Dennis stated the idea was not his, it came up during csonverastions at a conference.
Yeah that make sense. I'm pretty sure Joy had talked about it in the Summer '79 USENIX when 2BSD was announced. I remember his talk and a lot of people being awed (sort like what happens today when Linus comes to a conference). As I remember, one of his topics was csh and how it was different from the shell in the original BSD. He must have talked about #! and few other things for kernel (a bunch of speed ups in nami/inode look up IIRC), but that's about all I remember. The next winter was Boulder ('The Black Hole' conference) and he did a redux, and I remember being amazing how people were more interested in what he was saying than some of the folks from BTL and I remember a lot of Pascal questions at Boulder, FWIW. But to be frank, those conferences all sort of mix a little bit in my mind at this point.
IIRC: Dennis was there, Bruce Borden and the Rand folks, as were other folks like Chesson and some of the U of I folks. Thanks to my friendships with Ted Kowalsji and later Phil Karn, I had visited the labs a few times and had met Dennis et al in the early mid-70s, but I think that conference was the first time I personally met some of the other university types that I had been communication via the ArpaNet. I might even have an old conference list somewhere, but there was no proceedings yet for a few years.