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jbarley
Dec 9, 2012, 02:15 PM
The following question was asked on another forum, and the answer has me wondering...

What are your thoughts about this?

Question:
Do you really think an Intel based Mac will boot from a PPC operating system?

Answer:
Yup. I've got a PPC G5 iMac iSight 20" on my wife's desk right next to mine, and it's USB CCC backup drive, both with Leopard 10.5 8 with APM format of course, and they are both bootable with my SL Intel 24" iMac.

So yes, I know it works. But thanks for your concern.

And what's even more interesting to me, is that both have been 'trimmed' of surplus Intel code etc. using Monolingual, so they are both OS X PPC code only. Not too bad Apple.



zackkmac
Dec 9, 2012, 02:19 PM
Well of course the 24" would run it, I believe they came with Leopard when they first released.

Try to run Tiger on a 24" iMac and you'll see it doesn't allow it.

jbarley
Dec 9, 2012, 02:25 PM
Well of course the 24" would run it, I believe they came with Leopard when they first released.

Try to run Tiger on a 24" iMac and you'll see it doesn't allow it.
Did you read the last paragraph?
I find it hard to believe that an OS totally stripped of all intel code and left with only PPC code would boot and run on an intel machine.

I know in my case my G5 CCC backup will not boot on my pre unibody MBP, which originally came with Tiger.

crewkid89
Dec 9, 2012, 02:26 PM
APM is bootable by intel macs. Here is a nifty article explaining how to create a recovery drive with both intel and ppc versions of tiger on the same drive:

http://eshop.macsales.com/articles/booting-your-intel-mac-to-an-apm-formatted-drive

You just can't install it directly to an APM drive.

Booting from an xslimmed or monolinugual-ed drive may be possible but probably not problem free. Those applications blacklist anything of vital importance to the system. Once you started using it, I am sure you would run into issues unless you somehow had rosetta installed on your PowerPC drive.

jbarley
Dec 9, 2012, 02:35 PM
Ah yes, the blacklisting of system files, hadn't thought of that, now maybe there is a slim possibility.

Jethryn Freyman
Dec 10, 2012, 04:20 AM
Yes from what I understand, some Intel Macs [mostly the earlier ones] will boot fine from an APM partition. As far as upgrading the OS goes, though... be ware...

stroked
Dec 10, 2012, 05:55 AM
I think it is the early Intel Macs with the 32 bit EFI, that can boot to a APM drive. My late 2006 C2D iMac will boot to a APM formatted drive.

SuperCyborg
Dec 10, 2012, 06:21 AM
And what's even more interesting to me, is that both have been 'trimmed' of surplus Intel code etc. using Monolingual, so they are both OS X PPC code only. Not too bad Apple.

Monolingual does not trim OS code. Its blacklisted in the program settings.

Also, to trim the kernal would require that you decompile and recompile it.

rabidz7
Dec 10, 2012, 06:24 AM
Of course leopard will boot it is a universal binary just like tiger. Try to boot 10.3, panther.

Zotaccian
Dec 10, 2012, 06:41 AM
Yes it is absolutely impossible for a system to boot if the CPU and OS are in different "language", Intel is x86 and PPC is.... PPC. Emulators do run on operating systems which are made for the CPU so even then, some code which the CPU can directly understand is needed first.

If I remember correctly, IBM had a project where its CPU would either contain both PPC and X86 units or built-in emulator in CPU (can't remember) so it could execute both types. Another option is of course to compile the OS for both languages like Apple and many software makers did for some time.

Jessica Lares
Dec 10, 2012, 06:46 AM
Tiger is NOT universal binary.

Tiger will not boot because the version that was sold/pre-installed for PowerPCs was before the Intel transition. Intel machines came with a special version of OS X Tiger made specifically for the architecture, and you were stuck with grey disks that came with the machine until Leopard came out.

OS X Leopard had both PPC/Intel code, which is why you can boot a PPC disk running it on a Tiger/Leopard/Early SL-era Mac.

And yeah, it would mainly work with just the PowerPC code because of the kernel still being there and Rosetta.

crewkid89
Dec 10, 2012, 09:27 AM
Tiger is NOT universal binary.

Tiger will not boot because the version that was sold/pre-installed for PowerPCs was before the Intel transition. Intel machines came with a special version of OS X Tiger made specifically for the architecture, and you were stuck with grey disks that came with the machine until Leopard came out.

OS X Leopard had both PPC/Intel code, which is why you can boot a PPC disk running it on a Tiger/Leopard/Early SL-era Mac.

