Comment by adrian_b

The first few versions of Windows NT had a very strong API resemblance with VMS, which is why Microsoft settled to pay to DEC a 9-digit $ amount, to avoid a legal battle. Though eventually that deal was less advantageous for DEC than it appeared from the amount of money, because it included the support of Windows NT for DEC computers.

The parts of the initial Windows NT API that did not resemble VMS looked liked cleaned-up versions of the UNIX API, e.g. the functions for handling file and device I/O.

The central role of asynchronous I/O in Windows NT was inherited from VMS, which in turn had inherited it from the RSX-11M operating system for PDP-11 computers (Dave Cutler had a major role in the development of all these 3 operating systems).

Whether VMS => WNT is a joke like IBM => HAL, is anyone's guess. A more certain thing is that IBM was named such as to be a hyperbolic substitute of the name of its main competitor, NCR (National => International, Cash Register => Business Machines)