Rupert Lane has started a blog series about Stanford's WAITS operating system for the PDP-10.
https://timereshared.com/stanford-waits/
https://timereshared.com/stanford-waits/
@larsbrinkhoff
From time to time I wandered onto the Stanford campus and used a freely-given account on WAITS. I thought it was supposed to be very much like ITS, but I found it confusing.
But I found ITS confusing too; I was a Unix guy in a strange land.
Later I spent enough time on TOPS-20 such that *it* was not confusing. It helps with operating systems to have lots of exposure, need to use, documentation, and community, in my experience.