The people who designed Mach in 1985 would almost certainly design something very different if they had today’s hardware, AI agents, secure enclaves, NPUs, ubiquitous networking, cloud edges, wearables, smart home devices and generally device density per person.

HarmonyOS is interesting because it points at the right axis: one coherent OS fabric across many devices, not a set of separate device OSes glued together by continuity features. Continuity, iCloud, Handoff, AirDrop, HomeKit etc are impressive glue. They are not the same as one logical OS fabric.