Guys, maybe I am wrong, but according to Richard Petersen, the author of the well known "Linux: The Complete Reference" and some others (see Google) in 1973 Dennis Ritchi and Ken Thomas rewrote the UNIX code on C programing language. D.Ritchi, Thompson collegue in the Bell Labs created that programing language. The C lets to create a unifide version of UNIX which could be compilled to the different platforms. At 1980 Microsoft released version of UNIX for PC called Xenix..
So how C could be created for MS? Why programs written on C can not be or to be difficult to run on the C driven OS? Is not FreeBSD ( version of UNIX) used originally to create MS Windows?
In 1973 UNIX has been done on C. What is the first version of Windows and when it was released?