you are wrong, VMS breath !
The PDP-11's (and PDP-8's) did not (at least in the late 70's) run VMS, they ran a group of OS's named RTS/E, RSX and Ultrix. Ultrix was a clone of Unix, which was born on At&t 3B systems, which were clones of PDP's.
The PDP (Peripheral Data Processors) were used in process control and industrial automation. They succeeded TI 960 in these applications. Universities and others used the larger boxes to run data centers, and there was a two-chip implementation called LSI-11 that was one the first "personal" computers. The process control application is what the Nuke industry is using them for, controlling the pumps, control rods, indicators and alarms of the melters.
VMS was a creature of the 1980's, living in VAX hardware. I am not even sure there was a PDP version of VMS, but I cannot say because I had moved on to the IBM 370 architecture, or at least the 43xx air-cooled variants. VMS was really for running data processing, either a data center or a PC ("everybody needs a little VAX"). When M$ abandoned OS/2, VMS was cloned into WindowsNT, later Windows2000 and WindowsXP.
You have not been corrected previously because all the programmers from that age who were not teenage hackers are Alzheimers or dead. You are an ignorant GenXY moron. Whine about the Boomers some more, we were Men with Wooden Pencils and Slide Rules who wrote for the Big (and Small) Iron.