And yeah, it would mainly work with just the PowerPC code because of the kernel still being there and Rosetta.

This is what made hackintoshing so damn difficult when it first came around. Only people like my brother who had the full stock of CompUSA sitting in his garage had the right hardware combo to swing it. The distros were really picky.

SuperCyborg
Dec 11, 2012, 06:02 PM
Of course leopard will boot it is a universal binary just like tiger.

Actually, Tiger had separate PPC and Intel installers.

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And yeah, it would mainly work with just the PowerPC code because of the kernel still being there and Rosetta.

Incorrect.
Rosetta is a separate installation and stand-alone code. If the Kernal were PPC code alone, an Intel machine can't boot it.

Jethryn Freyman
Dec 12, 2012, 04:13 AM
Actually, Tiger had separate PPC and Intel installers.

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Incorrect.
Rosetta is a separate installation and stand-alone code. If the Kernal were PPC code alone, an Intel machine can't boot it.

Not sure about either way... I have a set of 4x CDs with Tiger 10.4 that are PPC only,I also have grey machine-specific discs that are a specific 10.4.x version only that are Intel-machine only... I can't actually recall seeing a universal 10.4 Tiger installer. Even my 10.4.11 combo update I have saved is PPC only.

justperry
Dec 12, 2012, 04:39 AM
Monolingual does not trim OS code. Its blacklisted in the program settings.


Also, to trim the kernal would require that you decompile and recompile it.

Nonsense, see screenshot, mine is PPC only, actually whole my system is PPC only.
You can strip the code of everything with a simple: sudo ditto --rsrc --arch (architecture to keep)ppc In my case PPC.
Left is a stripped kernel in Leopard(Boot Volume), right is a clean kernel in Leopard.(5 MB v 9.9 MB)

To the OP, if you completely strip ALL Intel code it will NOT boot on Intel.

SuperCyborg
Dec 12, 2012, 07:28 AM
actually whole my system is PPC only.

Is it as blissful as they say?

Jessica Lares
Dec 12, 2012, 07:35 AM
Not sure about either way... I have a set of 4x CDs with Tiger 10.4 that are PPC only,I also have grey machine-specific discs that are a specific 10.4.x version only that are Intel-machine only... I can't actually recall seeing a universal 10.4 Tiger installer. Even my 10.4.11 combo update I have saved is PPC only.

http://lowendmac.com/ed/rosen/09ar/install-mac-os-x-tiger.html

The ability to install, reinstall, or upgrade to Tiger remains important, but it is increasingly difficult. Mac OS X 10.4 installers have been discontinued by Apple and are no longer sold at retail. Finding an installer requires buying a new or used copy from a reseller - or borrowing a copy from a friend, consultant, or other Mac user.*

To increase the challenge, there are different versions of the Tiger installer for PowerPC and Intel Macs. Apple never released a Universal Binary of the full installer, instead releasing separate PowerPC and Intel versions. Some later updates were available as Universal Binaries, but not the full OS installers.

Every Mac sold during the Tiger era came bundled with a grey Mac OS X installer DVD. These discs will reinstall the OS on that model of Macintosh, but they may not work with other Macs using the same processor. There is (I'm sure) an underlying consistency to what discs will work with what models based on system architecture, but these relations are often not user discernible. On practical level, it's usually a trial-and-error process if you don't have the right disc.

On the PowerPC side, the situation is easier. Apple sold several versions of Tiger at retail, culminating with a 10.4.6 full install DVD. These discs will work on all supported models of PowerPC Macs and are the best ones to have or try to find via resellers. The bundled install discs that came with G4 and G5 Macs do not work across the board on all models - again trial-and-error.

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All Intel Macs came with their own (grey colored) Tiger install DVDs. Apple never sold a Full Installer for Tiger that was Intel-compatible. No need - if you were buying an Intel Mac, you automatically got Tiger, and if you had a PowerPC Mac, you wouldn't need an Intel-compatible installer (nor could you use it).

This makes sense - until you need to reinstall Tiger on an Intel-based Mac. The original Intel iMac, MacBook, MacBook Pro, Mac Pro, and Mac mini models (which came with Tiger from the factory) all use different custom install DVDs. Most systems require their own discs, again hit-or-miss will apply.

I have had luck using the 10.4.10 installer that came with my Mac Pro to reinstall Tiger onto an early MacBook, but a MacBook Pro installer from the same era didn't work. You do need the original discs - just at the moment (of course) when you can't find those little envelopes that came bundled with the snazzy Apple cleaning cloth and window stickers you safely saved for future use.

Yes, you know they're around somewhere....