Those were at Berkeley. We've established that S-I&D were in V6 when it was released in May, 1975 - so my question is 'what was Bell doing in 1975 that needed more than 64KB?' The kernel, yeah, it could definitely use S-I&D on a larger system (especially when you remember that stock V6 didn't play any tricks with overlays, and also dedicated one segment - the correct term, used in the 1972 -11/45 processor manual - to the user structure, and one to the I/O page, limiting the non-S-I&D kernel to 48KB). But what user commands? It happens that I have a complete dump of one of the MIT systems, so I had a look to see what _we_ were running S-I&D on. Here's the list from /bin (for some reason that machine doesn't have a /usr/bin): a68 a86 c86 emacs lisp ndd send teco The lisp wasn't a serious use; I think the only thing we ever used it for was 'doctor'. So, two editors, a couple of language tools, an email tool (not sure why that one got it - maybe for creating large outgoing messages). (The ndd is probably to allow the biggest possible buffers.) Nothing in /etc, and in /lib, just lint1 and lint2 (lint, AFAICT, post-dates V6). Not a lot. So now I'm really curious what Bell was using S-I&D for. (If I weren't lazy, I'd pull the V6 distro - which is only available as RK images, and individual files, alas - and look in /bin and everywhere and see if I can find anything. I suspect not, though.) Anyone have any guesses/suggestions? Maybe some custom applications? Noel