Parametron: 50s Japanese computer that uses neither transistors nor vacuum tubes

Magnetic devices have the nice property that there's no wear-out mechanism. They're just coils and magnetic materials. They just keep going, for many decades. The Bell System loved nonlinear magnetic devices. There were lots of them, usually potted inside little grey boxes. Here's one of many on eBay.[1]

[1] https://www.ebay.com/itm/318704409860

Expanding the question because it's the same answer for all of them: The relatively steady exponential progress of transistors murdered all the competition. Nobody had any time to think about anything else when 18 months from now the transistors would be twice as fast and cheaper at the same time. It also meant a technology had to pretty much come out of the gate already better than transistors which had been through numerous doublings. It doesn't matter if you produced something that could hypothetically double every three months for ten years if it started out a hundred times slower and a thousand times more expensive than the transistors at release day. It couldn't survive long enough in the market to get funded long enough to develop that far.

It's only now that you can really get going on some alternative... and it still kind of sucks that even so you need to produce something out of the lab that beats transistors on some relevant metric right now if you want to get anywhere. Trillions of dollars of investment into transistors is hard for any tech to overcome, even if hypothetically in 10 years it could spank transistors somehow.

After WWII, the technology of magnetic amplifiers was one of many technologies that USA took from Germany and provided to US companies (like also the Soviet Union did with their part of Germany, but while USA took the technical documentation and samples of the products, the Soviet Union moved entire factories to Russia, piece by piece).

But they substantially predate World War II and were once widely deployed and widely understood. The technology goes back to at least the late 19th century. It was used in many of the places where we'd use an amplifier today, like to run signals in a factory where hydraulics are not practical.

They can be quite fast - if the AC supply is well into the 10s of KHz they can reproduce audio range frequencies.

Some of the first electronic radio transmitters were based on the magnetic amplifier. The radio pioneer Reginald Fessenden developed a system using his Alexanderson alternator (a super-high-speed AC generator) which produced high power (many kilowatts) of AC at the target carrier frequency of around 30 kHz. He then fed the output of that, through a large magnetic amplifier, governing the kilowatts of generator output, with a small control current from a switch or microphone -- amplitude modulation. That was c. 1916.

The quick summary is that magnetic amplifiers started in the US in 1901, but Germany came up with much better magnetic alloys during World War II. This led to a post-war boom in mag amps, which were used in industrial control, aerospace, and computers such as the Univac Solid State. These magnetic materials also led to core memory. Transistors mostly killed off mag amps, although PC power supplies used them into the 1990s.

Even compared to contemporary vacuum tubes they were slower. Contemporary bleeding edge vacuum tube computers could reach Mhz frequencies. Parametrons were 10-15kHz.

The supposed power benefits depended on state. At idle they were significantly more efficient but the more work they did and the faster you tried to run them the exponentially more electricity they required (and heat they generated).

Lastly because the early ones were lower frequency they required physically larger inductors. Contemporary vacuum tube computers took up similar amounts of space due to cooling constraints but parametrons were bulky in ways you couldn't fix.

Parametrons were a dead-end technology almost from the get-go due to physical scaling limits. Even the earliest use of discrete transistors blew them out of the water beyond any hope that some magical physical scaling would rescue them.

Abandoned technologies are usually abandoned for very good reasons not just because they happened to lose the race or get backed by the wrong companies. No amount of investment was ever going to help parametrons catch up with transistors - just as no amount of investment was going to help vacuum tubes catch up either.

The operating principle was different than that of the parametron, but the end effect was about the same. It used highly non-linear magnetic cores, which could not be switched by one or a few current pulses coming through wires passing through them, but enough pulses would switch the core.

This kind of logic gate, where many inputs are added and the gate switches when their sum exceeds a certain threshold, can be implemented with a wide variety of devices.

The so-called resistor-transistor logic, which was used in some early computers and there were even integrated circuits based on it, works in the same way. When enough of the input resistors are connected to high voltages, the voltage raises enough to switch on the transistor that follows the resistor network.

The logic gates with magnetic cores of Elliott 803 worked in the same way, even if they summed the magnetic fields of currents through wires and the switching threshold was determined by a non-linear magnetic core.

The neurons also use a logic of the same type, i.e. they switch on when enough synapses are excited, even if there are a lot of extra complications, as some synapses are inhibitory and the threshold for switching on is not a constant, but it is variable, depending on the history of the previous excitations.

Besides the inventor of parametron, there is also Kazushige Goto, who became famous after writing in 2002 the library GotoBLAS, which was for some years the fastest library for linear algebra and which inspired all later such libraries. He later worked at Microsoft, then at Intel.

What is funny is that searching right now "Kazushige Goto" in Bing, it immediately returned a confident AI answer that "Kazushige Goto was a Japanese scientist who invented the parametron in 1954 while he was a ...".

I pity those who believe any of the AI answers that most search engines force now upon their users.

I wonder if there is any relationship between the 2 Goto, but it is unlikely, because Goto is not rare among the Japanese family names.