5 Jan
2022
5 Jan
'22
9:35 a.m.
Selectron Vacuum Tube: https://www.ebay.com/itm/174977901251
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" .
-----
6 Jan
6 Jan
12:19 a.m.
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quickly superseded it with it's (relatively) cheap costs and (relative)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
------ Original Message ------
From: "pbirkel--- via cctalk" <cctalk at classiccmp.org>
To: "'General Discussion: On-Topic Posts'" <cctech at
classiccmp.org>
Sent: Wednesday, 5 Jan, 2022 At 17:35
Subject: Memory Tech you don't see very often
Selectron Vacuum Tube: https://www.ebay.com/itm/174977901251
<https://www.ebay.com/itm/174977901251>
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" .
-----
1:03 a.m.
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been a bit of a technological dead-end since core memory quickly superseded it with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 classiccmp.org>
To: "'General Discussion: On-Topic Posts'" <cctech at
classiccmp.org>
Sent: Wednesday, 5 Jan, 2022 At 17:35
Subject: Memory Tech you don't see very often
Selectron Vacuum Tube: https://www.ebay.com/itm/174977901251
<https://www.ebay.com/itm/174977901251>
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" .
7:45 a.m.
There was also a 1K by 4 version of this tube.
On 1/6/2022 3:03 AM, Brent Hilpert via cctalk wrote:
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 classiccmp.org>
> To: "'General Discussion: On-Topic Posts'" <cctech at
classiccmp.org>
> Sent: Wednesday, 5 Jan, 2022 At 17:35
> Subject: Memory Tech you don't see very often
> Selectron Vacuum Tube: https://www.ebay.com/itm/174977901251
<https://www.ebay.com/itm/174977901251>
>
> 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" .
7 Jan
7 Jan
6:25 a.m.
According to www.rcaselectron.com RCA made 9, 256, 1024 and 4096 bit
versions of the Selectron tube.
I don't know if any of them other than the 256 bit made it into production.
4096 Bit Selectron Pics http://www.rcaselectron.com/sel4096.html (4 by 1024)
1024 Bit Selectron Pics http://www.rcaselectron.com/sel1024.html (2 by 512)
256 Bit Selectron Pics http://www.rcaselectron.com/sel256.html (2 by 128)
9 Bit Selectron Pics http://www.rcaselectron.com/sel9.html
On 1/6/2022 8:10 PM, Eric Smith wrote:
On Thu, Jan 6, 2022, 08:45 Mike Katz via cctalk
<cctalk at classiccmp.org> wrote:
There was also a 1K by 4 version of this tube.
I've never seen any info on a 1K*4 Selectron, but they weren't even
able to make the 4K*1 work, and the only production tubes were 256*1.
6 Jan
6 Jan
1:06 a.m.
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 classiccmp.org>
To: "'General Discussion: On-Topic Posts'" <cctech at
classiccmp.org>
Sent: Wednesday, 5 Jan, 2022 At 17:35
Subject: Memory Tech you don't see very often
Selectron Vacuum Tube: https://www.ebay.com/itm/174977901251
<https://www.ebay.com/itm/174977901251>
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" .
7:14 a.m.
On Jan 6, 2022, at 4:06 AM, Brent Hilpert via cctalk
<cctalk at classiccmp.org> wrote:
On 2022-Jan-06, at 12:19 AM, Joshua Rice via cctech wrote:
Yes, for example in van Wijngaarden's 1948 course text "principles of electronic
calculating machines", the Selectron is explained in detail (as a 4k bit device,
which apparently was the original hope). It also mentions something like a Williams tube
(not by that name, so perhaps it's not exactly that). The only other idea for a
random-access RAM that it mentions is a rather vague notion that a crossbar of gas
discharge elements could be used. That was later (1960) used as a display device, the
famous plasma panel display invented by Don Bitzer et al.; not clear if it was ever
actually used as a memory device. Core memory does not appear in that 1948 document,
that's a later invention but indeed the one that ended up successful in practice.
paul
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. 
9:41 a.m.
Perhaps even rarer were the EBAM tubes that CDC worked with during the
1970s. I recall seeing a 6' rack of a complete assembly sitting in a
hallway at ADL around 1974. If CDC followed the dictates of management
then, the unit was probably utterly demolsihed before being sold as
scrap metal.
--Chuck
9:46 a.m.
Prototypes don't count.
--
Will
On Thu, Jan 6, 2022 at 12:41 PM Chuck Guzis via cctech
<cctech at classiccmp.org> wrote:
Perhaps even rarer were the EBAM tubes that CDC worked with during the
1970s. I recall seeing a 6' rack of a complete assembly sitting in a
hallway at ADL around 1974. If CDC followed the dictates of management
then, the unit was probably utterly demolsihed before being sold as
scrap metal.
--Chuck
6:15 p.m.
On Thu, Jan 6, 2022, 01:20 Joshua Rice via cctech <cctech at classiccmp.org>
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.
The rarity wasn't that only one _model_ of computer used it. Only one
_unit_ used it. It used 80 tubes at a cost of around $500 each, in
mid-20th-century dollars.
Given that they'd have needed some spares and replacements, the production
run would have been more than 80 pieces, but I'd think it unlikely that
more than 250 production units were ever made.
If someone wants one and is able to purchase it for $10,000, I think they
are very lucky.
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