Yes you read that right! They released it last moth on the computer history museum site, along with word for dos text editor software. You can compile and build this OS but can not release it for commercial use, this was done as a "starting" point for upcoming programmers to learn how personal computers are made. Lots of funny readmes by microsoft employees!


PRINT
        The infamous background file  printing  utility  which
        fools you  into  thinking  MS-DOS  can do something it
        really can't.
               - from a readme in MS-DOS 2.0


Programed in ASM.

Sweet! Now everyone can make a dos-based operating system. Of course x86 asm is not for everyone. I am having a hard time understanding it myself.

Yep that's very cool for those who want to study and mess with x86 asm.

This is cool! I might have to dust off my limited x86 knowledge and see if I can understand it!

This is really cool. Someone could indeed make a new GUI for DOS, or a new OS based on it. In regards to DOS being 16 bit, I think it might've made a 32 bit released before it was discontinued. The x86 architecture is backwards compatible anyways IIRC. In fact, you can actually upgrade windows from a very early version to windows 8 even on modern machines.

If an old version of Windows that is 16 bits works on a current generation machine (which I've seen in a Youtube vid) this would suggest that modern PC's do indeed support 16 bit mode.

This is pretty awesome, but that is a lot of assembly

Judging from the terms you may not distribute ms dos nor derivative works, so if you make a gui for it it will be only for you to use.

Well, you could make it into a patch, then you are free to distribute it.
This can even be done in an installer that automatically downloads DOS and applies the patch.