Comment by mrpippy
18 hours ago
I believe it was the first RISC that Apple prototyped building a Mac around, including a 68K emulator. IIRC from Gary Davidian’s CHM oral history, it was corporate dealmaking that led to AIM and PPC more than any technical negatives for the 88K.
https://computerhistory.org/blog/transplanting-the-macs-cent...
Yeah, this is probably closest to the right answer. Apple DID choose the 88K, and then changed. Reportedly they put some 88K systems in a Mac chassis.
I do wonder what the exact reasons were. Maybe the PPC (complete systems) could be made cheaper? Maybe Apple was worried about relying on a single vendor? I am kind of skeptical of the “corporate dealmaking” angle, because it seems like there are valid technical reasons to NOT choose the 88K. Namely, that it requires companion chips, and the whole system (board + chips) ends up being complicated and expensive.
What I always read was that Apple did not want to be stuck relying only on Motorola again like they were with the 680x0. And it worked out, kinda, Apple had IBM to rely on to make the G5 (until IBM also lost interest)
I remember reading that the successor 88110 design with the support chips integrated was announced mainly to woo Apple but I don't know how true that is.
Bitsavers have some documents about the Jaguar RISC project[1] that do indicate Apple's feedback went into the 88110, for example in the System ERS it states "The main processor for the Jaguar is a new version of the Motorola 88000 family which has been enhanced (with input from Jaguar's team) in several areas over the existing implementation. This processor (which will be the MC88110) will be referred to as XJS in the ERS.". There's also an architecture document describing changes Apple wants to make to the 88000 ISA, although I'm not sure how much of this actually got through into the final 88110 (Apple wanted to break binary compatibility, not sure if that happened).
[1] The high end RISC machine project that went nowhere, which AFAIK became known as Tesseract when switched to PPC before it fizzled out.