if EWSLETTER VWA DIGITAL COMPUTER th t0 Noa it wwg W S W44 OPPiCif OP NAVAL IffifC wkii Ytd Nt 1 I MAMATATICALI_SCI EN-C 9S- DIVIIOW Y NI Api Ifr It It Iitt Ia I I m tt r io MoU tato ha hoto Aiis oai i rIo Itg ii 11 v n irwimiu o NIent Altortiooti I mlI llklr 11iti I 1h 1w -'' t capacityof 16 3 4 6a rydigi word Fuoliri introducingAtinforation 24-in t iintio thecomuerChtolc trically rea punch dy litape iae mp tloyed Imperia data may b oveIN tedf rom ecm alo roatobnr form inth mp11 terandCouitputo Mdata m be Vay coverh tedfom binoraryt eialfr n n o electric typewrite for % ty in sor t d onota aprtape pqunhif thedat r esd In orer toincreseiflexibieitofcntrl D ta cnommand wht ichth omuercnaryot r sin he fddres type0 wiethrovisu fomptr bu ws itencomeds Iyregneuingredmultip prociatsIonc toa Compniedttesloadi nmn the i t n ntorage0 adru cike in oplseratino es n eight einuesy maate AThoumgh mnoimdumacessry thime stothariheti 2n its ofIforomathen deru isqu32 incrh theimaximum stimaei deaterie y 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CONTAINED REPRODUCED FROM BEST AVAILABLE COPY BLANK PAGES THAT HAVE BEEN DELETED p T'he voneaior has I 'n very relltale ny spendlng ap priAletately 1 of ea6h day fur ro•tine lroevotiivo mgeigttnagne th 011vernmont hue olewrated the original t101 ttir the firstn BOO hinito with only 10 hewre of unotheod4itl l aineaeet M XHtl gVIIWOL AUTOMATIC C•OMPUThlt MOAC Work toa t'eiltni lnung• Iii tihe ealg acid ltmtlnil ot the Ieia ' e irou1i fi111 fioloa pilse tronealor11ero g41ti1ng te•'violoa and delay line itld Tl'he ini n vtoelal1'oea are nlteeiMn line Ittdlea A pleimi1iheery 1 eodlfikollon iof the lOgiW oaoed on the val1hbiiitip if the new v1irvuoit eti 11lotod wid 1itiming studles havo ihen g nduelod has been rl'oteyI 'io chaomols havo lboon von1trlcted and tmeed in the lotllnio progtrani T'hi e •n1nuit and holders tot the nmorpury-ioetlutI htkh eiepd 1att11ule y tanks e being aiukenublod 'ho phyptt'al laoout of the MIAC and nmethodo of iniler 'onlieoton are being otldiptlo ee the fieet v hawain 4uenetructieun 1# mehhduled for the month af June THEi INITITUTI-YOR ADVYAKID ITUIY C MPL TIIT alinca the puticatlon of thn last Nw 1eleter the me1moery organ for tho Institute fto Advanced Study computer hai boen completely integtated Into the syatem and variues teotl have been made Involving the Interplay of the arithmetic Andtmemory organii These tests are proceeding satlefactorIly During the ame period extensive life tata of the multiplier were completed Tiese teate were c¢rried out with the unit operating at a high dqty cycle and fully covered all aspects of the situation Various input-output organs are being built and tested at the preaent time 60 RDEEN PRO QINQ BOUND r MPI R The SNIAC completed its fifth year as an operating machine in February 1951 Gradual improvements have been made since the adoption of the converter code the most recent being a change in the address terininolog and an addition of a ainai unit to make automatic the switch between control from the function tables and control from cards During a recent period November 1950 to March 1951 the E NIAC completed the computations for the following problems a an investigation of sonie of the properties of interior baUlistict b an evaluation of error in axially symmetric supersonic airflow c two additional programs for the determination of the equilibrium composition of a four component system of fuel elements d two complete bombing tables e the reduction of data for 9 950 points of guided missile date and f wo programs Involving normal trajectory computations The EDVAC During tne period covered by the current report the 13DVAC system has been bru jht tu the condition of satisfactory operation with the exception of the momory amplifier assemblies The original are not considered satisfactory and new ones have been under construction and hive just been delivered It is hoped that the installation of the new memory amplifiers will conclude the conmotion and testing ot this unit eamplifiers 2- Te'ri t worgk %iltOw Of ttlAC 11Qnw11111olN pp r I tAlh hom Indiiialtd thlat oxteptliot ii rotbw 11t14i1i1t1Y in d he' P'4 1ii'llot fr ool this nquillillnt 11has ran for peor iiw of the tiu'itr i ons ttit o hours withimt Prl'i 1i '1111 1 tntvormiyit ' Ill in il Is isitrtuig livery effort it tewor sthr tholOe t elements of this 1114411111 will be Y10141t 1figtolmh It dliktisl l '0 th 11#1 Px hattativotv ' 1114011111ti loolod hafron the myntenm Is vonntplotod It appears that this poltry will itime thai would othorwise Ito piwsotblv ' duitato tOetoher I 0'i oiginallty Antli' iipatd will he rnot it 11101 10 1101111 101411 hiatlwfAVetty dovivo tit lopo NATIONAL Kit' IKAI or WANL ARDlS WKSTERNAU TOMATIC COMPUTICK SWAC li1poiwoienl itt tti v boont nlade linom tooting lochnlquuas and ntethodai of admjusting the nientury reoltilling Ili inouro vfiviolenut intenanco of th 3WAC aenorial toottng Ili still boing carried on inter- spo Iwed WAt tlhe11 kluolntg oit trohlonm I'wo owivtiml r iotor unitw for input are undor construction it large one for handling 1000 foot ret Iw ofpapot' tape And a sm aller une for handling shorter pieceN of tapeý A nmagiitivc tapi unit has been delivered from R'aytheon Corporation and York Is proceeding on its integration into the 3WAC Input-output mytemoi Prog ress is Olno being outdo onl the necessary circuitry to enable the