<i>For that matter, it starts to make me wonder whether someone could do what Microsoft have done but in reverse on Linux! In other words, implement a translation layer that translate ntdll.dll function calls to corresponding kernel syscalls, then work backwards implementing each of the user mode subsystems. Maybe WINE has done this already?</i><p>I thought that <i>was</i> what WINE did.  WINE = WINE Is Not an Emulator.