When it releases iOS 9, Apple will make updating easier for owners of 8GB and 16GB iPhones and iPads. As Andrew Cunningham reports for Ars Technica, the company has already announced that the main iOS 9 update will need only 1.3GB, much less than the 4.6GB needed to update to iOS 8.0, and noted that “App Thinning” technology will reduce the amount of space that apps take up in iOS 9. The company has sent out its first update to the iOS 9 developer beta, and, as spotted by iOS developer Kaleb Butt, the operating system can offer to temporarily delete apps to make room for the update. It will automatically re-download them when the update is complete.
Deleting an app from your iPhone or iPad would normally remove the app’s saved data and settings, as well. Cunningham notes that Apple has, presumably, either come up with a way to prevent that from happening, or is using iCloud to back up and restore the data along with the app. It’s unclear whether your iPhone or iPad could delete and restore things like locally-stored music or videos from iTunes to make room for the update. But even if iOS 9 can only delete apps, that’s likely to be enough to free up the space that the iOS update requires.
Cunningham notes that it would be ideal to see Apple upgrade the amount of storage space that comes with its entry-level devices. But for users who already own an iPhone or an iPad with a low amount of internal storage, the changes Apple introduces with iOS 9 should take care of one of the biggest annoyances users experienced when trying to upgrade to iOS 8.
Ars Technica reported that at its annual Worldwide Developers Conference, Apple gave its transformative “app thinning” technology only a passing mention. But iOS 9 brings three different mechanisms by which developers can make their apps smaller. The first, App Slicing, is the most significant. Each iOS app binary that you download contains code for a variety of devices; in fact, an up-to-date app contains assets for every supported iOS device, whether your device needs the code or not. App Slicing will enable your device to download only the code that it needs, without requiring much extra work of app developers. The App Store itself will do the work of compiling and delivering device-specific versions of a developer’s apps.
The second feature, called On-Demand Resources, refers to chunks of apps that are only downloaded to your device when you need them, and then are cleared from your device when you’re done with them. In a game, for example, the app only needs to have data for the level you’re currently playing and the levels that immediately follow it.
Or in an app with a tutorial, your device could download the assets for the tutorial the first time you use the app, and then delete them when you don’t need the tutorial anymore. To take advantage of ODRs, developers need to assign different tags to different chunks of code, and they’ll be able to specify what code is needed for an app’s first launch and which tags should be deleted first if the device needs to free up some space.
The final feature, called Bitcode, changes the way developers upload apps to the App Store. Instead of submitting pre-compiled binaries, they’ll upload an “intermediate representation” of an app, which will be compiled on-demand specifically for the device that’s downloading it. That enables some of the App Slicing functionality, since it determines whether you need a 32-bit or 64-bit binary.
As Juli Clover reported for MacRumors, the second beta of iOS 9 also revealed a number of other performance improvements, feature updates, and bug fixes. Among those are an updated layout and icon for the Podcasts app, the appearance of Handoff in the App Switcher, improvements to Search, the renaming of the Apple Watch app to “Watch,” News settings under iCloud, Search settings, iPad keyboard tweaks, and new settings for Safari.