DIGITAL COMPUT E R TI Iof TTI T ry I I i5 Z4 OFFICE OF NAVAL RESEARCH ' i Zotoo Co ' ' 7ro fdnlo ct l¢pvJel MATHEMATICAL SCIENCES DIVISION December 1950 Vol 2 No 4 NAVEXOS-P 645 1 Z 3 4 S 6 7 S 9 10 TABLE OF CONTENTS The Naval Research Laboratory Computer NAREG Moore School Automatic Computer MSAC Naval Proving Ground Calculators SEAC Formerly call-4 N3S Interim Computer Aberdeen Proving Ground Computers Coupling of IBM Relay Calculators The ENIAC National Bureau of Standards Western Automatic Computer SWAC The Institute for Advanced Study Computer Ptoject Whirlwind Z r 3 Thl ACE Pilot Model Teddington England Data Handling and Conversion Equipment Digital Reader i OCT Digital Data Recording System Analog Digital Converter T 1 199 Nfl COMPUTE R NAREC it the U11i dr the directihntit D II Co'idhey an utoml ntie electronic dlf•itnl r'mUUtor 'oientiug t 'Iat the Naval • 6-enrh Ltnt rntory l'1rhitypen of mol t if lite rittparalle'l initio hast beon designed cal contlinents have been built and checked A tentative cormpletion date haq been -40 for the %itunitr of 1952 Employing about 2000 vacuum tube envelopes and 6000 crystal diodes this computer will possess 1024 words of electrostatic Williams tube memory and 2048 words of magnetic drum memory The word length is 45 binary digits Magnetic tape will be used for the input-output medium In order to check transfers and other operations a built-in functional checking systeym will be employed In the electronic circuits in place of the standard flip-flops a modified Schmidt-type trigger circuit is being used Research on preliminary models of the adder indicates that not counting memory access time two 45 binary digit numbers can be added in approximately 3 microseconds Access to the Williams tube memory is expected to be on the order of 10 microseconds The control has been designed to employ a one-address order code MOORE SCHOOL AUTOMATIC COMPUTER MSAC Concurrently with a research and development project on components of electronic digital computers sponaored by the 5ignl Corps Engineering Laboratories Department of the Army the Moore School of Electrical Umginerlng University of Pemisylvania i engaged In the design and construction of an electronic digital computer The logic of this machine the MIAC will be patterned after that I Rprd -d by t CLARiNijOUEfor fo SciOtIIIkic TechricmI rFdrl rrwlt Swringimold V-n 22151 -e • puhp utt - O tlICPPlovedI it - ' t 1 AC which Was dtciiw nd ind cons tructed -it thr' Moore School for the Ordnance Depirtrncnt W rk ot1rrxidhoar d do lm i t a rd in Februiary 1950 and k %chrdulod to pe rmit const ruction of major unit 11i1 I h 1 Ii thi p'ting of 1951 -h'Ir 1 hno continuod to expand Its offering in the field of lnrrec scale computing dovices and tochniqur- since the first such course was presented in ieuv Irne ioiiowing coruinum '64 this fivid are offered 'Introduction to Digitnl Computing M achines by Mr Goodman Diigital Computers - Logic' by rrnfcissor Patterson Digital Computers - Enrineering by Professor Rubitioff 'Continuous Variable Coiuvs yPoesrDlhsa 'niern Mothods for Solving Differential E quations and NAVAL PROVING GROUND CALCULATORS The Aiken Relay Calculator Mark 11 continues to run on at 24-1tour day f ive-day week schedule on Bureau of Ordnance work or on problems submitted by other Government activities During the past six months only minor circuit changes have been made Thbrise result in some simplification of coding The operating and maintenance staff is now up to complement with six operators and eight assistant operators who hrndle both operating and maintenance duties The Mark III Calculator has been reassembled and Is undergoing tests It is expected to be in a production status by January 1951 SEAC Formerly called NBS Interim Computer All of the chassis for the second memory electrostatic have been completed and installed and production of the plug-in components is nearly complete Operating tests are now under way using the completed parts of this memory with the comi-'ter Magnetic recording has been successfully used In productive computation for the initial loadIng of the machine's memory- It is not yet ready to operate completely under the machine's control A new magnetic tape transport has been built which moves tape at 180 inches per second with acceleration times of the order of 10 to 20 milliseconds It uses no servos or tape reels During the month of October the machine was In good operating condition for 60 percent of the 76 hours per week which were allocated to computation This 60 percent represented the 43 percent of the totnl time during which useful problem solutions were being obtained and the 17i percent devoted to the checking of the coding of problems Three different codes for the Office of the Air Comptroller have been prepared and three models of programming were completed using these codes in about 150 hours of computation time A problem for the Bureau of Census on the determination of optimu'ii values for a subsampling design was completed with about 60 hours of computation time The Monte Carlo method was applied using both weighted and unweighted probabillity functions to a two-dimensional Laplace's equation A program for generating 500 random normal deviates was prepared and executed A problem of tracing 1400 dtifferent electron trajectories in an electromagnetic cavity was completed with about 8 hours of computation time Several codes have been prepared for the calculation of prime numbers and prime factors of numbers less than 1011 A mangnetic numeroscopo printer wats delivered to the National Bureau of Standards by