Memory Tech you don't see very often

Brent Hilpert bhilpert at
Thu Jan 6 03:06:04 CST 2022

On 2022-Jan-06, at 12:19 AM, Joshua Rice via cctech wrote:
> Not cost effective at nearly $10,000! I understand they're very rare, given they were only used for a few years in industry and they're clocking on 3/4 of a century old, but even then, that seems an order of magnitude or two off the real value.
> Actually, looking them up, doesn't seem they were used in much at all. Seems to have been a bit of a technological dead-end since core memory quickly superseded it with it's (relatively) cheap costs and (relative) ease of manufacturing. I imagine the US gov. probably used them somewhere, since they were a sucker for cutting edge technology of the time.
> Would be interesting to know how many hours it's got on it

"Not cost effective" ?  What does that mean in the arena of valuation of historic artifacts?

No, they didn't go anywhere as a product and apparently only saw use in one machine.

However, the 'pro' side of such a debate is that they were a very early attempt to produce a fast digital RAM memory specifically for use in Stored-Program Machines, at a time when memory was at the top of the list of problems in development of the first SPMs, and actually before any SPMs had been produced, and weren't a serial technology like drums and delays lines tortured into applicability for the task.

They are wrapped up in the history of John VonN and the IAS machine, one of the most significant machines in computing history (arguably the most significant).

There's always opinion and subjective valuation in assessments of history but if one is acquainted with what was going on in that period of 46-50, they are a very interesting and notable development attempt.

> ------ Original Message ------
> From: "pbirkel--- via cctalk" <cctalk at>
> To: "'General Discussion: On-Topic Posts'" <cctech at>
> Sent: Wednesday, 5 Jan, 2022 At 17:35
> Subject: Memory Tech you don't see very often
> Selectron Vacuum Tube: <>
> Really nice photo-shoot! I wonder what the back-story to this particular
> tube might be.
> I don't think that $16.18 shipping would be, um, adequate protection by any
> measure.
> Cheap, but not so sure about "cost-effective" .

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