Innovation in the Transition Period Taught by Pre-PC Relay Computers - Memories of the Dawn of the Personal Computer

The clicking heartbeat that breaks the silence

When a program does not work as intended, we naturally say that a "bug has appeared."
Did you know that this everyday term in the IT industry originated from a "real moth" that was once caught in the gaps of a computer?

In 1940s America, when the massive "Mark II" computer installed at Harvard University began to malfunction, technicians searched for the cause and found a bug literally stuck inside.
They plucked the moth out with tweezers, taped it into the logbook, and wrote that a "bug had been discovered."

Why did an insect get into such a place?
The cutting-edge computers of that time were neither quiet nor compact like today's smartphones or PCs. They were monsters that filled the room with a tremendous physical sound, like a giant weaving factory or a room full of typewriters all clattering at once.

The source of this sound was the "relay" (electromagnetic relay), a switch that physically moved metal contacts using electromagnets.
There was a unique fervor on the eve of the digital age, where, despite using the power of electricity, the inner workings were still mechanical.

From gears to electricity: The freedom gained by 0 and 1

Before the advent of relay computers, the essence of calculation was bound by the "shape of matter." Whether it was an abacus, a mechanical calculator on a desk, or the advanced analog computers of the time, what represented numerical values was always a continuous physical quantity, such as the rotation angle of a gear or the position of a lever.

However, with the introduction of the relay component, the concept of calculation changed completely. A relay can only do one of two things: allow current to flow to "turn on" the switch, or stop the current to "turn it off."

This extremely simple binary mechanism synchronized perfectly with the "binary system," which is the foundation of modern computers. In other words, it was the birth of digital logic circuits where ON is 1 and OFF is 0.

The historical significance of this shift cannot be overstated. Because it was freed from the physical constraints of gears, calculation was elevated to invisible information known as "electrical signals."
Without having to modify the structure of the main unit, one could automatically perform completely different calculations simply by loading punched paper tape (a program). The software philosophy held by modern PCs was already perfected in those rooms filled with clicking relays.

A drama of the transition period woven by geniuses from Japan and Germany

During this era, there were brilliant minds all over the world trying to get ahead of their time.

The first person we should look at is Konrad Zuse in Germany during World War II.
Without receiving generous financial support from the state, he attempted to automate aircraft design calculations in an isolated environment.
With supplies critically low, he turned his attention to relays from discarded telephone exchanges. By combining these with off-the-shelf parts at home, he completed the "Zuse Z3" in 1941, which would go down in history as the world's first programmable, fully automatic digital computer.
It is thrilling that at almost the same time the United States was building the massive "Harvard Mark I" with all its might, the same idea was blossoming on one man's writing desk.

Meanwhile, in post-war Japan, a drama no less compelling was unfolding. It was the challenge of developing a domestic computer, led by engineers like Kenichi Goto of Fujitsu.

At that time in Japan, the quality of cutting-edge "vacuum tubes (electronic type)" was extremely poor, and they would burn out as soon as electricity was applied. While looking up at the American vacuum tube computers that were achieving remarkable speeds, the Fujitsu team made a pragmatic decision: they would build a computer using relays for telephone exchanges, which had well-established reliability within the country.

Thus, the "FACOM 128A" was born in 1956.
Naturally, a relay-based system where metal moves physically is overwhelmingly slower than a vacuum tube system that operates at the speed of electrons. However, Fujitsu's engineers incorporated a unique mechanism called a "self-checking circuit." If dust were to get caught in a relay and cause a calculation error, the hardware itself would detect it and instantly rotate the relay in reverse to redo the calculation.

"The calculation speed is slow, but it never makes a mistake."

This machine, equipped with astonishing reliability, supported Japan's aircraft design and lens calculations at the time, driving Japanese manufacturing from behind the scenes. Even if it was not technically cutting-edge, they maximized its practicality through ingenuity in design philosophy.

The lesson of those that lost to vacuum tubes, yet became the blueprints for the modern era

The era of relay-based systems was surprisingly short-lived. Although they reached their peak in the 1940s, by the late 1950s, they were swallowed by the wave of overwhelmingly faster 'electronic' systems using vacuum tubes and transistors, and were forced to relinquish their leading role.

From the cold perspective of business history or mere competition in specifications, relay systems might be seen as nothing more than obsolete relics. However, it may be a mistake to dismiss them so easily.

Many modern companies are eager to introduce 'the latest AI' or 'cutting-edge cloud systems' under the grand banner of DX. However, there are not a few cases where, despite investing huge sums to install the latest systems, they become useless because the organization's management style or business processes (philosophy) remain outdated.