EngineerIngl Roseinrel A 44ncinteq In Atrpust 1950 and demonstrated during the AssocintiOn for CnompuAting MRtrhi nory eonf renect Iin S 'piitombr 1950 This device IN An esiperim eidti l high-speed printting equ iptuent In Whiell Oliaratc1 ah tc kICISth ld -'lit iitally on then 4rt s0s of a icathmit -ray tulle The olectrott 1%am% which tit tho tracing is directed by character forming signals magnetically recorded on the surface of a rapidly rotating cylindrical drum The printing speed for the equipment as now constructed Is approximately 500 characters per second This rate may be increased to more than 4000 characters per second by modification of the present equipment The experimental model baa provision for tracing 10 different characters and itoi planned that the neAt model will be able to trace 40 different -2- ch arctr A photographic recording unit has been constructed utilizing a modified microfilming c amerat iprnoided w-ith a clutch for stopping film motion during idle periods An electronic keying unit permtni use of the prlnt r for recording the output of digital computers A r ' iFEN CCM '2 S Coupling of IBM Relay Calculators The storage capacity as well as the programming facilities of the IBM Relay Calculators have been enlarged recently by a simple device that effectively transforms the two identical machines into one computing device of greatly increased power This device is a properly designed connector cable that may be connected or disengaged from the machines at will When operating in tandem operational control is exercised entirely by cards through the use of class selectors Depending on the complexity of a particular problem the machines are now being employed either singly as before or jointly in the manner indicated above The coupling device has already been used repeatedly and with very satisfactory results The ENIAC During the past two and a half years the ENIAC has been controlled by the two-digit single address Converter Code Some 37 problems have been completed on the machine during this period with an over-all effective operating efficiency of 54 percent The code as incorporated during this period performs the arithmetic operations with 10 decimal digit numbers at the following rates Additions 800 see subtractions 400 see multiplications 200 eec and divisions or square roots 35 sec These figures are slower than the original design figures for the ENIAC because of the restrictions of the code however the greater ease fn putting on new problems the additional capacity of the machine and the higher operating efficiency make the sacrifice in speed Justifiable NATIONAL BUREAU OF STANDARDS WESTERN AUTOMATIC COMPUTER SWAC This computer formerly known as the Institute for Numerical Analysis Computer was dedicated on August 17 The formal dedication was followed by a one-day symposium on applications of digital computing machines to scientific problems which are being studied by West Coast laboratories and universities at the present time Final plans for the SWAC include an intermediate-speed auxiliary memory consisting of a magnetic drum and a slow-speed auxiliary memory consistrIng of a magnetic tape unit It is planned also to supplement the present Flexowriter input-output unit with a magnetic tape system as soon as possible Work is proceeding on the design and construction of the chassis needed to integrate these new units into the SWAC computer system The computer has been used for problems orligiinating with the research staff of the INA such as a problem of Dr Kae's involving the generation of random digits and for problems originating with the United States Air Force THS INSTITUTE FOR ADVANCED STUDY COMPUTER Since the publication of the last Newsletter the complete memory organ for the Institute for Advanced hludy Computer hns boon given extensive life tests Those tests were sattsfactory and on the basis of them the final control chassis for this organ has been built In addition this organ together with Its control equipment has been attached to the machine itself put tin During the same period various parts of the arithmetic and control organs were fabricated and place With the help of these extenilve engineering and life tests were made -3- aJ PROJECT WHIIRLWIND Durinr August and September each storage tube digit column was more carefully tested and ndI watg thin provlimialy h-sr hA-- prLe M It -S I I------m aad chocking methods and facilitins developed comparable to those in the other sections of the computer Thok fall torn registration Iin the MIT Automatic Computation and Numerical Araiyshi dournes listed In the last Newsletter averages twenty students The Servomechanisms Laboratory hats begun study of three-dimensional high-speed storage wherein selection of a storage cell occurs at the Intersection of three coordinate planes of a solid array Storage may be in either ferromagnetic or ferrc'electric cells Several new staff members have been added to the mathematics and coding group which to studying problems arising In 1MI research projects THlE ACE PILOT MODEL ENGLAND The Electronics Section of the National Physical Laboratory Teddington England was formed in 1947 to undertake In collaboration with the Laboratory's Mathematics Division the design and construction of the electronic digital computer known as the ACE Because of the size and conmplexity of this machine it was considered desirable to build first a smaller Pilot Model which would provide valuable experience in design and programming for the ACE itself This Pilot Model has been virtually completed and is now working It is a serial machine