[trentnelson]

None of the UNIXes have the notion of WriteFile with an OVERLAPPED structure, that’s the key to NT’s asynchronous I/O.

Nor do they have anything like IOCP, where the kernel is aware of the number of threads servicing a completion port, and can make sure you only have as many threads running as there are underlying cores, avoiding context switches. If you write your programs to leverage these facilities (which are very unique to NT), you can max perform your hardware very nicely.