Srouji runs what is probably the most important and least understood division inside the world’s most profitable company. Since 2010, when his team produced the A4 chip for the original iPad, Apple has immersed itself in the costly and complex science of silicon. It develops specialized microprocessors as a way to distinguish its products from the competition. The Apple-designed circuits allow the company to customize products to perfectly match the features of its software, while tightly controlling the critical trade-off between speed and battery consumption. Among the components on its chip (technically called a “system on a chip,” or SOC) are an image signal processor and a storage controller, which let Apple tailor useful functions for taking and storing photos, such as the rapid-fire “burst mode” introduced with the iPhone 5s. Engineers and designers can work on features like that years in advance without prematurely notifying vendors—especially Samsung, which manufactures many of Apple’s chips.

[…]

A former Apple engineer who worked on the [original iPhone] said that while the handset was a breakthrough technology, it was limited because it pieced together components from different vendors, including elements from a Samsung chip used in DVD players. “Steve came to the conclusion that the only way for Apple to really differentiate and deliver something truly unique and truly great, you have to own your own silicon,” Srouji says. “You have to control and own it.”

Say you then launch Videos and stream a five-gigabyte movie that was purchased on the iTunes Store.

The reported storage usage for the Videos app in Settings won’t increase at all.

But if you glance at the amount of free device storage reported in Settings, you’ll notice it has dropped by five gigabytes due to that streamed video being cached automatically by iOS, thereby taking up five gigabytes of ‘Other’ storage.

Because the amount of device storage wasted on the ‘Other’ category cannot be directly checked out in iOS, less experienced users may be left scratching their head, puzzled as to why their reported free storage isn’t higher.

[…]

The 291-megabyte difference between the 856MB seen in desktop iTunes and 565MB reported by my iPhone is actually caches for the songs I had streamed via Apple Music.

[…]

People who use iCloud Photo Library with the ‘Optimize iPhone Storage’ option may observe a similar discrepancy in the ‘Photos’ storage section between iTunes and iOS Settings, due to large caches of photos in device-optimized resolution.

In the electronics recycling business, the benchmark is to try to collect and recycle 70 percent, by weight, of the devices produced seven years earlier. Jackson says Apple exceeds that, typically reaching 85 percent, including recycling some non-Apple products that customers bring in.

[…]

Apple shreds its devices to avoid having fake Apple products appearing on the secondary market, Jackson said. The company is working on ways to reuse components in the future, she said, declining to elaborate.