Re: Let's start a survey on our userbase

On 20205-09-23 at 18:03 John Paul Adrian Glaubitz wrote:
> I actually never thought about this but now you're saying it, it absolutely
> makes sense. Has it ever been confirmed that Apple shipped different versions
> of MacOS X with different PowerPC baselines?
AFAIK every installation CD or Boot-CD for Mac OS X works on every 
PowerMac, Power Book, eMac, iMac,...

If it doesn't work it's simply because a newer Mac would require drivers 
that are not there in older versions of Mac OS X.

Example: The Mac mini G4 from 2005 officially only supports Mac OS X 
10.3.7 and up, the Late 2005 however came with 10.4.2. I tested this 
thoroughly in the past and can confirm that it boots 10.4.0 as well as 
10.3.0, but with missing drivers.

I also tried 10.2.x on the Mac mini G4 and this also works. There is a 
driver from ATi for the Radeon 9200 and then this also works. Bluetooth 
and WiFi, but most important the throttling of the fan 
(thermal/energy/throttling management) doesn't work though. Again, lack 
of drivers, but overall it boots and works.

All my Power Mac G4s from 1999/2000 boot every Mac OS X for PowerPC that 
ever came out, including Mac OS X Server 1.0 (Rhapsody 5.3+) for PowerPC 
and including the unsupported Mac OS X Leopard (10.5) which requires a 
faster CPU.

Long story short: the ONLY ONE version of Mac OS X I know of that is 
specific to a certain Mac is 10.2.7 G5 (and the 10.2.8 update). Again, 
this is due to changed hardware as 10.2 only supported G3-G4.

Rhapsody is the only "Mac OS X" I know of that supports the G2 (PowerPC 
603) as well as the G3 (PowerPC 750). I've never tried the original 
Rhapsody 5.0/5.1 (that didn't support the G3) on a G3 or G4.

However, if I remember correctly, the big problem was Open Firmware. 
There are OldWorld- and NewWorld-Macs, and to get the operating system 
compatible with both was a "biggie". (I read in book somewhere that 
Apple spent quite some time to make the boot process stable.) The rest 
is CPUs and drivers. Naturally an OS for the G4 won't run on a G2 or G3, 
or even the original PowerPC 601, because of missing functions, but so 
won't Windows on a PC when the CPU lacks support. Example: Windows 7 x64 
used to run on Intels first x64-CPUs, but Windows 8 x64 wanted extra 
functions (specifically CMPXCHG16b, PrefetchW, LAHF/SAHF) and so this 
update stopped working e.g. on a PC of mine, because the Intel Pentium D 
8xx (Intel 64 supported) lacks PretechW and Windows 8.x/10 wouldn't 
start. An Upgrade to the Pentium D 9xx solved this. The same is true for 
newer Windows 11 builds, which also need a function in CPUs that is 
simply missing in older CPUs (Windows 11 24H2 requires SSE4.2).

TL;DR
No, with the one exception of Mac OS X 10.2.7 G5. There were OEM 
installation CDs/DVDs for specific PowerPC Macs, but this is always the 
same unmodified Mac OS X build, only with added drivers. Those drivers 
were then included in the next updated Mac OS X version, so the next 
generic Mac OS X installation disc will always boot on every previous 
Mac with G3, G4 and possibly G5 processor.

Cheers,
Mac User #330250