So, in this 8.6 thread, in which we discuss Macs such as even the MDD booting 8.6, I wondered about G4 support for even earlier OSes, and got my mind blown after being told and shown 7.6.1 booting with a 1.0GHz 7455 G4 Sonnet CPU upgrade on a marvelous Macintosh clone. But after being enthusiastic about experimenting such things with my MDD, it occurred to me: "... MDD and all other G4 Macs are New World ROM machines.".
I instantly feared that alone could put a stop to all this, so I immediately looked up what the very first New World ROM Mac was capable of booting out-of-the-box. And the answer was the Blue and White G3 Tower. It had two releases, the first of which came pre-installed with Mac OS 8.5.1. This means a ROM file for booting Mac OS on New World ROM machines exists at the very least for Mac OS as far back as 8.5.1, which is excellent, and very surprising, news.
Now, "why surprising?", you may ask. That's because the jump from Mac OS 8.5.1 to Mac OS 8.6 changed the operating system's nanokernel from v1 to v2, which was a complete revision of the OS kernel, which was a BIG change. For one thing, the v2 kernel is actually capable of pre-emptive multitasking (although it runs all Mac OS tasks, so-called "blue tasks", within a single task for backwards compatibility with apps, thus providing the co-operative multitasking environment within a pre-emptive one), there was some AltiVec support (which was fully complete starting with Mac OS 9) and so on.
So for whatever it is worth, it seems at least Mac OS 8.5.1 on MDDs and other G4s might be possible, provided we track down:
- The original Blue and White G3 Mac OS ROM file;
- The original Blue and White G3 OS Restore disc(s) (just for good measure, in case there was a special version, just as how 8.6 had a special G4 version for the Sawtooth).
By using a SATA PCI card (which emulates SCSI, and is seen as a SCSI device by Mac OS) to avoid risks of IDE incompatibility (such as the case with Mac OS 8.6 with MDD's ATA-100) and an early PCI graphics card, minimal RAM and about nothing else plugged, we might be able to pull something off. Some minor OpenFirmware changes might also be necessary, as with the case of Mac OS 8.6.
Just sharing thoughts, and seeing if anyone feels like beating me to the punch, as I might take some time before I try this. But I wanted to at least get the idea out there right away.
I instantly feared that alone could put a stop to all this, so I immediately looked up what the very first New World ROM Mac was capable of booting out-of-the-box. And the answer was the Blue and White G3 Tower. It had two releases, the first of which came pre-installed with Mac OS 8.5.1. This means a ROM file for booting Mac OS on New World ROM machines exists at the very least for Mac OS as far back as 8.5.1, which is excellent, and very surprising, news.
Now, "why surprising?", you may ask. That's because the jump from Mac OS 8.5.1 to Mac OS 8.6 changed the operating system's nanokernel from v1 to v2, which was a complete revision of the OS kernel, which was a BIG change. For one thing, the v2 kernel is actually capable of pre-emptive multitasking (although it runs all Mac OS tasks, so-called "blue tasks", within a single task for backwards compatibility with apps, thus providing the co-operative multitasking environment within a pre-emptive one), there was some AltiVec support (which was fully complete starting with Mac OS 9) and so on.
So for whatever it is worth, it seems at least Mac OS 8.5.1 on MDDs and other G4s might be possible, provided we track down:
- The original Blue and White G3 Mac OS ROM file;
- The original Blue and White G3 OS Restore disc(s) (just for good measure, in case there was a special version, just as how 8.6 had a special G4 version for the Sawtooth).
By using a SATA PCI card (which emulates SCSI, and is seen as a SCSI device by Mac OS) to avoid risks of IDE incompatibility (such as the case with Mac OS 8.6 with MDD's ATA-100) and an early PCI graphics card, minimal RAM and about nothing else plugged, we might be able to pull something off. Some minor OpenFirmware changes might also be necessary, as with the case of Mac OS 8.6.
Just sharing thoughts, and seeing if anyone feels like beating me to the punch, as I might take some time before I try this. But I wanted to at least get the idea out there right away.