What the era of relay systems teaches us is the exact opposite approach.
While using the worn-out technology (relays) at hand, they completely anticipated and built the 'concepts (software design philosophy)' of the next generation. Because they had thoroughly verified the framework of the architecture using old technology, the digital revolution was able to proceed at an explosive speed when the true hardware, such as vacuum tubes and semiconductors, finally arrived.

'Rather than jumping on immature cutting-edge technology, use mature technology to complete the philosophy of a new era first'

The relay computers that clicked as they operated were not merely stepping stones to electronics. They were, in themselves, a sophisticated strategy of innovation for surviving a period of intense technological transition.

[Casual Memo] Historical Significance and Mechanisms of Relay Computers

The era of 'electromechanical computers (relay-based)' is an important page in history, positioned exactly in the 'transition from analog to digital,' leading from pure mechanical computers using gears to later electronic ones (vacuum tubes and transistors).

1. Historical Background and Technical Mechanism (What were they, anyway?)

This was an era that attempted to overcome the limitations of pure 'gears' with 'electricity.' They reached their peak from the late 1930s to the 1940s.

・Relays (electromagnetic relays) were the main players
Components called 'relays' were used to switch the on/off state of circuits using electrical signals. When current flows, an electromagnet is activated, and a physical contact moves with a 'click' to switch the circuit.

・The 'clicking' operating sound
Because thousands or tens of thousands of relays moved simultaneously, the computer room during operation was filled with a tremendous 'clicking sound,' as if giant looms or typewriters were all working at once.

・Establishment of the binary system (digital)
From the analog/mechanical era, where numerical values were represented by the 'rotation angle (decimal system, etc.)' of physical gears, the foundation of modern digital computers, which process using '0 and 1 (binary system)' via switch ON/OFF, was clearly defined here.

2. Representative Computers That Moved History (What kind of machines were there?)

During this era, original relay computers were born in the United States, Germany, and Japan.

・Zuse Z3 (Germany / Konrad Zuse / 1941)
It is said to be the world's first 'programmable, fully automatic digital computer.' It used about 2,000 relays and adopted the binary system.

・Harvard Mark I (USA / Howard Aiken & IBM / 1944)
A massive electromechanical computer measuring approximately 15 meters in length and weighing about 5 tons. It was used for tasks such as ballistic calculations for the U.S. Navy.

・FACOM 128A (Japan / Fujitsu / 1956)
A pioneer of Japanese computers. It featured advanced self-checking functions and boasted such high reliability that it was said to "never make a calculation error." Surprisingly, it is still preserved in working condition today.

3. Differences from mechanical and electronic (vacuum tube) types (What were the advantages and limitations?)

By comparing it with the eras before and after, the position of the relay type becomes clear.

・Differences from mechanical types (speed and automation)
It broke through the limitations of humans turning handles or coordinating complex gears. "Automated calculation by program" using electrical signals became possible, and calculation speed improved dramatically.

・Differences from vacuum tube types (speed and reliability)
Compared to the vacuum tube (electronic) types like the "ENIAC" that appeared shortly after, the relay type, which physically moved metal, was overwhelmingly slower (relays could switch dozens of times per second, while vacuum tubes could switch tens of thousands of times or more per second). However, they did not burn out easily like vacuum tubes, and for the technology of that time, it was considered that "relay types were overwhelmingly more durable and reliable."

4. Connection to modern IT and business (How is it utilized today?)

It is not just a relic of the past; the "blueprint" for modern computers was completed here.

・The origin of the word "Bug"
A moth (a real insect) got stuck in a relay computer called the Mark II and caused a malfunction. An engineer taped it into a logbook with the note "bug found," which is considered one of the origins of the term "bug" used for modern system glitches.

・The birth of programming philosophy
The method of reading instructions via punched paper tape became established, and the concept identical to modern PCs—"performing different calculations by swapping software (instruction tapes) without changing the hardware (the computer itself)"—was established.

Related Articles

・History and Technical Evolution of Calculators and Computers

Book Introduction

・Our PC 30-Year History: Nippon PC Chronicle Kindle Edition
Edited by SE Editorial Department
Shoeisha (2012/12/20)
A Japanese PC history textbook that looks back with photos. It explains the major changes in PCs over more than 30 years in two parts, using many photos and touching on social conditions to make the flow of time easy to understand. Part 1 is dedicated to explaining topics by era, incorporating "testimonies (turning points)" from developers and people involved at the time to reveal behind-the-scenes development stories. Part 2 summarizes PC architecture and other topics by theme.
(※ Book descriptions, etc., are generally based on the descriptions on the linked site (Amazon). Please refer to the link for detailed content.)

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