The history of RSX-11 is complex. First of all, what Dave Cutler did was
a redesign/reimplementation, which was RSX-11M. It is, from a user point
of view, very much similar to RSX-11D, which was the direct precursor.
Under the hood, the differences are much larger, however.
We also have IAS. And not to forget RSX-11A, RSX-11B and RSX-11C. But
they all came from RSX-15 (for the PDP-15), which was done by Dan
Brevik. Where the inspiration for RSX-15 came from, I have no idea.
But that don't change that it's Dave Cutlers name that is at the top of
just about every module in RSX-11M. He did a lot more that the I/O
subsystem there. Which was what the question was.
Johnny