[vcf-midatlantic] vacuum tube computers, was Re: Museum Report 2017-11-26 November 26, 2017

Dave McGuire mcguire at neurotica.com
Sun Nov 26 20:50:30 EST 2017

On 11/26/2017 04:54 PM, Jeffrey Brace via vcf-midatlantic wrote:
> The parents love the explanation of the progression of technology. I need
> to learn more about how vacuum tube computers work to give them a
> comparison.

  It's important to realize that there's really no difference.  Vacuum
tubes are analogous to FETs (field-effect transistors) and are simply
the active switching element of tube-based digital computers, where
transistors are the active switching element of solid-state computers.
The logic...the instruction set, buses, etc...can be identical.  The
only real reason they're not is because computer architecture has grown
up alongside, but largely independent of, electronics technology.

  Now if you're talking about tube-based analog computers, that's a
different animal...and the same point applies there.  Analog computers
are (mostly) composed of op-amps, and those op-amps can be built with
tubes or transistors. (with or without multiple transistors being
"integrated" into one "circuit", i.e. using integrated circuits)  Again,
the architecture is (or at least can be) the same.

  The takeaway here is the importance of understanding the difference
between architectures and implementations.


Dave McGuire, AK4HZ
New Kensington, PA

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