The Unix underpinnings, frameworks, and platform security model behind Apple's desktop OS.
The architectural reasons Apple's own dual-boot Windows solution didn't survive the transition from Intel to Apple Silicon, and why virtualization became the only realistic path to running Windows on modern Macs instead.
How Apple spent over a decade signaling the end of 32-bit app support before actually removing it in October 2019, and why the transition was smoother than it could have been as a result.
Released September 25, 2017, High Sierra automatically converted flash-storage Macs to Apple File System — the biggest filesystem transition on the Mac in nearly two decades.
Released September 13, 2000 for $29.95, the 'Kodiak' public beta gave Mac users their first hands-on look at preemptive multitasking, protected memory, and the Aqua interface before the final 10.0 release.
How the T2, introduced in the 2017 iMac Pro and rolled out across the Mac lineup through 2018, took boot security, storage encryption, and other sensitive functions away from the main CPU entirely.
The June 2019 WWDC announcement that Catalina would ship with zsh as the default login shell, and why an old GPL licensing decision, not a technical preference, actually drove the change.
The architectural reasoning behind Apple's multi-year push to deprecate kernel extensions in favor of user-space System Extensions and DriverKit, and what actually changes when a driver runs outside the kernel.
Why traditional plain-text syslog couldn't keep up with modern macOS's logging needs, and how the unified logging system's structured, activity-tracing design fixes the problems that made old-style logs so hard to use for real diagnosis.
Why macOS's kernel is neither a pure microkernel nor a pure monolithic kernel, and what that hybrid design actually buys in practice.
The inter-process communication framework behind most of macOS's privilege separation, built on Mach IPC but designed to make secure, sandboxed communication the easy default rather than an afterthought.