Mac OS 7.6.1 on a Beige G3

[croissantking]

Yesterday I experimented a bit with getting Mac OS 7.6.1 to work on a Beige G3. For novelty/proof of concept

I stuck the 770 System Enabler in a 7.6.1 System Folder and restarted. On boot I get the usual errors about the system not being compatible, but I skipped them by bringing up the NMI box and typing G. It then crashes shortly after with a bus error.

I tried replacing some resources (boot, gusd and gbly) from the OS 8.0 System File to no avail.

Just to get an idea, is this a realistic endeavour?

 

[Snial]

Yesterday I experimented a bit with getting Mac OS 7.6.1 to work on a Beige G3. For novelty/proof of concept

I stuck the 770 System Enabler in a 7.6.1 System Folder and restarted. On boot I get the usual errors about the system not being compatible, but I skipped them by bringing up the NMI box and typing G. It then crashes shortly after with a bus error.

I tried replacing some resources (boot, gusd and gbly) from the OS 8.0 System File to no avail.

Just to get an idea, is this a realistic endeavour?

Theoretically it's possible for a G3 to run 7.6.1.. hmm, do G3 upgraded 604e(v), 603e(v) or 601 Macs run 7.6.1? The G3 based StarMax 6000/266 XL which was previewed in MacUser UK in mid September 1997 was supplied with both 7.6.1 and a hacked version of 8.0.

 

[finkmac]

it's more of a question of ROM (and chipset) support. so mostly ROM... mess around with that and things should be easier.

 

[Daniël]

Theoretically it's possible for a G3 to run 7.6.1.. hmm, do G3 upgraded 604e(v), 603e(v) or 601 Macs run 7.6.1? The G3 based StarMax 6000/266 XL which was previewed in MacUser UK in mid September 1997 was supplied with both 7.6.1 and a hacked version of 8.0.

I know my 740 upgraded PM6500 can run it, even down to System 7.5.5.
As finkmac mentions, it's not the CPU itself, it's the rest around it that matters.

 

[croissantking]

Exactly, it'll be the logic board and chipset that'll matter. But, all of that should be supported by the System Enabler 770.

The first thing I'd like to do is alter the boot code so that it doesn't show an error about an unsupported machine. I guess it'll be a matter of editing a resource or two like getting a 68030-based Macintosh to boot Mac OS 8.

 

[croissantking]

The G3 based StarMax 6000/266 XL which was previewed in MacUser UK in mid September 1997 was supplied with both 7.6.1 and a hacked version of 8.0.

I just looked through the article. Did these ever get released to the public?

 

[finkmac]

I just looked through the article. Did these ever get released to the public?

nope.
i've spent some time digging through ancient sites and articles and i'm about 70% sure the starmax 6000 is a production version of the motorola "cobra" ref design.

maybe sometime i'll compile all the stupid trivia and infos i've found into something readable....

 

[croissantking]

From Macworld, October 1997:

 

[chelseayr]

might be offtopic but still, read on;

as I recall 7.6 was supposed to be updated one more time (after having had been 7.5x then before that 7.1, etc) but apple was starting to take a dim view of clones and not surprisingly one of the best way to work out the legalese was to simply not make it a number seven anymore .. and in the meanwhile the newer apple macintoshes being designed to come out soon were pretty much officially only for the number eight

and as far as I can recall right now, naturally no clones 'that was actually released to public sales' officially ever had a native G3 cpu for this reason as apple naturally refused to license macos 8 out to anyone

 

[Snial]

I just looked through the article. Did these ever get released to the public?

The front cover seemed to think it wouldn't happen and there was a paragraph about saying Apple wouldn't certify CHRP.

 

[bakkus]

might be offtopic but still, read on;

as I recall 7.6 was supposed to be updated one more time (after having had been 7.5x then before that 7.1, etc) but apple was starting to take a dim view of clones and not surprisingly one of the best way to work out the legalese was to simply not make it a number seven anymore .. and in the meanwhile the newer apple macintoshes being designed to come out soon were pretty much officially only for the number eight

and as far as I can recall right now, naturally no clones 'that was actually released to public sales' officially ever had a native G3 cpu for this reason as apple naturally refused to license macos 8 out to anyone

There was briefly a 7.7 beta, and it's on The Garden.
Could it contain any differences making life possible on a G3?

 

[NJRoadfan]

My G4 upgraded PowerSurge machines ran 7.5.3 and 7.6 without any problem. Its not the CPU.

 

[chelseayr]

@NJRoadfan hmm well..naturally because its still a pre-G3 logic board and everything? :->

 

[Arbee]

@NJRoadfan hmm well..naturally because its still a pre-G3 logic board and everything? :->

Right. The logic board is the issue, not the G3 (or G4!) CPU.

 

[croissantking]

Right! So we all agree: it’s the logic board
I’m guessing we will just need some minor tweaks to boot code to get this to work, as any custom drivers will already be in the System Enabler 770.

 

[KGLlewellyn]

I don't suppose you've tried adding MacsBug to your 7.6.1 install? I'm wondering if that would give us more information as to what is triggering the Bus Error?

 

[aladds]

I’m sure I’ve read before that the original Beige G3 was _officially_ 7.6.1 compatible. Maybe it needs a Rev A ROM?

Edit: well I’ve searched around a bit and there are a few references which suggest this is the case for early revisions. I actually have such a revision (RevA, RageII+) at my Mum’s house so when I visit over the holiday period I will take a pre-loaded BlueSCSI or something and try it

 

[croissantking]

I’m sure I’ve read before that the original Beige G3 was _officially_ 7.6.1 compatible. Maybe it needs a Rev A ROM?

Edit: well I’ve searched around a bit and there are a few references which suggest this is the case for early revisions. I actually have such a revision (RevA, RageII+) at my Mum’s house so when I visit over the holiday period I will take a pre-loaded BlueSCSI or something and try it

I have tried with a Rev A ROM but it was a no-go for me…

 

[croissantking]

I don't suppose you've tried adding MacsBug to your 7.6.1 install? I'm wondering if that would give us more information as to what is triggering the Bus Error?

I missed this, but good idea and I’ll give it a whirl.

 

[alectrona6400]

hmmmmm.... i dont know that i ever saw much of a point to this but its interesting. i have noticed OS 8.0 and 8.1 are much, much closer to 7.6.1 than 8.5 and later (which is PPC native, and also faster)
i know on 8.0 and 8.1 you can use the OS without appearance manager whatsoever, essentially making it 7.7.0 and 7.7.1 respectively.. but you'll need the control panels and a few extensions from 7.6.1; probably easier to import an 8.0/8.1 system file to 7.6.1, which works nicely too (might have bugs, after all its a hybrid setup!). i have seen the G3 is a new architecture compared to the 8600 and 9600 powermacs, so that could be an obstacle for sure which is to figure out how 7.6.1 can work on a new platform that apple likely did not account for with 7.6.1 during the development of the beige G3

just thought i'd give my two cents on this... if it can boot that would be really cool to see though, we got 9.2.2 and 8.6 running on unsupported macs (though that area is quite different), so its possible. it's already an old world system which makes it possible, because 7.6.1 on new world is very likely to be impossible due to the dependence of the mac OS ROM file that 8.1> have, but 8.0< do not...