APM on Intel?
 

So...I have a Macbook (intel-based) and made a full backup to a USB drive. Tested it, and booted from it...everything worked fine...

Then started thinking, and realized...I wonder if I had the external formatted correctly. I opened up disk utility and realized it was set on Apple Partition Map. Reading the SD! user manual, it says to use APM for PowerPC computers and to use GUID for intel-based. So...why is this bootable and appear to work fine? Do I need to reformat this as GUID and redo the backup?

Thanks

APM works for Intel. But it's discouraged (and you can't choose it as the startup drive under Leopard, even though it works with Option+boot).

I'd generally suggest repartitioning as "GUID".