That was probably "core" memory, the stuff they used to put in the mainframes of those days - I believe IBM 1401 and on up until the 370. Howibbly expensive. AFAIK, the unit record machines didn't have any, but I never worked on one or even saw one, so I could be wrong. On second thought, since the URMs could tabulate, they probably had a k or 2 of c-ram to hold the totals.