magne-le drum memory to be useed noe an auxiliar l memory for the SWAC NA ioNLBUREAU OF STANDARDSEASTERN AUTOMATIC COMPUTHRj Z AC Statistien were com -iied on the operating performance of the SEAC for the montlie October through December 1980 lOuring the time which wasn met amddyl for the oolution of problems 76 hours per week the machine was in good working order for 64 por cent of the time In October 70 per cent of the time in Novernbe and 86 per cent of the time in December During the lasti week tin December the machine was in good wrrking order for 96 per cent of ths times A wide variety of problems have been run on the SEAC including the following Total Hours Problem on the Machine Brief Description Linear ProgrAmming OAC 525 Solution of large systems of linear algebraic equations pertaining to proilram planning for the Air Force Number Theoretical Problem 200 Computation of factorization tables tables of primes primitive roots of primes diophantine equations and Haupt exponents Determination of sample asies corresponding to minimum variance in a census using sampling methods Subgilknpling Design Census 68 Relative Abundance of Elements 48 Solution of a 27th-order system of ordinary differential equations relating to the neutron capture theory of the formation of the elements in the wtiiverse Electron Trajectories 40 Solution of asecond order nonlinear differential equa tion describing the passage of electrons through a cavity Laplace Equation by Monte Carlo Method 16 A test of the Monte Carlo Method by solving a known problem in two dimensions -3- Use has been made of two models of the new magnetic tape transport mechanism which require tin reelI or servos the tapes are held between parallel glans platem In this mechanism the only Inertia to be overcome when starting or stopping is that of the tape passing over capstan heads Reading writing and raverstl operations have been performed completely under the machine's control Equipment to provide selective erasure uwder maohine control Is now being developed The Williams tube memory designed for 1034 spots per tube in currently being proved in with 150 spots In order to obviate Rossible difficulties of splash read-around ratio The full Williams system was operated succoessmully on test routines for over five hours on two occauialn It has also worked successfully for several hours in integrated operation with the complete machine on A prime numborr routine This particular routine atorev orders and temporary results in the electrostatic moastry and does moat of thf%basic computation there in order to achieve increased speed With the electrostatic memory it took ItA minutes and 8 seconds to compute that 99 009 999 977 it a prime number with the acoustic memory the corresponding computation time was 36 minutes or three times as long A problem of significance in now being tried utiing both the acoustic and electrostatic memory in combination EKJQhE LWHIuiLkWW During January February and Maren the Whirlwind computer has been operating usefully with eluctrostatic storape One third of the time about 30 hours a week Is divided between scientific and engineering computation and the study of real-time control problems During these assigned application periods computer operation ti now satisfactory about 85 per cent of the time The other twothirds of the time is devoted to im- roving reliability extending the terminal facilities and routine maintenance Whrlwind is at present using 256 registers of electrostatic starage Input is by means of punched paper tape A photoelectric tape reader has been received and will shortly be connected to the computer to increase the speed of reading in programs and data An output typewriter is in use for printing computed results An oscilloscope display Is available for problems more readily studied by this means A magnetic tape drive has been received and circuits are bAlng built for its incorporation into the computer RELAY DIGITAL COMPUTE R PERIAL COLL EGE UNV OF LONDON K D Tocher is building an automatically sequenced digital computer at the Imperial College of Science and Technology The operation of the computer is drlal and a three-address code sinllar to the one originally devised for the National Physical Laboratory ACE pilot model is used Addition of two ten-binary-digit words takes approximately a quarter of a uecond round-off multiplication takes approximately three seconds Exact multiplication and double length operations on words can also be performed Division will be automatic Approximately 1800 high-speed relays and 1200 slow-speed relays are used in the computer both for the erasable memory elements and for the gating elements This rather large number of relays Is due M the inclusion ut several special facilities which can be called for automatically and not to the size of the erasable memory store which can hold only twelve words of ten binary digits each A slower auxiliary store is provided by punching equipment and Hollerith tape Standard Hollerith punched card machines are used in the input and output equipment From I February 1951 ONR European Scientific Notes In July 1950 a sequence-controlled computer was installed at the Institute for Applied MathematioN of the Swiss Federal Institute of Technology at Zuricl It was constructed by Konrad Zuse of Neukirchen Germany in consultation with E Stiefel and A Speiser of the Institute It