6502 -> 680x0 -> PPC601 -> x86 -> x86_64 -> ARMv8.5 (Apple M1)

The original Intel Mac's ran the 32-bit Core Duo, although a mid-season refresh took them to the (64-bit) Core 2 Duo. That generation of purely-32-bit hardware being out in the wild had some real impact on moving the OS forward, later down the road.

I completely forgot about the Core Duo Mac Mini!

We had purchased one, when 10.5 released. And it died shortly after to be replaced by the Core 2 Duo Mac Mini. The x86 era was so short I barely remembered it.

Hey don't forget the poor old Apple ///, Apple //e, and Apple //GS! ;)

6502 -> 6502B -> 65C02 -> 65C816 -> 680x0 -> PPC601 -> x86 -> x86_64 -> ARMv8.5 (Apple M1)

Beat me to it!

Also probably worth dividing PPC into the 32-bit architectures (601, 603, G3, G4) and 64-bit architectures (G5), although the PowerPC architecture did that transition in such a civilized manner that it wasn't really traumatic. In some ways the jump from the 601 (Power-ish) to 603 (true PowerPC) was bigger than the jump from the G4 to the G5.

They also never fully went 64-bit on PPC, so there was never really a transition there, just some 64-bit machines that could do some slightly different things and I don't think there was ever a full 64-bit version of OS X for PPC. So there weren't any huge painful breaks.

Good points. Worth noting that PPC -> x86 was a 64 bit to 32 bit transition.

I assume we will soon see ARMv8 -> ARMv9, but that will hardly be noticeable.

I owned the first MacBook Pro but it died before the architecture became an issue :(

Overall Apple should be good at architecture transitions by now as they've done enough of them!

Also the jump from 68000 and 68010 to 68020-030-040 had a similar transition (if anyone remembers having to worry about wether your software/system was 32 bit clean)

6502 was only used in the Apple II and MacOS never ran Apple II software on its 68k processor, so it doesn't really belong in that list.

Indeed . You could run Apple II software on an add in card though.

https://en.wikipedia.org/wiki/Apple_IIe_Card

I thought about mentioning it but that doesn't really count as a transition like the others. You could not even run the card and MacOS simultaneously:

> When emulating the Apple IIe, only a full-screen mode is available and all native Macintosh functions are suspended while running (a proprietary graphical control panel, running outside MacOS, is available for configuring the virtual Apple II slots and peripherals; however, both native and emulated computer function are suspended during this activity). Macintosh functions and control resume only once emulation is completely shut down and exited.

Arguably, the transition from MacOS to Mac OS X does belong in the list. Apple did a ton of work to provide the Carbon compatibility layer to make it easier for developers to port to Mac OS X. And there was also the ability to run MacOS 9 under Mac OS X using Classic.

Agreed. It is sort of helping users to make the move though.

It's almost like a reverse transition: instead of getting a new cpu and making it work with the old ecosystem and software you take an old cpu and software and and get it to work with the new hardware (I know the analogy isn't perfect!)

No fair. But it FUNDED the start of that list! ;)

> I'm actually more surprised about the iPad Pro going from the A-series to the M-series

M1 is more or less a "A14X" so that doesn't really surprise me that the iPad Pro would get an -X tier chip.

Almost!

6502 -> 680x0 -> PPC601 -> x86 -> x86_64 -> ARMv8.5 (Apple M1)

First Intel Macs (MacBook Pro) had a Core Duo which was 32 bit. I think Core 2 Duo was delayed and Apple weren't particularly happy about it.

There was a Core Solo mini as well at the bottom end of the line.

Indeed: Core Duo with one core not working / disabled.

And to add to the growing list of CPU transitions, don’t forget the NeXT heritage which included its own support of Motorola, Intel, PA-RISC and SPARC