Tim Paterson has written some articles and appeared in some interviews, as the person who wrote QDOS for Seattle Computer - as a prototype for their new offering, ahead of a planned more substantial multi-user OS.
Articles and interviews at Paterson Technology.
Blog at DosMan Drivel “From the original author of DOS”
Digital’s CP/M-86 was in the air, and CP/M, as a proof of concept and as an API, was already popular.
(This is, of course, Tim’s telling of the story, hopefully containing some new and interesting ideas, but not necessarily matching up with everything we’ve read before.)
(As linked by Michal Pleban in his project blog mentioned in Homebrew Meets Business Computing)