I’d thought that if you wanted to boot Intel Macs you needed to use the recently available GUID partition table, mainly because that’s what it says in Disk Utility when you format the drive. In fact, as it turns out (at least as of Mac OS X 10.5.5), using the Apple Partition Map (APM) boots Intel Macs perfectly well. It’s exceedingly useful to have a partition format that will boot both architectures, particularly at the museum, where Intel and PPC Macs still very much coexist.
Disk Utility Partition Styles: Lies!
In fact, my Mac is a G5, but all the new hardware is, of course, Intel-based. And I’m trying to create a master build image for setting up new machines. Generally the way I do this is by making a test build on a firewire partition. I can boot into this build and tweak it until it’s perfect. And when it is, I image it to an ASR disk image for NetBooting. I was worried that architecture limitations would make this painful — that booting into my test build partition would be impossible on my PPC Mac because of these restrictions. Glad to know I can just use the old reliable APM for everything and it’ll do what I need.
Not sure when or how they worked this out, or why the language in Disk Utility has gone unchanged. That fact does give me pause. But so far booting Intel Macs from APM partitions has worked perfectly for me on multiple machines.
UPDATE:
More info at Apple’s Secrets of the GPT Tech Note, via Jeff in the comments.
8 Comments
That’s funny, I just wrote this morning about booting Intel from APM at http://lapcatsoftware.com/blog/2008/11/02/what-about-sony. Note that http://developer.apple.com/technotes/tn2006/tn2166.html says, “While Intel-based Macintosh computers can boot from GPT and APM, Apple only supports booting Mac OS X on these machines from GPT. Apple’s GUI tools, like the Installer, will prevent you installing Mac OS X for an Intel-based Mac on non-GPT disks.”
Thanks for the info, Jeff.
This sort of posting-about-the-same-thing-someone-else-just-posted-about happens to me all the time. I will try and think of a name for it. Deja-post? No. That’s lame.
Suggestions welcome.
-systemsboy
Versions of OS X prior to 10.5 were either intel or PPC, not Universal….
I believe apple made the APM/GUID requirement as a safeguard from trying
to keep people from booting to an incompatible OS (i.e. booting ppc os x on intel)
10.5 and up are universal binary, so i think that this may have made the APM/GUID issue moot…. So you can probably boot an APM partition, but GUID is preferred/supported.
That’s my theory anyway….
I think, actually, that 10.4.7 and up were Universal Binaries, at least they were for Mac OS X Server. But I have a feeling that the ability to boot Intel on APM probably was disabled in 10.4 for similar reasons.
-systemsboy
I accidentally used SuperDuper to install Tiger on my Macbook Pro on an APM drive, after replacing the hard drive, and had no problems with it until I went to upgrade to Leopard last week… and the installer wouldn’t let me.
I had to back up, re-partition, reinstall, it was a big pain in the tuckus.
Yes, my tuchas is getting sore just thinking about it.
-systemsboy
Sounds like you were able to do what I’d like to do. Just bought a white MacBook dual-Intel with 10.5.2 and want to have a bootable back-up on an external FW 500 GB partitioned into two volumes – where the 2nd volume would be used for a bootable back-up of my old G4 desktop running Panther.
How exactly did you install Leopard onto an APM when everything I’ve read for the past two weeks-close to 24/7-says Leopard installer won’t see APM drive. Would really appreciate a clue.
TIA
An avid Mac-geriatic
I didn’t actually ever install Leopard on an APM partition. I only ever cloned from an existing partition to an APM partition. I’ve also heard that the Leopard installer won’t recognize APM, and it’s probably true. The only workaround I can think of offhand is to install on a GUID partition and then clone that to the APM partition.
-systemsboy