DIGITAL COMPUTER NEWSL7ETTER-W' z OP IC9 OF NAVAL RI19ANCH MAH_______ P lDIISO 1 V if 4 Nit I April 1051 TANl Or ONTUNTS I l t 4 Whit 1 1 1t I ONH Ielay timillpilor t o Tbh o• V Thme 4Cs'' Cý t 1 M ro cho A't'b lo ii Cmiptiu N Chb UNIVAQ IAITI1h01 4 r'ho J aoe h lu company 10 The 1AflA 11 Consolidf l t 1 The AG0 MSAC C ompulora JAINCOMP Elotrattic D ilita Computer Model O- l Pilot Modeln r0 D OCT 1 61969 Whirlwind I1 lino the middle of January the Whirlwind computer has been using a second bank of 16 storage tubes Bank B that operate at a density of 32 x 32 spots Good reliability haa been obtained from these 1024 new registers As theme new tubes become available they will also be installed in Bank A The over-all reliability of the computer continues to be high about 90% During 1951 proventive maintenance procedure led to the removal of 473 vacuum tubes of about 0 000 in service before failure had occurred Only 22 vacuum-tube failures 16 of which were from shorts or opens interrupted the operation of the computer Experience with crystal rectifiers also hu shown an improvement A comparison of total crystal failures during 1951 with those of 1950 shows a decrease of 124 or 0 5 percent per thousand hours This decrease is noteworthy a the 1950 failure rate was only 1 percent per thousand hours The total number of component replacements during 1951 other than vacuum-tube and crystal replacements was 47 The percentage of failures per thousand hours for these miscellaneous components was approximately 0 02 the same figure an for 1950 To the paper-tape input system has been added an interim magnetic-tape system for which programs are being prepared The tape reader uses 0 heads grouped Into 3 pairs the heads in each pair scanning duplicate channels in order to eliminate errors due to blemishes in the tape On January 19 over half a million 16-digit registers were recorded and checked during a period of three hours without an error A1 'I N - H 0 H t kI DISCLAIMERýN THIS DOCUMENT IS BEST QUALrTY AVAILABLE Tha COPY FURNISHED TO DTIC CONTAENED A SIGNIFICANT NUMBER OF DO G AE 51 1rH 1 Ji- F ROD UC7' L NOT ILY REPRODUCED FROM BEST AVAILABLE COPY THIS DOCUMENT CONTAINED BLANK PAGES THAT HAVE BEEN DELETED Tholoomeearv 10511 Newnifellr lialvil fivo 00110ral 111 1111101110 ams 11mllngtilmhod Iroilsec ia lI mil worked oni pr lwinsto attelleokt %ilitl WAhi glwitwi 1 i h 'a tinptio ruble Ilary wtorhj whie'h aie % in% Itvgwhe r with the' eteoilmstti or aspne' that iIIIU ti le 1110111 SI the fol lowins 1 urpodo dopiit rpPfilO#noP Nivriiie' N'ea ngiu'i'r1%e Maictl iillfu tIII 1pin litt ii' mdia IKe'lovrivoa K14111W01 ing IYcirothormii elocivire' myotein Mloirecivai I 411ninesriclV i11111M 111411l itv 01%t heilp likil-4241 '%1 $11111us VJwe c' Auto- anci Cc' pem e'ur rpatitlie cfttolliomilo Mltirtierloiy oil refIIng1 proiclecminh tnualr ial Anslycecs of ooeiicsneie dali ineoil leevalloct Oeeelaey Matlhý Analysics ofl rsivao Mathocteallem tVryptal Pe mteruemua 'leitt Kipe'tcieal Kniiliitioeiiiig Aircraft Oustloicads Avrot Knilinooring Internal viiemvlenutic onsinoo Moceh Knifiiceeing rotip-notweerkcst atistiecs Kt'ocnenelea Sehroodinger wave equalton iPhypilva Nivetrivlea Eng Shoar wells Civil Kniginooring lit addition lto the iegular itlaeluini pc'ngrani lit digital computers M I T will offer in July 1051 eAcspecial intensive lwo-wook aunicuer apacelen lit Digital Comnputer acid their Applications Included lin lh courrse will lice a survey if applicationsm and logical structure A#well an a detailed troatment of programming tochniquoit oniphaieslaing the use of various kinds of subroutines in facilitating the preparation of knd the location of mistakes lit program The Instr'uction will be by members of the M I T Digital Computer Laboratory staff The Whirlwind computer will be used to provide group denmonstration and individual praetical experience The ONRRelay Computer An a result of arrangements mado by the Off ice of Naval Research a general-purpose comnputIng machine was permanently installed lin Staughton Hall on the mampus of The George Washington tintvermily on 9 May 1951 At that time it wasn renamed the ONR Relay Computer and was loaned for operation and maintenance to the Logiatice Rescearch Project which in under ONR contract at the University The machine is a low-speed relay computer with magnetic-drumn storage of 4 01 4 numbers each consisting uS 24 binary digits equivalent to about seven decimal digits It is capable of performing 39 arithmetic logical trarnsfer and output commands through use of 734 mechanical relays and 655 electronic tubes The