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Imac g4 and system 7.6.1

Cory5412

Daring Pioneer of the Future
Staff member
iMac G4s will need either OS 9 or OS X.

Your best bet for a 7.6.1 system will be something along the lines of a 7x00/8x00/9x00 Power Macintosh.

 

Anonymous Freak

Well-known member
No. The very earliest model of Power Mac G4 requires Mac OS 8.6.  Some of the latest models can't even run OS 9.2.2 natively, only OS X.

Even the first generation of beige Power Mac G3 and the first Kanga "PowerBook 3500" PowerBook G3 require Mac OS 8.0 or later.  (Although through some hacking, it has been claimed possible to get the Kanga PowerBook G3 to run 7.6.1. I haven't seen any writeups showing how to do it.)

To put it simply, no Apple "Gx" machine can run any version of System 7 without hacking.  And even then, it's only the very first G3s.  Even the first iMac G3 can't run 7.6.1.

 

IPalindromeI

Well-known member
It's because they don't support USB, New World booting, Gx CPUs, the chipset, and various other important things.

 

bunnspecial

Well-known member
AFAIK one of the reasons for this is they don't have AKB ports and only OS 8.6 has support for USB at boot. 
The original iMac I think shipped with 8.1(or some variation thereof) so 8.1 does have native support for USB. In addition, I know the B&W G3 shipped with 8.5.5(my first came with the original install and the restore disk) and also shipped with a USB keyboard. The main significance of 8.6 is that it supports USB mass storage devices(flash drives, etc) which aren't supported in earlier OSs although things like USB floppies and LS-120s work. Just in case, though, the B&W DOES have ADB(so does the Yikes! G4, although it only has the solder pads on the board).

My rambling aside, though, I agree that the most painless way to run 7.6 is on an x500 or x600 machine. As far as I know, it will even run fine with a G3 or G4 upgrade card. I really need to test my 8600 with a G4 and see if it will boot in 7.6 so that I can say that definitely.

 

Cory5412

Daring Pioneer of the Future
Staff member
8.1 from Apple's special install CD that shipped with the iMac 233 Rev A has support for USB.

8.5 on the Blue-And-White G3, same story.

USB in 8.6 is said to work much better, but I haven't personally tried it out, as on machines where I wanted to use USB a whole lot, I went all the way up to 9.x.

G4 upgrades do work in PCI Power Macs (7000/8000/9000) with 7.5 and 7.6 on them. I don't know if most need extensions to work properly or not. I believe G3 upgrades in the PCI Performas (5000/6000 series) do need an extension to work.

 
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Compgeke

Well-known member
G4 upgrades in the PCI macs with a slotted CPU don't strictly need an extension but afaik the cache on the upgrade won't work without one. Motherboard cache should still work fine (but slower than the G4's cache). There shouldn't be much of an issue with extension support with G4s upgrades and OS 7 though, even the Sonnet 1 GHz G4s have support. At the same time, OS 7 doesn't support Altivec, at all, so there's little reason to actually use 7 on a G4.

The cache slot upgrades in something like a 6400 or one of the even more odd PCI slot ones do require an extension to be enabled. Being as the CPU isn't fully replaced in them you load the OS on the integrated CPU then it eventually switches over to the upgrade once you get the stuff loaded.

 

bunnspecial

Well-known member
8.1 from Apple's special install CD that shipped with the iMac 233 Rev A has support for USB.

8.5 on the Blue-And-White G3, same story.

USB in 8.6 is said to work much better, but I haven't personally tried it out, as on machines where I wanted to use USB a whole lot, I went all the way up to 9.x.

G4 upgrades do work in PCI Power Macs (7000/8000/9000) with 7.5 and 7.6 on them. I don't know if most need extensions to work properly or not. I believe G3 upgrades in the PCI Performas (5000/6000 series) do need an extension to work.
I do run 8.6 on some lower spec systems like early trayload iMacs, as I find that the smaller resource footprint makes them a lot more responsive while still retaining support for Classilla and flash drives. I DO run 8.6 on a lot of OWR low spec systems-I need to downgrade my 6500.

Aside from that, I'm mostly in agreement on 9.x on USB systems. I also run it on x600 series systems, which I find are more capable of handling resource-hungry OS 9. My regularly used 9600/200MP, for example(with 1.5gb of RAM and a Radeon 9200) is very peppy on 9.2.2. Yes, it does have USB. My Kanga and 3400C-from the same era-run 8.6(I have the RAM maxed at 160mb on the Kanga, but I still feel like it's not enough).

 
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