On Tue, 23 Mar 2021, Brad Boyer wrote: > On Tue, Mar 23, 2021 at 06:50:05PM +1100, Finn Thain wrote: > > Anyway, surely this test for CPU_68020 in Source/mmu_support.c in > > Penguin is bogus. This must have to do with some quirk of the Mac II > > logic board and not the type of MMU or CPU. > > > > So, why sort chunks by address on Mac II? Beats me. I guess I'll have > > to dig out my Mac II and try EMILE, which doesn't have that hack. > > Apparently there was a bug in the original Mac II ROM that couldn't > handle more than 4MB in bank A. That would mean that anyone who had more > than 8MB had the larger modules in bank B.
Right. And, of course, the original Mac II is not the only model where bank B might be larger than bank A. Also, I found that it's not just the IIsi that has a small bank A that's all soldered-in. The IIvi/vx and Quadra 700 are in the same category. It appears that both Penguin and EMILE are likely to disappoint on these systems. It's a pity bootloaders don't share more code. I think there's a good argument for fixing this in EMILE and then wrapping a MacOS GUI around it, that could supercede Penguin eventually.
