I was looking around for information on Lions’ Commentary when I came across this site which happened to be of a journalist who reviewed the Sun 2 workstation for the UNIX/WORLD magazine back in 1984.
The reference to a Sun employee demonstrating the dual head capability made me smile & reminded me of the Project Looking Glass demonstration.
What took me there was his derivative copy of the UNIX v6 source code but I also grabbed the v7 documentation which he posted up as updated PDF (changelog on the page)