Electromechanical relay units for the ETL Mark II

Electromechanical relay units for the ETL Mark II

Title page of the first book on an electromechanical computer made in Japan.
The first Japanese book published in English concerning an electromechanical digital computer built in Japan. Origins of Cyberspace 637
Detail map of 10, 6-chōme, Roppongi, Minato City, Tōkyō-to, Japan Overview map of 10, 6-chōme, Roppongi, Minato City, Tōkyō-to, Japan

A: 10, 6-chōme, Roppongi, Minato City, Tōkyō-to, Japan

The ETL Mark II, the First Full-Scale Programmable Japanese Electromechanical Computer, is Produced

11/1955
ETL Mark II operating console

ETL Mark II operating console

ETL Mark II, the first full-scale programmable computer built in Japan, was produced by the Electrotechnical Laboratory in Roppongi, Tokyo. It incorporated 22,253 relays, and did not store a program. The system was completed in November 1955, and was used for calculations in and outside the Electrotechnical Laboratory for about 10 years.

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