GUID vs. APM on Intel Macs?

S

sp_clark

Registered
Apple recommends GUID partition mapping for drives to boot Intel Macs.

I've had a Mac Pro for over a year now; Apple Partition Map works for boot drives on it just fine.

Why is GUID superior for Intel Macs over the PowerPC-recommended APM mapping format?
 
Well, I found out that you cannot install Leopard on the drive if it is not GUID. So, that part of the family pack is still unused--I plan on copying everything off later this weekend and repartition.

I can't speak to superior but it looks like it is becoming required.
 
Something being required at some point does not make something superior.
Just as they started to use USB2.0 on iPods instead of Firewire does not make USB2.0 superior to Firewire...
 
APM formatted drives will boot both PPC and Intel Macs.
The newer GUID Partition Table (GPT) is part of the EFI standard, which on Windows systems is replacing the older BIOS. So, GPT is part of what you get with the association with Intel.
Anyway, a GPT formatted drive won't boot a PPC Mac, which requires APM.

You can't install OS X on an APT formatted drive attached to an Intel Mac, but it will boot that Intel Mac if it is already installed.... so, install OS X on an external drive from a PPC Mac, and you get a drive that can boot most any system (assuming an OS X version that's new enough to support that system)

Is GPT better than APT? Depends on how you define 'better', I suppose....
I would use the label "New! and Improved!"
You decide!
 
Gia, I was only saying that it is "better" in the enforced obsolescence sort of way DeltaMac hit on. It is not better but it is "New! and Improved! with Flavor Crystals!"
 
DeltaMac said:
APM formatted drives will boot both PPC and Intel Macs. (snip) Anyway, a GPT formatted drive won't boot a PPC Mac, which requires APM.
Click to expand...

This morning I tried to boot my Mac Pro off an APM-formatted drive with a Carbon Copy clone of 10.4.8 from this very same machine.

Didn't work. It started from my default drive (GUID) instead, now running Leopard.

Yesterday I tried booting a new Mac Pro off a clone of it's Leopard OS on a GUID drive & that didn't work either.

I'm confused....

I'm going to clone a Leopard OS drive over to an APM disk & see if that'll boot a Mac Pro next.
 
1. OS X won't install on an APM drive if you try the install from an Intel Mac.
2. OS X won't install on a GUID drive if you try to install from a PPC Mac.
3. OS X won't boot on an PPC Mac from a GUID drive.
4. You can boot either a PPC or an Intel Mac from an APM drive (keeping in mind 1 and 2), so you have to install from a PPC Mac to get an APM volume that could boot both.
And, you need to have an OS X version on that partition that would be acceptable on both PPC and Intel, of course.
I don't know if this can work with Tiger (I never attempted), but I know it will work with Leopard.
 
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