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Comment by Wowfunhappy | Hacker News Reader

So, do 4 KB page size apps work on these 16 KB page size phones? There are plenty of legacy apps (especially games I'd imagine) that will never updated for one reason or another. I would want to know if I was buying a phone that won't support those...

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That ship already sailed, most legacy Android games were killed by 32bit support being phased out both in hardware (newer SOCs are 64bit only) and software (Android 14 doesn't support 32bit apps even when running on an older SOC). They've done it before and they'll do it again.

Which is a shame, a modern SoC is fast enough to emulate 32-bit in userspace with same-or-better performance than the real 32-bit SoCs from that period.

>(Android 14 doesn't support 32bit apps even when running on an older SOC).

Completely untrue and can be entirely circumvented by one ADB flag (--bypass-low-target-sdk-block) or a third-party .apk installer.

In other words, completely true because this is HN and we know things that the other 99.999% of the world doesn't and never will and never even thinks to ask.

Instead, "Google took away my favorite software off my device that I paid money for, and fuck 'em for doing it" is a totally okay thing for normal people to do.

Fwiw when I asked the question I was specifically wondering if the apps will work at all, not whether they're easily accessible or easy to install.

And yet this issue is brought up by everyone often enough for there to be multiple YouTube guides, XDA threads and other sources of information explaining this to what you would probably call 'normal people'.

Well, I wouldn’t call it “completely” untrue if you need to use an ADB flag or third-party installer… most users will get apps from the Play Store and nowhere else

> Android 14 doesn't support 32bit apps even when running on an older SOC

Huh? Tell that to my phone. Maybe Google dropped support from their own OS builds even for older phones, but I don't think AOSP as such has dropped 32-bit-compatibility yet, and other OEMs have kept 32-bit-support for those phones whose hardware still supports it.

(And at least one or two Chinese OEMs have been shipping some sort of compatibility layer for phones without hardware support, though possibly only for the domestic market, not export models/OS builds.)

It's true though that Google isn't too heavily invested in binary compatibility for native code, though to some extent their hand might have also been forced by the SOC manufacturers, because apparently 32-bits hardware compatibility is more expensive to provide on ARM.

WearOS devices are still predominantly 32bit. Android hasn't stopped supporting those in any way. They are trying to entice phones to no longer support 32bit but the support on Android still exists.

There's probably something that'll break, but iOS switched to 16KB pages with zero publicity or warning and it caused very few problems. The vast majority of applications don't care about what the page size is at all, and cross-platform native code already has to handle different page sizes so hopefully people didn't do the stupid thing of hardcoding it for Android and only dynamically checking on iOS.

Isn’t the biggest issue that compiled binaries have segments aligned only to 4kb, and those segments must be on different pages (because they have different memory protections) and can’t be slid relative to each other? I’m not sure how iOS dealt with this (maybe arm64 binaries always had 16kb aligned segments?), but apparently this is an issue on Android and requires all binaries to be recompiled.

https://source.android.com/docs/core/architecture/16kb-page-...

> maybe arm64 binaries always had 16kb aligned segments?

Yes — because the move to 16k pages happened at the same time as the move to arm64.

The NDK is a well of surprises, when I used to do Android native, I always thought it was a kind of 20% project at Google.

I suspect it would depend on if they have problematic native code.

The executable format (if it’s native code) doesn’t actually specify what page size it wants right? So there would be no way for the OS to block 4 KB page apps.

I guess they could block stuff that targets an older API version, but that would block a lot of things that would otherwise work just fine.

The executable format defines a number of segments, which must be on separate pages because they have different permissions, and can’t be slid relative to each other. So the page size can’t be larger than the segment alignment chosen at link time, though it can be smaller.

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