Columbia University Computing History   
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Simon - The Smallest Mechanical Brain in Existence!

Edmund Berkeley was a World War II Navy veteran, anti-nuclear peace activist, and an early computer scientist[1,2]. He was co-founder of the Association of Computing Machinery (ACM) at Columbia University's Havemeyer Hall September 15, 1947[3,4]. He wrote the first popular book about computers, Giant Brains, in 1949[5]. As described in the 1950 Columbia University press release transcribed just below the images, he designed and built "Simon", the "world's smallest mechanical brain" at Columbia University with the help of two WWII-veteran Columbia Engineering graduate students and a machinist from Massachusetts [6,7,8,9].

Click each image to enlarge...
Edmund Berkeley explains Simon's punched paper tape
Radio Electronics Magazine
Radio Electronics Magazine, Oct 1950

Fact Sheet on "Simon"
Public Information Office
Columbia University May 18, 1950

What is "Simon"? A very simple model, mechanical brain — the smallest complete mechanical brain in existence. The machine was conceived by Edmund C. Berkeley, president of E.C. Berkeley and Associates actuarial consultants (of 60 State Street, Boston, and 36 West 11th Street, New York). Mr. Berkeley described the machine, before he had it built, in his book, "Giant Brains, or Machines That Think," which was published last November. In the book, he wrote:

"We shall now consider how we can design a very simple machine that will think.. Let us call it Simon, because of its predecessor, Simple Simon... Simon is so simple and so small in fact that it could be built to fill up less space than a grocery-store box; about four cubic feet....It may seem that a simple model of a mechanical brain like Simon is of no great practical use. On the contrary, Simon has the same use in instruction as a set of simple chemical experiments has: to stimulate thinking and understanding, and to produce training and skill. A training course on mechanical brains could very well include the construction of a simple model mechanical brain, as an exercise.

Who built "Simon"? The machine represents the combined efforts of a skilled mechanic, William A. Porter, of West Medford, Mass., and two Columbia University graduate students of electrical engineering, Robert A. Jensen (of 76-19 175th Street Flushing, L.I., N.Y.) and Andrew Vall (of 4237 Judge Street, Elmhurst, L.I.,N.Y.). Porter did the basic construction, while Jensen and Vall took the machine when it was still not in working order and engineered it so that it functioned. Specifically, they

designed a switching system that made possible
the follow-through of a given problem;

set up an automatic synchronizing system;

installed a system for indicated errors due
to loss of synchronization;

re-designed completely the power supply of the

In their own words, the two students simply put to work their knowledge of electrical engineering, after mastering the mass of intricate detail with which they were presented last March, when Mr. Berkeley brought "Simon" to Columbia.

Capsule biographies: Vall, 23, received his bachelor's degree from Columbia's school of Engineering in 1949, and is working for his master's degree in electrical engineering. In June, he will join Bell Telephone Laboratories to do electronic development work. He is an Army veteran. Jensen, 25, holds a bachelor's degree from City College (1949) and is now working for his master s degree. He hopes to do development work in the computer or switching field. He is a veteran of three-and-a-half years with the Army Air Forces.

What operations does "Simon" perform? Addition, negation, greater than, and selection.

What did "Simon" Cost? About $600. The time and effort of the two Columbia students was contributed.

What makes "Simon" unique? According to Mr. Berkeley, the machine has established at least half a dozen world's records:

What is the machine's future? Mr. Berkeley's answer follows:

"Simon has two futures. In the first place Simon can grow. With another chassis and some wiring and engineering, the machine will be able to compute decimally, Perhaps in six months more, we may be able to have it working on real problems. In the second place, Simon may start a fad of building baby mechanical brains, similar to the hobby of building crystal radio sets that swept the country in the 1920's."

* * *

  1. Edmund Berkeley, Wikipedia, accessed 28 March 2021.
  2. Edmund C. Berkeley, IEEE Computer Society Computer Pioneers.
  3. Association for Computing Machinery, Wikipedia, accessed 11 April 2021.
  4. Minutes of the ACM's first meeting at Columbia U, 15 September 1947.
  5. Edmund C. Berkeley, Giant Brains or Machines That Think, Wiley (1949).
  6. Edmund Berkeley and Robert A. Jensen, World's Smallest Electronic Brain, Radio Electronics, October 1950 (cover story).
  7. Simple Simon, Scientific American, November 1950 (cover story).
  8. Simon Electronic Brain — Complete History of the Simon Computer,, accessed 28 March 2021.
  9. Simon the First Personal Computer, Aneddotica magazine, 22 March 2015.

Translations of this page courtesy of...

Language Link Date Translator Organization
Belarusian Беларуская 2023/08/22 Vladyslav Byshuk | Владислав Бишук
Finnish Suomi 2023/08/31 Kerstin Schmidt
French Français 2023/08/25 Kerstin Schmidt
German Deutsch 2023/08/25 Kerstin Schmidt
Italian Italiano 2023/08/31 Kerstin Schmidt
Polish Polski 2023/08/25 Kerstin Schmidt
Norwegian Norsk Bokmål 2023/03/04 Stian Skjelbred
Russian Русский 2023/08/22 Vladyslav Byshuk | Владислав Бишук
Spanish Español 2023/08/31 Kerstin Schmidt
Ukrainian Українська 2023/08/22 Vladyslav Byshuk | Владислав Бишук

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Columbia University Computing History Frank da Cruz / This page created: January 2001 Last update: 8 September 2023