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The Electronic Numerical Integrator and Computer (ENIAC)

IP.com Disclosure Number: IPCOM000129913D
Original Publication Date: 1996-Apr-30
Included in the Prior Art Database: 2005-Oct-07
Document File: 10 page(s) / 42K

Publishing Venue

Software Patent Institute

Related People

H.H. GOLDSTINE: AUTHOR [+3]

Abstract

It is our purpose in the succeeding pages to give a brief description of the ENIAC and an indication of the kinds of problems for which it can be used. This general purpose electronic computing machine was recently made public by the Army Ordnance Department for which it was developed by the Moore School of Electrical Engineering. The machine was developed primarily for the purpose of calculating firing tables for the armed forces. Its design is, however, sufficiently general to permit the solution of a large class of numerical problems which could hardly be attempted by more conventional computing tools. In order easily to obtain sufficient accuracy for scientific computations, the ENIAC was designed as a digital device. The equipment normally handles signed 10-digit numbers expressed in the decimal system. It is, however, so constructed that operations with as many as 20 digits are possible. The machine is automatically sequenced in the sense that all instructions needed to carry out a computation are given to it before the computation commences. It will be seen below how these instructions are given to the machine.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

Copyright ©; 1996 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Used with permission.

The Electronic Numerical Integrator and Computer (ENIAC)

H.H. GOLDSTINE

ADELE GOLDSTINE

This paper was first published in Mathematical Tables and Other Aids to Computation just after the ENMC was announced in 1946. It was the major source of technical information about the machine for the scientific world of the time. Even today it ranks as one of the classic descriptions of the ENMC. This paper is reprinted in this issue by the kind permission of the American Mathematical Society and the National Academy of Sciences.

Introduction

It is our purpose in the succeeding pages to give a brief description of the ENIAC and an indication of the kinds of problems for which it can be used. This general purpose electronic computing machine was recently made public by the Army Ordnance Department for which it was developed by the Moore School of Electrical Engineering. The machine was developed primarily for the purpose of calculating firing tables for the armed forces. Its design is, however, sufficiently general to permit the solution of a large class of numerical problems which could hardly be attempted by more conventional computing tools.

In order easily to obtain sufficient accuracy for scientific computations, the ENIAC was designed as a digital device. The equipment normally handles signed 10-digit numbers expressed in the decimal system. It is, however, so constructed that operations with as many as 20 digits are possible.

The machine is automatically sequenced in the sense that all instructions needed to carry out a computation are given to it before the computation commences. It will be seen below how these instructions are given to the machine.

Description of the Machine as a Whole

The machine is a large U-shaped assemblage of 40 panels (see Figs. I and 2) which together contain approximately 18,000 vacuum tubes and 1500 relays. These panels are grouped to form 30 units (see Fig. 2), each of which performs one or more of the functions requisite to an automatic computing machine.

The units concerned mainly with arithmetic operations are 20 accumulators (for addition and subtraction), a multiplier, and a combination divider and square rooter.

Numbers are introduced into the ENIAC by means of a unit called the constant transmitter which operates in conjunction with an IBM card reader. The reader scans standard punched cards (which hold up to 80 digits and 16 signs) and causes data from them to be stored in relays located in the constant transmitter. The constant transmitter makes these numbers available in the form of electrical signals as they are required. Similarly, results computed in the ENIAC may

IEEE Computer Society, Apr 30, 1996 Page 1 IEEE Annals of the History of Computing Volume 18 Number 1, Pages 10-16

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The Electronic Numer...