OK. I'm totally confused, and I see contradictory information around. So I thought I'd ask here. PWB was started to support unix time sharing at bell labs in 1973 (around V4 time). PWB 1.0 was released just after V6 "based on" it. PWB 2.0 was released just after V7, also "based on it". Later Unix TS 3.0 would become System III. We know there was no System I or System II. But was there a Unix TS 1.0 and 2.0? And were they the same thing as PWB 1.0 and 2.0, or somehow just closely related? And I've seen both Unix/TS and Unix TS. Is there a preferred spelling? Thanks for all your help with this topic and sorting things out. It's been quite helpful for my talk in a few weeks. Warner P.S. Would it be inappropriate to solicit feedback on an early version of my talk from this group? I'm sure they would be rather keener on catching errors in my understanding of Unix history than just about any other forum...