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0 pointsjamestnz10y ago0 comments

According to the release notes for Safari 9 [1], it's because of performance concerns: "Apps containing content blocking extensions for Safari on iOS are available only on 64-bit devices, due to performance limitations of 32-bit devices"

I imagine there's no real reason that content blocking shouldn't work on 32-bit devices, but that Apple are trying to hit certain minimum performance numbers (for marketing/brand purposes)... and I'm sure they won't be upset if this should happen to encourage a few users of older devices to upgrade (i.e. forced obsolescence).

I think there are various examples of Apple doing this kind of thing (saying a certain generation of hardware is supported by software X, but then you find various things are disabled for you). Not exactly the same, but pre-2011 Macs cannot mirror their display via AirPlay (Apple saying the video hardware isn't up to the task) -- at least not until you install the third-party app AirParrot, then it works fine.

[1] https://developer.apple.com/library/prerelease/ios/releaseno...

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ytch10y ago

Maybe 32/64 bit isn't the issue, Apple just choose it as a flag to exclude slow CPU?

choppaface10y ago

The 64-bit CPUs have a wider (and thus effectively faster) bus, and content blocking is probably rather strenuous on CPU cache (lots of string/pattern matching?). While the 64-bit cutoff is likely mostly a marketing artifact, content blocking on 32-bit CPUs could actually be 2x slower or worse than 64-bit CPUs and thus make page rendering times very painful for some sites.

Yetanfou10y ago

Nope, it is pure marketing. There is no technical reason whatsoever for ad-blocking to require a 64 bit CPU or databus. It actually works fine on a single-core sub-Ghz ARM7 like that used in my phone (Motorola Defy) with all of 512MiB of memory.

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