The NPR.org news article and podcast How The World Has Changed! Science During The 40 Years Of 'Morning Edition' includes the photo below with the caption
Before the introduction of the personal computer, mainframe computers were the norm. The IBM System/370 mainframe computer, introduced in 1970, was one of the first computers to include "virtual memory" technology.
It says the /370 was "one of the first", and this answer to Did Cray computers use virtual memory? also mentions the /370.
Question: But was there a clear "first computer" to use virtual memory, or was it an incremental development with no clear first instance?
It may be helpful to differentiate the first commercial product from the first developmental demonstration.
Source: NPR, Credit: Getty Images