3 ms·

Why would they need to emulate x86 they can just compile for ARM.

mattnewton 9y ago
They have to convince everyone else to as well though. There will need to be a transition period powered by emulation for third parties, similar to Rosetta from the last time they switched architectures.
- glhaynes 9y ago
  They’d have had a very hard time making the PowerPC -> Intel transition without Rosetta, but I’m not sure they’re in the same position now. How many apps on the average 12” MacBook are no longer maintained or have significant asm in them? I’d guess very few. Start with the MacBook and, over time, as Ax chips become faster and more software gets an ARM64 port, transition the whole line. (Not saying I’d bet on this scenario happening, but it doesn’t seem impossible like making the move to Intel without Rosetta would have been.)
  - MBCook 9y ago
    One of the important things about the Rosetta transition was that the x86 processors were DRASTICALLY faster than the G4s, especially in mobile. The difference wasn't as big on the G5 processors, but if you had an Apple laptop even after running through Rosetta the speed difference was noticeable. If they were to switch processors and it was only (say) 10% faster, the hit from the transition layer may make it a hard sell. Apple has been knocking it out of the park with the A-series processors though, maybe they could make a big enough difference that it would work out again.
    - silvestrov 9y ago
      There is another important difference: there was no GPU back then (and QuickDraw was not very suited to GPUs. OSX changed that). Applications where CPU time was mostly drawing on screen (e.g. text editors) worked a lot better than those where most CPU time was in app code. Today the GPU and graphics code is an even larger amount of the processing. So for a lot of apps it will not be a big problem if the emulation is a bit slow.
deleted 9y ago
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ender341341 9y ago
Apple doesn't have the same control of the app ecosystem on macOS that they do on iOS so they'ed need to maintain some compatibility system like they've done for their previous architecture migrations
daxelrod 9y ago
So that users can run all of their existing binaries. Both Mac processor architecture changes so far have included emulation or binary translation layers for this purpose. 68k -> PPC: https://en.wikipedia.org/wiki/Mac_68k_emulator https://en.wikipedia.org/wiki/Mac_68k_emulator PPC -> x86: https://en.wikipedia.org/wiki/Rosetta_(software) https://en.wikipedia.org/wiki/Rosetta_(software)
- ams6110 9y ago
  With NeXT they had "fat" binaries to handle different processors. No emulating.
  - rlanday 9y ago
    That does not solve the problem of existing binaries.

They have to convince everyone else to as well though. There will need to be a transition period powered by emulation for third parties, similar to Rosetta from the last time they switched architectures.

glhaynes 9y ago
They’d have had a very hard time making the PowerPC -> Intel transition without Rosetta, but I’m not sure they’re in the same position now. How many apps on the average 12” MacBook are no longer maintained or have significant asm in them? I’d guess very few. Start with the MacBook and, over time, as Ax chips become faster and more software gets an ARM64 port, transition the whole line. (Not saying I’d bet on this scenario happening, but it doesn’t seem impossible like making the move to Intel without Rosetta would have been.)
- MBCook 9y ago
  One of the important things about the Rosetta transition was that the x86 processors were DRASTICALLY faster than the G4s, especially in mobile. The difference wasn't as big on the G5 processors, but if you had an Apple laptop even after running through Rosetta the speed difference was noticeable. If they were to switch processors and it was only (say) 10% faster, the hit from the transition layer may make it a hard sell. Apple has been knocking it out of the park with the A-series processors though, maybe they could make a big enough difference that it would work out again.
  - silvestrov 9y ago
    There is another important difference: there was no GPU back then (and QuickDraw was not very suited to GPUs. OSX changed that). Applications where CPU time was mostly drawing on screen (e.g. text editors) worked a lot better than those where most CPU time was in app code. Today the GPU and graphics code is an even larger amount of the processing. So for a lot of apps it will not be a big problem if the emulation is a bit slow.

deleted 9y ago

[deleted]

ender341341 9y ago

Apple doesn't have the same control of the app ecosystem on macOS that they do on iOS so they'ed need to maintain some compatibility system like they've done for their previous architecture migrations

daxelrod 9y ago

So that users can run all of their existing binaries. Both Mac processor architecture changes so far have included emulation or binary translation layers for this purpose. 68k -> PPC: https://en.wikipedia.org/wiki/Mac_68k_emulator https://en.wikipedia.org/wiki/Mac_68k_emulator PPC -> x86: https://en.wikipedia.org/wiki/Rosetta_(software) https://en.wikipedia.org/wiki/Rosetta_(software)

ams6110 9y ago
With NeXT they had "fat" binaries to handle different processors. No emulating.
- rlanday 9y ago
  That does not solve the problem of existing binaries.