Editing IBM 1620 (section)

====The prototype====
The team expanded with the addition of Anne Deckman, Kelly B. Day, William Florac, and James Brenza. They completed the [[#CADET|(codename) CADET]] prototype in the spring of 1959.

Meanwhile, the [[San Jose, California]] facility was working on a proposal of its own. IBM could only build one of the two and the [[Poughkeepsie, New York|Poughkeepsie]] proposal won because "the San Jose version is top of the line and not expandable, while your proposal has all kinds of expansion capability - never offer a machine that cannot be expanded".

{| style="float:right;"
|-
| [[Image:IBM1620A.jpg]]
|-
| style="text-align:center;"| IBM 1620 Model I Level A (prototype), as it appeared<br/>
in the IBM announcement of the machine.
|}

Management was not entirely convinced that [[core memory]] could be made to work in small machines, so Gerry Ottaway was loaned to the team to design a [[drum memory]] as a backup. During [[acceptance testing]] by the Product Test Lab, repeated core memory failures were encountered and it looked likely that management's predictions would come true. However, at the last minute it was found that the [[muffin fan]] used to blow hot air through the core stack was malfunctioning, causing the core to pick up noise pulses and fail to read correctly. After the fan problem was fixed, there were no further problems with the core memory and the drum memory design effort was discontinued as unnecessary.