A computer that refuses to die

The “life time” of technology has been reduced – smartphones can be changed at least every year. But there is still equipment that has been working for decades and is likely to work for many more years. One such system is Japanese FACOM 128Bput into operation in 1958.


A photo – Daderot – PD / In the photo: FACOM 128B follower – FACOM 201A

How FACOM appeared

In the early 1950s, computers were built on electronic tubes – they were used in the first commercial computer Ibm model 701. These items were difficult to maintain and often failed. Therefore, some companies chose a different path and began to develop electromechanical computers based on relays and switches. Among them was the Japanese Fujitsu Corporation. She planned to compete with the American “blue giant“.

In 1954, Toshio Ikeda, head of computer technology at Fujitsu, initiated the development of a new computing system. In it the role of logical elements were playing switching relays used in telephone exchanges. The company’s engineers used 4,500 of these relays and assembled a computer from them. FACOM 100. Two years later, an improved version of the system saw the light – FACOM 128A, and in 1959 – FACOM 128B.

Computer features

Fujitsu’s performance was significantly lower than that of electronic lamp machines. For example, IBM 701 was spending the addition operation is about 60 milliseconds. FACOM 128B similar task performed in 100-200 milliseconds. It took up to 350 milliseconds to multiply two numbers, and much more for complex logarithmic operations.

The lack of performance FACOM 128B made up for reliability and ease of maintenance. All arithmetic operations were performed in the decimal system, and the numbers were encoded with a binary-five-digit code (bi-quinary) To indicate the number in memory, seven bits were allocated – 0 5 and 0 1 2 3 4, which allowed you to encode any digit from zero to nine, “lighting” two bits in the sequence.

Such an approach greatly simplified search for stuck relays. If the number of active bits is not equal to two, then it became obvious that a failure occurred. Finding a faulty component after that was also easy.

The FACOM 128B computer was used until the 1970s. With its help, they designed special lenses for cameras and NAMC YS-11 – The first passenger airliner built by the Japanese after the end of World War II.

How’s FACOM doing today?

FACOM 128B is no longer used for any serious calculations and calculations. The car turned into a full-featured museum exhibit installed in the “hall of fame” of the Fujitsu Numazu Plant in Numazu.

The computer’s performance is monitored by a single engineer, Tadao Hamada. By his according to, he will “remain on the post” for the rest of his life, as he wants to preserve Japan’s technological heritage for posterity. He notes that repairing the system does not require significant effort. The FACOM 128B is so reliable that it only needs to be replaced with one relay per year, despite daily demo runs.

Most likely, the computer will work for many more years, even after the departure of Tadao Hamada. Confidence is inspired by the fact that last year the National Museum of Nature and Science of Tokyo turned on FACOM 128B is a list of technologies of historic importance.

Other “centenarians”

Another computer that continues to work since the 50s of the last century installed in the American company Sparkler Filters (supplies filtering devices). This car – Ibm 402, which is an electromechanical calculator that reads information from 80-column punch cards. It is believed that this is the last fully functioning IBM 402 on the planet.

Unlike the FACOM 128B, which is an exhibit, the machine is used for bookkeeping and financial reporting. Corresponding computer programs are stored in the form of patch panels, on which the technological sockets are connected by wires that determine the operation algorithm.


A photo – Simon claessen – CC BY-SA

So far, the company does not plan to switch to modern computing systems and refuse a unique computer. But there is a possibility that in the future, the IBM 402 will go to the Museum of Computer History. Its representatives in the past are already contacted Sparkler Filters, but then negotiations did not lead to anything.

Another example of a long-lived computer is DEC MicroVAX 3100which since 1987 use at Hecla Mining, a mining company for silver and other precious metals. The computer is installed at a station in Alaska, where it estimates ore parameters and prints labels for samples. By the way, the same old printer is responsible for the latter. Interestingly, seven years ago, one of the Hecla Mining engineers in a thematic post on Reddit noted that “he does not need to play a series Fallout, since it already works on a “post-apocalyptic” PC. There is some truth in this – monitor with orange characters definitely adds surroundings.


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What else is on our blog on Habré:

  • Most supercomputers are running Linux – discuss the situation
  • A Brief History of Fidonet, a Project That Doesn’t Care About Winning Over the Internet

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