For years, people have speculated about whether Apple would ditch macOS in favour of iOS, shedding desktops and turning laptops into something like an iPad Pro in a fixed clamshell. A version of iOS has apparently come to the Mac, but not in a way that anybody expected. The new Touch Pad has a separate brain, a custom T1 ARM processor system-on-a-chip (SoC), that looks to be running a stripped-down variant of iOS, possibly derived from watchOS.
Steve Troughton-Smith, an iOS developer known for deep examinations of how the operating system ticks, put the pieces together, some of which rely on information provided by Apple during on-the-record press briefings and on its site, and some from examining files within the newest release of Xcode, which allows developers to take advantage…