December/January 1987 I was doing a vacation EE internship in a power station in Australia. Some of the Hitachi mini computers still used core RAM. This was in an all Hitachi Heavy Industries turnkey coal-fired power station commissioned ca. 1985. Pretty sure they had a reference design from boilers and turbines right down to the hardware and software level and kind of cookie cutter stamped out power stations from it. The Hitachi engineering attitude was obviously "If it works, keep doing it the same way for as long as possible". I was told that for some software (firmware?) updates, they'd simply ship out a new core RAM module -- It's non-volatile after all.