Running and serving (Hetzner Arm): http: https://swiftos.tech/

Announcement: https://forums.swift.org/t/swiftos-a-from-scratch-kernel-and...

Separate address spaces, kernel TCP/IP, SMP, filesystem. Arm-64 only. Working on drivers as restartable userland processes. POSIX-inspired but not Linux ABI-compatible.

A testament to what can be done by reducing requirements to the essentials.