On Tue, Dec 11, 2018 at 11:57 AM Noel Chiappa <jnc@mercury.lcs.mit.edu> wrote:
    > we must have added PTY's of some sort

There is indeed a PTY driver; it has comments from BBN'ers who edited it, so
perhaps we got it from BBN.
Hmm, I could be mis remembering, but IIRC the original PTY driver goes back to the Rand and/or UofI for the NCP.  I suspect BBN got it from the Bruce Borden's Rand distribution tape which was 74 or 75, I think.  Named Piped were definiately a Rand-ism (they were originally called 'Rand Pipes') and were on that tape along with their Editor.

It's too bad Greg is not here to ask.    My memory and Noel may know by the IMP release dates, is that Rand was on connected before UofI.  But there were issues and somethings were not 100% until the UofI NCP; which was the first really complete NCP for UNIX.    I'm pretty sure that Greg's version went back to Bruce, as well as to BBN and Harvard and I would have assumes MIT also. 

I don't remember if the original Rand Pipes and PTYs were 5th or 6th edition originally.   I'm fairly sure, UofI's NCP was 6th edition but think that Rand goes back to at least 5th if not 4th.