[arcticbull]

Apple transitions CPU architectures every 10-15 years.

6502 -> 68k in 1984 via hard-cutover [edit: see cestith's reply, there's more to this story than I knew]

68k -> PPC in 1994 via emulation

PPC -> x86 in 2006 via Rosetta JIT translation

x86 -> ARM in 2020 via Rosetta 2 static recompilation

You could even argue the transition from Mac OS 9 to Mac OS X was a transition of similar magnitude (although solely on PowerPC processors), with Classic Environment running a full Mac OS 9 instance [1]

[1] https://en.wikipedia.org/wiki/List_of_macOS_components#Class...

[icedchai]

I disagree that 6502 -> 68k was a "transition." The Apple II and Mac were two separate product lines. The three major early home computer companies (Apple, Atari, Commodore) all did this.

[donarb]

Though Apple did sell a card that allowed 6502 apps to run on a Macintosh.

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

[icedchai]

This is true, but note it was released in 1991, many years after the Mac's introduction. By that time, the Apple II was definitely on the way out. The last hold outs (schools...) probably needed encouragement.

[cestith]

They also had the IIgs which was the 65c816 in 16-bit mode. The Lisa was in 1983 before the Mac, and it was a 68k.

[monocasa]

A 65c816 runs 6502 code natively.

[cestith]

Yes, in 8-bit mode. The IIgs runs with the processor in 16-bit mode from everything I've read about it. It might be able to swap modes to run older Apple software, but the IIgs is a 16-bit machine.