View Full Version : Boot puzzle . . .

09-25-2006, 01:02 PM
Dear Dave,

It's obvious by scouring these posts you give a rat's behind. Having said that, riddle me this.

I bought a WD Premium 320G and created 3 partitions for two mac backups and one XP. Thought I got Disk Utility to let me have my cake and eat it too. Formatted two to mac osx journaled and one to md-dos. But when I had trouble booting the macs from backup I went back and checked my Partition Scheme. It was MBR. That's your first rule of thumb--check this. But here's the kicker. I could boot with either mac backup to one of the macs, but the other mac wouldn't recognize them! I could see them with Finder and even in Startup Disk on the nonresponsive mac, but they would not show with the Option button or boot by selecting via Startup Disk preference. Again, however, the other mac saw them both and booted just fine with either backup. Go figure.

Anyway, I've decided I need to redo using APM. I'm keeping 3 partitions and making the (hopefully one day) XP partition as FreeSpace. If anyone out there in virtual land knows how to do what I want, I'd be obliged. And no, neither mac is Intel based so I don't believe any of the Boot Camp info is relevant (although I could be mistaken).

Thanks for the look see. Cheers!


09-25-2006, 01:11 PM
I have no idea how to take "you give a rat's behind". Do you mean I don't care?

Neither Mac was Intel, too? You're right: I have no idea how that could work. OpenFirmware definitely wouldn't recognize MBR drives... unless there's been a recent update that I'm unaware of.

What models are the two Macs?

09-25-2006, 01:23 PM
Sorry, no I mean you DO care. I'm very impressed by your quick and thoughtful responses.

Both macs are G4 Powerbooks, although the one that took the boot was the last G4 before the Intels--the one with better screen resolution. The only other difference is harddrive size, 100 vs 80.

The only thing I could think of is that the same computer I partioned the drive with was the same computer that recognized the backups and so maybe that had something to do with it.

Disk Utility is a little funky how it seems to work. I think the bottom line is that you can't partition one part of the drive APM and one part MBR, even though it looks like you can via the settings. Ultimately one takes over the whole drive, and I guess its MBR.

09-25-2006, 01:28 PM
Maybe they updated those last G4s' Open Firmware to boot from MBR. That's not something I've ever seen, though -- I don't think I've managed to get an Intel mac to boot off MBR!

I'll try to find some time to do some additional tests here...

09-28-2006, 09:56 PM

I did a little experiment. Even though I don't have Intel macs, I partitioned my external Firewire as a GUID partition table. This let me format partitions 1 & 2 as osx journaled and partition 3 as ms-dos (FAT32?). I've now backed up all three computers. (By the way, if I can find something as slick as the SD for XP, my life would be much easier.) Anyway, my G4, again, was the last of the PPC breed. It came out about 3 months before the Intel macs (darn it!), but came with the higher resolution screen. I can boot my backup and my wife's backup on that computer. My wife's G4 was the next to last before Intel. Basically same machine (mostly) with the obvious difference of a lower res screen. I cannot boot any backup to her machine.

So I have two choices. Go APM and boot both macs, but no XP backup (unless I find a solution to APM and MBR existing on same drive), or leave GUID and forgo booting on her machine. Her's is about to go in for out-of-warranty repair (again, darn it!), so your SD is very timely. At least she can still use her stuff off of my machine.

Thought I'd just pass this along. However the OpenFirmware works that you mentioned, it sounds like they must have made a change right before the switch-over to Intels. Again, for what it's worth.


09-28-2006, 10:04 PM
Thanks for that information, Turnip -- appreciated!