[Paladin2]

Bill didn’t want to have to go find some guy who had already written OS code to handle more memory space and was 32 bit compatible.

[Myrddin]

Gates hired the architect of Heathkit HDOS to be the architect for DOS. HDOS had loadable device drivers. I wrote a few myself. It was unsurprising to see the MSDOS has them too. I still have my paper copies of the HDOS source. It was a great way to learn how to do it right.