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Comment by z9e | Hacker News Reader

I envision there being a lot of ARM support issues across apps that I rely on. We finally got over the keyboard drama, I don't have confidence this will go well either.

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Well they've already figured out multi-targeting in XCode and gave done this once before so I would imagine for a lot of developers it will just be a recompile.

I saw a really cheap MacBook Air deal the other day and was tempted until I saw they're i3 based. Assuming App support, I could see them replace that with an ARM based CPU without anyone noticing.

They've done this 2 to 5 times before, depending on whether you count the 32-bit to 64-bit conversions and iOS.

68k->PPC, PPC->PPC64, PPC->x86, x86->x86-66, arm->arm64

what is x86-66?

X86-64 is the 64-bit version of x86, also known as AMD 64 and Intel 64. The first computers that apple shipped with Intel processors only supported x86 (32-bit). The most recent version of macOS removed support for x86, only allowing 64-bit apps to run.

https://en.wikipedia.org/wiki/X86-64

Yes, but what is what is x86-66?

A typo

I'm not sure you could say they fully transitioned from PPC to PPC64, as only the G5s were 64bit, and laptops never got the G5. I think the x86 transition would have been easier if it started out 64bit, but that's probably Intel's fault.

More practically, the transitions so far have been like this: 68k -> PPC (With full 68k emulation) -> x86 (with partial PPC emulation) -> x86_64

Yes Apple has mastered multi-targeting. Apple has completed MANY major transitions 68k -> PPC -> Mac OS X -> Intel -> a near perfect 64bit transition.

Then there is the NeXT side that ran on 68k, x86, PA-RISC, and SPARC

Of course OS X was the foundation to iOS

I think the forced death of 32bit apps last year entirely in preparation for moving to ARM.

> I think the forced death of 32bit apps last year entirely in preparation for moving to ARM

You probably mean this is so they're not in multiple transitions at once. Something to note here is that Microsoft's x86 emulation only works for 32 bit apps (a processor limitation?), but with Apple having more control over their chips (and no knowledge about the exact issue) I could imagine them having it solved.

No, what I have heard from a Mac developer friend is that Apple's Xcode tool chain is likely able cross-compline x86-64 applications to ARM with relative ease. By forcing developers to move to 64bit last year, much of the work will already be done for the ARM transition.

(Of course, there are always difficult cases that will take lots of work)

You say it like it's a bad thing. I can't wait to have more competition as far as instruction sets go. Of course things will break but it'll give us a reason to make our apps and toolchains ARM-compatible beyond Raspberry Pis and small devices.

Is there a way to say "a lot of ARM support issues across apps that I rely on" as though it isn't a bad thing? Hahah. I do agree some instruction set competition would be a good thing, especially if this can further improve battery life on portable devices.

Depends on how fast they are and who knows, there might be custom hardware to help the emulation. I’m pretty sure while there will be issues 4-8h of battery life and your laptop working at full speed when not on the mains will be great wins and eventually worth the change.

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