The so-called Columbus shared memory feature was in their system in the mid-1970s, along with a few other things such as semaphores and inter-process messages. I seem to recall the acronym MAUG, but I may have a letter or two wrong. Something like Multi Access User ____. The much later System V features had a completely different API.
Hey, Doug, do you remember this? In the early 1970s, there were a couple of UNIX meetings at Murray Hill, at which various Bell Labs groups presented on what they were doing with UNIX, and a group, perhaps Columbus, said that UNIX wasn't capable of doing what they wanted, so they had modified it. You asked the question, "Why are you using UNIX?"
To my knowledge, having witnessed another decade or so of groups trying to bend UNIX to their will, it was the last time the question was asked.
--Marc