operating at a pulse repetition rate of 1 megacycle per sec and uses about 800 tubes mounted on some 40 plug-in units The internql Moemory is of the supersonic delay line type It has 8 long lines each with a delay of 1024 microseconds and 10 short lines each with a delay of 32 microseconds giving a total storage capacity of 264 words each of 32 binary digits These are either numbers or instructions In a 3 address code Access timie varies from 32 - 1000 microseconds Experimental work is proceeding on the design of a magneticdrum storage system which will supplement the delay line storage and greatly increase the scope of the machine Input and output organs consist of modified Hollerith punched-card equipment The Pilot Model has been used for a number of simple problems such an the evaluation of the integral of 1 l x2 from 0 to 1 integration of Dessel's equation for 1o and tabulation of primes up to 128 000 using a program division routine It has also been used to solve a problem posed by Dr Wijngaarden of the Mathematical Centre Amsterdam who needed to know whether the number 150 450 047 999 was a prime The machie found the two factors 1319 and 114 0S3 721 each of which is a prime When fully completed and tested the Pilot Model will be transferred to the Mathematics Division of the National Physical Laboratory for regular use while the ACE itself is being built DATA HANDLING AND CONVERSION EQUIIPUENT Digital Reader Arthur D Little Inc Cambridge Massachusetts has developed a digital reader which will read a continuously varying voltage and convert it to digital numbers of 6 binary digits At speeds up to 12 cycles per second the binary numbers can be punched on standard IBM cards with the standard IBM key punch Readings can be taken at frequencies from as low as one per few hours up to 50 000 per second High speeds would require recording on magnetic drums or tapes or on photographic film At low speeds accuracies of 14 binary digit numbers or at hitth speeds accuracies of 8 binary digit numbers are possible Digital Data Recording System The Metrolype Corporation Chicago Illinjois has developed a recording system which automatically records data in tabulated digital form The oldest Installation has been in comnmorcial op eration about 2-1 2 years The input Is normally In the form of voltage and may be on low as 5 volts or as high as 200 volts for full scale Items to be maeasured are selected in turn by a circuit selector and quantized into pulses by a step voltmeter which produces pulses proportional to the voltage Theme pulses are counted by electronic counters held aill tramilated to teletype code andpulnited by a standard teletype printer A 3 decimal dirit measurement requires about 0 8 second The printer may be remotely located Various supplementary features such as totalizing range shifting multiple printers alarms auto matically punched tape and carbon or ditto copies can be provided Retranstultier are available to permit connection to self-balancing recorders or servos to provide highly accurate columnated records of multiple readings of temperature flow pressure and other quantities A more aetalied description el this system may oe iound in the paper 1nhe Metroiype System oi Recording and Telemetering by G E Foster Electrical Engineering May 1950 Analog Digital Converter The Benson-Lehner Corporation has available an Analog Digital Converter designed to convert shaft rotations into discrete digital form and to round off the output information to within one-half of the last significant figure For example if the primary input to a three-decade converter unit wore 355 8 revolutions the output would be 356 it the primary input were 355 4 the output would be 355 In accordance with the needs of the user any number of decades can be used A combination of mechanical gearing and electromagnetic selection is used to proptigate number changes through a multidecade unit The present unit can handle 5000 number changes per second Driving torque roq 'ired for the conviorter tL approximately 1 5 tnh-mune The converter can be used to record automatically information from strain gauge output thermocouple readings fluid level changes theodolite film records and other data sources The converter can also be used to transform digital information into analog form for example a number coroespending to 231 of shaft rotation can be set up in the converter circuit and the converter will drive the input shaft to this position An arrangement such as this can be used as a form of digital servo one unit transmitting shaft rotation ii digital form and the other receiving the digital informat' on and establishing the corresponding shaft position The converter can be used to operate IBM punched-card machines or electric typewriters In the caue of a typewriter the information from each decade 's sampled sequentially e g by a stepping switch while for an IBM Summary Punch it is necsssesy to take the data from all of the decades in parallel The typewriter keys are operated by smcat solenoids installed under the regular keyboard in such a manner as not to interfere with normal •ypewriter use The Benson-Lehner Corporation has developed a variety of specialized equipment in the field of automatic data analysis including such devices as automatically operated plotters tabulators and • -- i onic reversible counters which will accumulate i ssaAMd tabulate the total in the decimal system ' Comments letters to tho editor and additional contributions for In elusion in the Newsletter shotld be addreaued to Code 434 Office of Naval Research Navy Department Waahington D C i i ii