View Full Version : Boot Disk issues

2nd March 2010, 12:18 AM

I have 2 external firewire drives connected to my eMac. The eMac is running 10.5.8, though this issue existed under 10.4.9 too.

Problem is - though the computer recognises one of the drives as a viable startup disk (an "M9" with Oxford 911 chipset), it does not recognise the "MyBook" (Oxford 923?). The odd part is, the MyBook contains 3 partitions - 2 are cloned copies of my eMac's hard drive, and the M9 drive. Thus, I'd have thought, they should be bootable...

The partition map is set as Apple, and they are all set as Mac OS Extended.

Is it simply because the MyBook is a piece of crap? Or can I get it to recognise the other partitions as bootable?



2nd March 2010, 12:41 AM
To make an external disk bootable it has to be formatted with a GUID partition table. You set this up in Disk Utility when you choose the number of partitions. Select the section of the partition map that you want to be bootable and choose Options. GUID is the top one from memory.

2nd March 2010, 06:34 AM
Disk Utility says the GUID is for Intel Macs, or non-startup disks after 10.4.

The middle one - "Apple Partition Map" - is for PowerPC startup disks... which is what it is...

2nd March 2010, 07:20 AM
Ahh, right you are.

2nd March 2010, 07:32 AM

Do you mean when you boot up holding the option key or in system preferences. I know with some of my firewire drives when I boot using the "option key" I have to toggle the power on and off to get them to display.


2nd March 2010, 05:04 PM
Ahuh! Yes, I was referring to the option at startup method.

Under Startup Disk system pref, it does offer all of them. Must be the Oxford 911 chipset at play. (IE 911 is good, others are not as good).

Thanks for that, ajbeardy :)

On another note - is a Time Machine backup (of a bootable disk), bootable?