A Look Back At The USSR Computer Industry

According to [Asianometry], in 1986 the Soviet Union had about 10,000 computers. At the same time, the United States had 1.3 million! The USSR was hardly a backward country — they’d launched Sputnik and made many advances in science and mathematics. Why didn’t they have more computers? The story is interesting and you can see it in the video below.

Apparently when news of ENIAC reached the USSR, many dismissed it as fanciful propaganda. However, there were some who thought computing would be the future. Sergey Lebedev in Ukraine built a “small” machine around 1951. Small, of course, is relative since the machine had 6,000 tubes in it. It performed 250,000 calculations for artillery tables in about 2 and half hours.

The success of this computer led to two teams being asked to build two different machines. Although one of the machines was less capable, the better machine needed a part they could only get from the other team which they withheld, forcing them to use outdated — even then — mercury delay lines for storage.

The more sophisticated machine, the BESM-1, didn’t perform well thanks to this substitution and so the competitor, STRELA, was selected. However, it broke down frequently and was unable to handle certain computations. Finally, the BESM-1 was completed and was the fastest computer in Europe for several years starting in 1955.

By 1959, the Soviets produced $59 million worth of computer parts compared to the US’s output of around $1 billion.  There are many reasons for the limited supply and limited demand that you’ll hear about in the video. In particular, there was little commercial demand for computers in the Soviet Union. Nearly all the computer usage was in the military and academia.

Eventually, the Russians wound up buying and copying the IBM 360. Not all of the engineers thought this was a good idea, but it did have the advantage of allowing for existing software to run. The US government tried to forbid IBM from exporting key items, so ICL — a UK company — offered up their IBM 360-compatible system.

The Soviets have been known to borrow tech before. Not that the west didn’t do some borrowing, too, at least temporarily.

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A vacuum tube computer next to a part of its schematic

This Colossal Vacuum Tube Computer Plays A Mean Game Of Pong

It doesn’t happen often that we report on new vacuum tube based computer designs. Today however, we’re pleased to introduce to you the Fast Reliable Electronic Digital Dot Computer, or Fred.Computer for short. It’s the brainchild of [Mike] who also brought us ENA, which we featured earlier.

Fred is a new design that reuses the parts that made up ENA. It has an 8-bit CPU, 16 bytes of RAM, 256 bytes of NVRAM, and runs at a clock speed of 11.3 kHz. With its 560 tubes drawing a total supply current of about 200 A it also provides a fair bit of heating to [Mike]’s study. The main logic is implemented through NOR gates, built from 6N3P dual-triode tubes sourced from Eastern Europe. These NOR gates are combined into more complex structures like latches, registers and even a complete ALU. A total of sixteen machine code instructions can be used to write programs; clever design allows Fred to perform 16, 32 or even 64-bit calculations with its 8-bit ALU.

A PCB with many reed relays
Need some RAM? There’s sixteen bytes right here.

An interesting addition is a new RAM design based on reed relays. [Mike] realised that relays are actually very similar to digital transmission gates and can therefore be used to make a simple static RAM cell. If you thought relays were too slow for RAM cells, think again: these reed relays can toggle at a mind-boggling 700 Hz, making them more than fast enough for Fred.

The main I/O device is a console that contains several pushbuttons as well as a 12 x 8 LED display. All of this makes Fred a fully-functional general-purpose computer that’s even capable of playing Pong (video, embedded below). [Mike]’s website is full of interesting detail on all aspects of vacuum tube computer design, and makes delightful reading for anyone tempted by the idea of building their own.

Can’t get enough of vacuum tube computers? Have a look at this 1-bit MC14500 implementation, marvel at this modern interpretation of an adding machine, or find out how IBM designed its logic in the 1950s.

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The insides of a vacuum tube computer

1950s Vacuum Tube Computer Replica Communicates Through USB

When we talk about a “computer” today, we generally picture an electronic machine that can perform various kinds of mathematical operations, manage its program flow, move data from one place to another, and string all these functions together to perform some useful task. But once upon a time there were machines that could perform only a subset of these functions; these might be classified somewhere between computers and calculators.

One such machine was the Elektronensaldierer ES 24, built in 1955 by German computer pioneer Heinz Nixdorf. Its name translates as “electronic balancer”, with “balance” in the accounting sense meaning the difference of assets and liabilities. Designed to interface with a punch card machine from French manufacturer Bull, it contained several hundred vacuum tubes and could be used to add and subtract numbers stored on those punch cards.

[Henry Westphal] decided to make a modern copy of the ES 24 (translated), based on Nixdorf’s original schematics, for display in the HNF computer museum in Paderborn. The result is a huge display containing 204 tubes as well as a massive power supply. Like the 1955 original it can add incoming numbers and output the result as a twelve-digit decimal number. To make its inner workings visible, [Henry] also added a status light to each tube, showing whether it is storing a “0” or a “1”. This makes for a beautiful Blinkenlights display that shows the bits moving through the machine’s inner circuits.

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Single Bit Computer From Vacuum Tubes

Culminating a year-long project, [Usagi Electric] aka [David] has just wrapped up his single-bit vacuum tube computer. It is based on the Motorola MC14500 1-bit industrial controller, but since [David] changed the basic logic unit into an arithmetic-logic unit, he’s dubbing it the UE14500. Built on a wooden panel about 2.5 x 3 rabbit lengths excluding power supply. [David] admits he has cheated a little bit, in that he’s using two silicon diodes instead of a 6AL5 dual diode tube in his universal NOR gate on which the computer is based — but in his defense he notes that plenty of vacuum tube computers of the era used silicon diodes.

The tube he uses in the NOR gates is the 6AU6 miniature pentode, which he selected because of its availability, price, and suitability for low voltage. [David] runs this computer with two power supplies of +24 and -12 VDC, rather than the hundreds of volts typically used in vacuum tube designs. The modules are constructed on single-sided copper-clad PCB panels etched using a milling machine. The video below the break wraps up the 22-part series, where he fixes a few power supply issues and builds a remote front panel for I/O, and gives a demo of the computer in operation. Alas, this only completes one fourth of the project, as there are three more building blocks to build before the whole system is complete — Program Control (magnetic tape), RAM Memory bank, and a serial input/output module. We look forward to seeing the whole system up and running in the future.

We just wrote about the MC14500 a few days ago, and we’ve also covered [David]’s vacuum tube implementation of a 555 timer among other of his vacuum tube projects, several of which are featured on his Hackaday.io page.

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