John W. Mauchly

Preparation of Problems for EDVAC-Type Machines

Perhaps it is in order to comment on the fact that there are now a large number of people interested in large-scale calculating machines. To Professor Aiken, as well as to others of us who have been campaigning for large-scale machines for quite a while, that is one of the remarkable and important features of this meeting. It shows how interest is — to use the expression someone used a little earlier — “snowballing.” Interest in such a field is bound to gather momentum as more people learn of its potentialities.

The Use of High Speed Vacuum Tube Devices for Calculating

There are many sorts of mathematical problems which require calculation by formulas which can readily be put in the form of iterative equations. Purely mechanical calculating devices can be devised to expedite the work. However, a great gain in the speed of the calculation can be obtained if the devices which are used employ electronic means for the performance of the calculation, because the speed of such devices can be made very much higher than that of any mechanical device. It is the purpose of this discussion to consider the speed of calculation and the advantages which may be obtained by the use of electronic circuits which are interconnected in such a way as to perform a number of multiplications, additions, subtractions or divisions in sequence, and which can therefore be used for the solution of difference equations. Since a sufficiently approximate solution of many differential equations can be had simply by solving an associated difference equation, it is to be expected that one of the chief fields of usefulness for an electronic computor would be found in the solution of differential equations.

The advantages of built-in checking

Electronic computers save money. That is the basic economic fact behind all of the current activity in the designing and building of information-processing systems. The job of the engineering designer is economic as well as technical. He must balance many factors as well as he knows how in order to achieve maximum utility at minimum cost.

The Advent of Electronic Computers

The earliest known electronic digital circuit, a “trigger relay”, which involved a pair of valves in a circuit with two stable states and was an early form of flip-flop, was described by Eccles and Jordan in 1919. (An unsubstantiated claim [1] has however been made that J. W. Bryce of IBM investigated the application of electronics to business machines in 1915.) The next development that we know of was the use by Wynn-Williams at the Cavendish Laboratory, Cambridge, of thyratrons in counting circuits including, in 1932, a “scale-of-two” (binary) counter [2]. By the end of the decade quite a few papers had been published on electronic counters intended for counting impulses from Geiger-Muller tubes used in nuclear physics experiments.