https://en.wikipedia.org/wiki/Dave_Cutler
Lots of great stories about him. One is recounted here:
https://capitalandgrowth.org/articles/930/xbox-co-founder-my...
Other well known kernels were also written by very small teams. The first Unix kernel was written by two people and the first Linux kernel was written by one person.
[1] https://en.wikipedia.org/wiki/Windows_NT#Development
[2] https://en.wikipedia.org/wiki/Windows_NT#Hardware_requiremen...
That's not how NT was seen at the time. It was quite bloated relative to other PC OSs. Of course modern OS features required a bit more overhead than the crazy world of windows 3.0.
My first experience with NT was NT 3.51 on a 32 MB machine. If I remember well, it didn't feel much slower than Windows 3.1. But finally having a PC operating system that didn't crash all the time really made development much more pleasant and productive.
32M was insane, probably out of reach of all but rich homes.
Only a few years later (1 or 2) a classmate told us he had a computer with 128M. That sounded so ridiculous that we thought he was a mythomaniac or something. Turns out his dad was able to get a powerful workstation from work, and the first time we visited him we saw that mythical beast, and our mind were blown.
And right now the private working set of my start menu process is 27M...