![](https://virtuallyfun.com/wp-content/uploads/2021/05/simple-c-program-with-October-1991-NT-SDK-for-OS2-2.00-v123.png)
So back in the day I wrote something vague about the October 1991 preview version of Windows NT, and after messing with the tools and building f2c & dungeon (among some other stuff) one that that stuck out to me is that the object files had to be converted for NT.
![](https://virtuallyfun.com/wp-content/uploads/2021/05/WindowsNT-3.1-October-1991-preview-simple-build.png)
The interesting thing is of course that it doesn’t support the cl386 direct compile and link (hence CL). Instead you have to compile, convert and then link. A fun thing about the October 1991 version is that there is a cl386 cross compiler for OS/2. So while looking around for OMF linkers (and assemblers that either understand GAS but output OMF, or some translator) I ran across this, and well yeah, it turns out that the OS/2 tool chain is the toolchain. I guess it makes sense in that the NT team was using OS/2 to build NT, but objects and exe’s were not solidified.
I think 6.00.080 was the last version of Microsoft C 386 for OS/2. I need to start collecting more of the SDK/DDK’s of the mixed era, I think the LX/OMF stuff was a bit more widespread hiding in plain sight.
Anyways, interesting?! sure. useful? Maybe 30 years ago. Although I’d probably say just use Watcom C/C++ instead of Microsoft C 6.00