In a series of tweets sent out last night, and now in an interview with The Verge, developer Steven Troughton-Smith has detailed the inner workings of the MacBook Pro’s new retina Touch Bar, describing its T1 chip as “a variant of the system-on-a-chip used in the Apple Watch.” This means that the Touch Bar is essentially running watchOS on the T1 chip, which macOS then communicates with through an interconnected USB bridge that “relays multitouch events back to macOS.”
The developer described this software setup as advantageous for the MacBook Pro’s security, since the T1 chip also acts as a layer of protection and “gates access” to the laptop’s FaceTime camera and Touch ID sensor. In the series of Tweets he sent out last night, Troughton-Smith also theorized that watchOS could power the Touch Bar alone without relying on macOS to be running on the MacBook Pro, which Apple software engineering chief Craig Federighi has now confirmed.
You can theorise about the future here. Now that Apple has put an ARM iOS-like device inside every MacBook Pro, you can imagine a future wherein said iOS device takes over more and more functionality from the traditional x86 macOS device, up to a point where macOS only gets called upon when needed.
We may actually have just been given a hint of Apple’s transition-to-ARM strategy.