IBM 1620; was: Early Programming Books

-----Original Message----- From: cctalk <cctalk-bounces at classiccmp.org> On Behalf Of Chuck Guzis via cctalk Sent: 21 June 2021 19:43 To: Paul Koning via cctalk <cctalk at classiccmp.org> Subject: Re: IBM 1620; was: Early Programming Books On 6/21/21 10:55 AM, Paul Koning via cctalk wrote: memory. Nobody explained why that was a real problem. > Core memory is fairly sensitive to temperature. In the case of the 1620, there is a heating system that brings the core memory box up to its operating temperature, which is why it takes several minutes after you turn on power before the machine will run. > Possibly the fan problem meant the temperature control system was no longer adequate. For some (jprobably hallucinatory) reason, I thought there was a project at CHM to replace the 1620 core stack with semiconductor memory. Guess that never happened. --Chuck