Simon (computer)

Simon was the name given to the first "personal computer" [ [http://www.blinkenlights.com/pc.shtml What was the first personal computer?] at "Blinkenlights Archaeological Institute". Accessed: March 15, 2008.] of history, a project developed by Edmund Berkeley and presented in a thirteen articles series issued in "Radio-Electronics" magazine, from October 1950. Although there were far more advanced machines at the time of its construction, the Simon represented the first experience of building an automatic simple digital computer, for educational purposes. In 1950, it was sold for US$600.

History

The "Simon project" arose as a result of the Berkeley's book "Giant Brains, or Machines That Think", published in November 1949. There, the author said:

:cquote|"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."

In November 1950, Berkeley wrote an article entitled "Simple Simon" for "Scientific American" magazine BERKELEY, E.C. (1950). "Simple Simon" in Scientific American, No. 183, November 1950, pp. 40-43] , which was a description of the digital computing principles for the general public. Despite Simon's extreme lack of resources (it was able to represent only the numbers 0, 1, 2 and 3), Berkeley stated on page 40 that the machine "possessed the two unique properties that define any true mechanical brain: it can transfer information automatically from any one of its "registers" to any other, and it can perform reasoning operations of indefinite length". Berkeley concluded his article anticipating the future:

:cquote|"One day we may even have small computers in our homes, drawing energy from electric power lines like refrigerators or radios ... They may recall facts for us that we would have trouble remembering. They may calculate accounts and income taxes. Schoolboys with homework may seek their help. They may even run through and list combinations of possibilities that we need to consider in making important decisions. We may find the future full of mechanical brains working about us".

Technical specifications

The Simon's architecture was based on relays. The programs were run from a standard paper tape with five rows of holes for data. The registers and ALU could store only 2 bit. The data entry was made through the punched paper or by five keys on the front panel of the machine. The output was provided by five lamps.

Programming

The punched tape served not only for data entry, but also as a memory for the machine. The instructions were carried out in sequence, as they were read from the tape. The machine was able to perform four operations: addition, negation, greater than and selection.

Notes

External links

* [http://www.blinkenlights.com/classiccmp/berkeley/simonfaq.html Simon's FAQ]
* [http://www.cs.ubc.ca/~hilpert/e/simon/index.html Edmund Berkeley's Simon Relay Processor]