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It certainly isn't arbitrary, macOS has swap and doesn't kill apps and iOS doesn't have swap and does kill apps. This makes everything very different, and one m
by astrange 3y ago
It certainly isn't arbitrary, macOS has swap and doesn't kill apps and iOS doesn't have swap and does kill apps. This makes everything very different, and one makes it easier to do real-time rendering than the other.
- eyelidlessness 3y agoI guess I should clarify. It’s arbitrary in that the restrictions are policy-based, not limitations of the underlying technology. There’s no technical reason iOS couldn’t have swap, it’s not available because trade off decisions were made to enable use cases on much more limited devices.
- MBCook 3y agoThe recent iPads based on M series chips now support swap. I think it was added in iPadOS 16 last year.
- astrange 3y agoIt's different-ish. iPadOS is still a more limited/controlled OS and the swap policy is also more limited. You can see it in the open source kernel where it's called "app swap", so it doesn't swap out the OS, but on macOS it can. "Limited" makes it, well, limited, but it has performance advantages: fewer unexpected page faults mean audio/video processes won't unexpectedly drop a frame as often, and there's fewer disk writes which is good for the lifespan of the hardware it runs on. Btw iOS actually has a very limited swap policy called "freezer" that only applies to suspended background apps, and only when it's in the performance budget.