Wayne Beavers
You mentioned the early OSs for the 360, plus MFT. There was also PCP (Primary control program) and MVT (Multitasking with a variable number of tasks> I learned on PCP on a 128K model 40 running PCP at Cal Poly SLO in the early 70s. My first job was with Safeway (grocery store) running MVT on a 370 model 158. VM as added while I was there.