot 05 – Source: MacHouse |
What did I wrong? Is it the matter of how to format the hard disk drive? Or it’s how the hard disk drive is designed that prevents me from installing Mac OS? Okay. Let’s go over partition options. Using Disk Utility, I need to select the drive at first. Then if I click on Options… Hmm… The Options button is grayed out. (See Screenshot 03.) So let’s set the volume scheme to 1 Partition. The same button is now clickable. (See Screenshot 04.) The next screen lists three partition schemes.
GUID Partition Table
Apple Partition Map
Master Boot Record
(See Screenshot 05.) Hmm… GUID? The word doesn’t quite sound familiar to me. Its description says
To use the disk to start up an Intel-based Mac, or to use the disk as a non-startup disk with any Mac with Mac OS X version 10.4 or later.
For this iMac 2.8 GHz Cure 2 Duo, GUID Partition Table may be the one to use. Then I’ll click on Apply and Partition in the next screen. (See Screenshot 06-7.) Finally, let’s boot the computer on the installation disc once again.
 Screenshot 06 – Source: MacHouse |
 Screenshot 07 – Source: MacHouse |
It now looks like Leopard can be installed on the target drive. I see a downward-looking, yellow-green arrow on 160 GB. (See Screenshot 08.) I’m still skeptical, but I’ll move on. After disabling all additional features on the customization screen, the installation disc finally starts copying files to 160 GB. (See Screenshots 09-10.)
 Screenshot 08 – Source: MacHouse |
 Screenshot 09 – Source: MacHouse |
 Screenshot 10 – Source: MacHouse |
After waiting for about 40 minutes, installation is complete. And the computer has been booted on the startup system installed on the external disk drive. (See Screenshots 11-2.)
 Screenshot 11 – Source: MacHouse |
 Screenshot 12 – Source: MacHouse |
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