All hard drives can be made bootable if the following is taken in to consideration.
First, your hard drive has to have a Firewire port. Booting on a Mac using the usb is not supported.
Second, you have to know what kind of computer you have. For example, PowerPC such as a G3,G4,G5 or an Intel based such as a MacPro, MacBookPro, Macbooks, iMac’s or Mac Mini’s with Intel Core Duo processors.
If you have a Power PC then you have to make sure that your hard drive is using the Apple Partition Map. Power PC computers can only boot if the drive connected is formatted as an Apple Partition Map and if it contains an operating system such as Mac OS X (Panther, Tiger, Leopard)
Use the following steps to find out what format your external drive was originally set up as.
1. Using your keyboard press the following three keys:
Shift – Command (Open Apple) and the letter “A” to access your applications folder
2. Scroll down and double click on the folder titled “Utilities”
3. Select the Disk Utility Application and double click to launch it.
4. Select the icon associated to the capacity of your G-Technology Drive
5. Now, to tell if your drive was formatted from Apple Partition Map. If it was, you would see the following…
6. If your drive was formatted as GUID you would see the following.
7. If you need to format your drive as GUID or APM you can do so by accessing the options tab under the Partition section.
8. If you selected the correct option then you should see the following screen.
9. Select the appropriate partition scheme for your system. Click on OK to confirm the selection then click on partition to format your drive. ( Please note: by doing so you will loose all information which may be contained on the drive. So please back up any important information two at least two places.)
10. After your drive is set up correctly then you can use Super Duper to clone your computers drive to the external drive to use it as a boot up drive. Or, you can always install a new operating system on it.