Questions tagged [vacuum-tube]

Vacuum-tube computing, i.e. the use of vacuum tubes (also known as valves) as logic devices. Questions about cathode ray tubes should use the [crt-monitor] tag instead.

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5
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1answer
306 views

What's the minimum number of tubes per bit required to store a register?

What is the minimum number of tubes per bit required to store a CPU register in a vacuum-tube computer? In particular, have any real vacuum-tube computers ever successfully stored more than 1 bit of a ...
13
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4answers
602 views

Did vacuum-tube computers ever reach a physical limit to their speed?

Grace Hopper famously used 30 cm pieces of wire as a teaching aid to show how far signals can travel in one nanosecond. Indeed, the speed of light has become a limitation for many computers. The ...
34
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8answers
6k views

Why were relays prevalent in early 1940s computers when vacuum tubes were also available?

Many of of the computers built in the 1940s used relays for logic (see here and here): Bell Labs Model I, 1940 Bletchley Park Bombe, 1940 Zuse Z2, 1940 Zuse Z3, 1941 Bell Labs Model II, 1943 Bell ...
7
votes
4answers
659 views

Have there been any studies comparing the reliability of relay versus vacuum tube computers?

Computers of the first half of the 20th century generally used relays or vacuum tubes as their logic elements. Each of these components has there own methods of failure, but relays and tubes have a ...
5
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2answers
971 views

Were any vacuum tube computers built with wire wrap?

I'm trying to gain some understanding of how early computers were built; as discussed in What accounted for the cost of ENIAC? the cost of first-generation computers was not necessarily mostly about ...
4
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2answers
269 views

How many 6SN7 tubes did it take to store a bit?

One of the most important components of a computer is a circuit called a flip-flop, which has two stable states (that it can flip-flop between, hence the name); it is used for temporary storage of a ...
4
votes
1answer
301 views

IBM 650 - how many logic gates?

How many logic gates did the IBM 650 have? I'm used to measuring the complexity of a CPU by transistor count, but the 650 was a vacuum tube machine; the number of tubes would also be an interesting ...
12
votes
7answers
2k views

Can I build a working(ish) vacuum tube byte?

This is a somewhat odd question. I teach a course on media history, and spend some time talking about digital data towards the end. I am interested in building a device to illustrate some basic ideas ...
9
votes
1answer
566 views

Where are the Colossus schematics?

The Colossus series of electronic computers, considered by some to be the first fully electronic (as opposed to electromechanical) computer in the world, was originally a British state secret. This ...