On Fri, 2022-10-07 at 18:17 -0700, Chuck Guzis via cctalk wrote:
I recall that the IBM 650 had an upgrade option where core was used
for
some of the registers. It was small--maybe 50 words.
Until it moved from Sindelfingen to the IBM Tech Center in Böblingen,
the collection at Haus zur Geschichte der IBM Datebverarbeitung (House
of the History of IBM Data Processing) included a 650 in working order.
It belonged to a museum or university in Vienna and was returned when
the collection moved. I hope it survived the return journey. Hans
Spengler <hwspbb(a)t-online.de> was one of the staff who maintained the
650. He would likely know whether a core accessory had been available.