[dwaite]

Yeah, unix usually is based on reactor pattern async I/O, while IOCP is proactor pattern.

You can build a proactor pattern on top of a reactor pattern, but that implementation needs to provide quite a bit - more coordination of pending memory/state and probably needing back pressure support (which I never really understood if Microsoft supplied or if you had to track that yourself).

I know Microsoft used to have several IOCP-related patents; I believe I remember one for event scheduling for multi-threaded locality (preferring to dispatch a completion to the same thread that made the original request).