It wasn't IBM - IBM actually made fun of virtual memory while their engineers caught up with the competition.
I know that the RCA Spectra series had virtual memory in the 70's. The Spectra series was a 360 clone with the same instruction set. RCA developed virtual memory and converted their TSOS (Time Sharing Operating System) to VMOS. Univac bought the Spectra line and converted VMOS to VS/9. I worked for Univac at the time.
Virtual memory may have been used earlier by the Scientific Data Systems (SDS) Sigma series, later bought by Xerox. I was once a peripheral device to a Sigma, hooked up for an ECG.
I believe it was Burroughs who first did virtual memory. This was before the IBM Model 67 and the research at University of Michigan.
So my first major gig was a startup called Telemed located first in Park Ridge then in Chicago, in an office building at the end of runway 27 L. We built this system of collecting ECG data over the phone line in three-channel FM, converted to digital and then processed by Sigma 5! Sounds like the same system that you were hooked up to. How about that.
The Sigma5 didn't have virtual memory, but the Sigma 7 did. But this was well after both Burroughs and IBM had commercial offerings.
The Sigma series was produced by Scientific Data Systems, later bought by Xerox. Made Max Plaevsky the largest Xerox until Xerox bought University Microfilms.
I think, the Atlas was the first machine to support virtual memory (https://en.wikipedia.org/wiki/Atlas_%28computer%29), but I am not entirely sure when Burroughs first released a machine with virtual memory. Atlas was - according to Wikipedia - first operational in 1962.
