Comment by jussij

The Win is just one layer in the OS/2 API and suspect you might be right in that this layer was probably modeled on early Windows.

However OS/2 had many other layers to it's programming SDK that were not found in early Windows.

For example there was the Dos layer for things like processes, threads, semaphores, files, directories etc.

And then there was the Gdi layer for graphics.

Most of that functionality only made it's way into Windows with the advent of Windows NT (Windows 3.x/95 had poorer versions of those functions. For example running a process and capturing it's output was a real pain in Windows 3.x and Windows 95).

And based on the fact so many of those OS/2 Dos function have an equivalent Windows NT version I suspect Microsoft used that OS/2 design as their starting point for NT.

As just one of many examples consider DosCreateThread from OS/2 1.x

http://www.edm2.com/index.php/DosCreateThread_(OS/2_1.x)

It looks a lot like the CreateThread function found in Win32:

https://docs.microsoft.com/en-us/windows/win32/api/processth...