From a Windows development point of view, Linux is way behind. Async I/O has been at the core of the NT kernel since the very beginning (since VMS, even), where

From a Windows development point of view, Linux is way behind. Async I/O has been at the core of the NT kernel since the very beginning (since VMS, even), whereas on Linux (and Unix) everything has been designed with blocking I/O in mind. IOCP match the way people usually think about asynchronous processing, but people have just become used to the weird way poll and epoll do things. It's like saying Windows is behind Linux because it doesn't support Unix permissions.