is a relay computer with 2200 telephone relays and 20 step switches and employs mechanical storage elements developed by Zuse Although the storage capacity is now only 61 numbers It is hoped that it can be increased to 1024 numbers Access time to the memory Is one-half second The machine operates in the binary system employing a floating binary point with exponent ranging front 63 to -U3 Translation from decimal to binary numbers and vice-versa is fully automatic Numberr are fed in by means of keyboard or punched 35-mm movie film whereas the output p•es to a typewriter or punched film which can be fed back to the film-read unit thus providing external storage For introducing instructions Into the computer a coded sequence is punched into movie film each Instruction having 8 bLitary digits which is fed into one of two stations The computer executes the following nrders Add subtract multiply divide take the j% Are root form the absolute value call conditionally atop conditionally and unconditionally and skip conditionally The skip order causes all the following orders up to a starting order to be disregarded and thereby enables sevoral subsequences to be punched on one loop of tape The time for addition and subtraction is approximately I second for multiplication 2 5 sec for division and square root 6 see all including transfers from and to storage To skip an order takes 0 2 sec DATA HANDLING AND CONVERSION EQUIPMENT Stavid E•nineering Data Conversion Equipment Stavid Engineering Inc 312 Park Avenue Plainfield N J has developed a data conversion recurding and play back equipment which permits the measurements o servo orders to be made to an accuracy of 010 To maintain this accuracy the information contained in the servo order is converted into digital form at a pulse repetition rate of 60 000 pulses per second Two ring counters serve as both counters and memory circuits in order to slow the pulse repetition rate down to a frequency which is recordable on magnetic tape Nine servo orders are monitored and sequentially sampled at the rate of one order per twentieth of a second The measurements of the servo order are recorded on three-channel tape in the form of pulses On the first track one pulse is the equivalent of 01° of servo orders On the second track one pulse equals 250 and on the third track one pulse equals 100 Thus no more than 40 pulses are required on any track to fully define the measurement of the order Equipment is now being developed which will automatically accept the information from the magnetic tape and transcribe it into IBM punch cards where one card contains one measurement of each of the nine input orders Signal Corps Angular Position Encoders An angular position encoder to generate a 15-digit binary number which is a measure of the angular position of an input shaft to 010 has been designed at the Signal Corps Esngineering Laboratories Fort Monmouth New Jersey and construction of two models by a contractor is expected to be completed in March 1951 The heart of this device is a special code pattern consisting of transparent and opaque areas laid down on a glass disk 9-1 2 inches in diameter The pattern is made by -5- photographic contact printing from a suitable master The disk Is carefully mounted between berings and rotates with the input shaft An optical reading system consisting of a high intensity stroboscopic light source a narrow defining slit and fifteen miniature photocells will be used to 'read' the shaft position at regular intervals using a binary number sequence which provides freedom from transition errors and which is easily converted to the standard sequence The complete encoder including lamp photocells and photocell preamplifiers will be about 12 in diameter and 6 deep and will mount on any flat surface A ring-shaped flange is provided for centering with respect to the mount All delicate surfaces will be protected from dust etc and the whole asmembly is expected to be sufficiently lightweight and rugged for contemplated uses One application for this encoder is in connection with a digital servo for remote shaft positloning with very high accuracy In preparation for the construction of such u servo an experimental pilot model operating with 10-digit optical encoders was constructed at the Signal Corps Engineering Laboratories and completed in June 1950 Studies are now being made of the dynamic behavior of the 10-digit servo The major components of the 10-digit pilot model accommodate fifteen binary digits permitting their reuse as components of the high-accuracy servo after completion of the 15-digit encoders Zatocoding Zatocoding Is the name given by the Zator Company 79 Milk Street Boston 9 Massachusetts to its system of coding punched information cards for efficient machine selection by subject The process employs the technique of superposition of random subject codes indentations on the edge of the card It is not necessary to store the cards in any alphabetical or other subject order or to select references according to a definite classification scheme Copies of an occasionally published journal dealing with the problems of th organization of knowledge can be obtained from the Company upon request Comments letters to the editor and additional contributions for inclusion in the Newsletter should be addressed to Code 434 Office of Naval Research Navy Department Washington D C -6-