Im trying to find a post in HN about some OS developer in the 80s coding by hand

Hi, as the title says, I tried everything, checking my bookmarks and chatgpt but cannot find a post about someone telling the story of some engineer using pencil and paper for a month or so and then typing the code in one go and it worked flawlessly.

He was writing some niche OS system and the blog was a collection of posts about that system.

I also remember from the discussion thread that the developer had passed away.