If I were so motivated, I would start with the principles outlined in https://en.wikipedia.org/wiki/THE_multiprogramming_system https://en.wikipedia.org/wiki/TH

If I were so motivated, I would start with the principles outlined in https://en.wikipedia.org/wiki/THE_multiprogramming_system https://en.wikipedia.org/wiki/THE_multiprogramming_system. Using Windows NT or Window 95 as an inspiration would make the task much harder. NT is an absolutely massive, full features, in some sense, and extension of Vax VMS, which itself is extremely feature rich. I would take the challenge to build something that is the simplest thing that could possibly work.