multiplication time ic1 2-1 2 seconds Input to the computer in by mechanically sensed seven-level teletype tape while output may be on punched tape or by electric typewriter Control Is of the single-addres type Tape preparation duplication and print-out typewriter equipment were also delivered with the computer Below are examples of programs which have been run during the past few months 1 At this writing the Project is computing quarterly mian-power requirements implied by a proposed shipbuilding schedule Given the building dates and total manpower requirement of a ship a fourth-degree polynomial Is evaluated to distribute the man-hour requirements into yearly quarters These requirements are summed for the fleet 2 A calculation was done for the Air Force determining the amount of fuel required in an operations area Data included the number of each type of plaice in the area the expected flying hours and figures for fuel consumption per hour 3 The computer has been used for the preparation of input tapes of Marine Corps allowance lists for the Logistics Computer a special-purpose electronic computer being built for ONR by Engineering Research Associates Inc It will be delivered late in 1952 for operation by the Logistics Research Project 4 A program was prepared for the iterative solution of games by Brown's method each player having as many as 20 strategies Several hours were spent on the computer solving a stample Lrame 2- The A The Autniatllo linary Compuler ABC of the Air Iwefene Office oa the Air Force Canlbrldlo Research Center 230 Albany lito tr Cambridti 30 Mausechuoetta ina lenriral purpsmo foui- addresm miathine with serial maitmtit'-drlon memory and parallel arithmetle unit Drum 'lwart'llty is 4 0 h fty-alx bit word i Data are handled Internally in pure binary form with provisin fon' the computer' to chvrrt Input data from decimal to binary and output data from binary to denimal Alternatively data oan be inserted and removed in octal form Initially Input-output will be by electric typewriter with tiap Input-output projected for the future The medlum-speed arithmetic unit will multiply two fifty-six-bit numbers in 1 100 mlarroaecondie The present drum%system with uverage access time of 10 mnicroeconds in the limiting factor of oyer-all computer speed it was used because it was immediately available This ooess time will be greatly reduced In practice by coding techniques The logical design of ABC is complete construction and trouble shooting are in progress In December 1951 an additional control unit for operation of SEAC In the three-sddress mode was built and ts being installed It features a counter to generate the address of subsequent instructions in a subroutine and has provisions for resetting the counter to any arbitrary memory posilion at the end of a subroutine This means that a subroutine may be coded without reference to actual positions in the memory in which it in stored and therefore the same subroutine may be used in one part of the memory for one problem and in another part of the memory for another problom with only minor modifications It in anticipated that this feature will aid in the utiliation of a library of subroutines and thus increase the usefulness of SEAC by reducing the time of problemsolving The Williams memory is now in regular operation with 512 spots It is scheduled for approximately 40 hours of operation per week and has been utilised for nearly 500 hours of useful computation Its reliability is now better than that of the acoustic memory when SEAC was first put in operation a year and a half ago but is not as good as the current acoustic system The most valuable use of the Williams memory has been on large problems for which the unchanged constants and instrucUons are stored In the Williams memory and all variable factors and results are stored in the acoustic memory The information stored in the Williams memory is checked periodically by comparing its sum with a previous sum of the constant terms to detect possible error The combined use of the two memories haI proved both fast and effective The SWAC The lowering of the accelerating voltage on the Williams-tube memory system was reported in the last Negasletter The installation of a delay system to minimise difficulties with respect to read-around ratio and the installation of the motor generator set to stabilize voltages and minimize adjustments have paid off In an increase in operating time on the SWAC The electrostatic memory still predominately uses 5JP-type tubes with their high incidence of flaws but with these tubes it is possible to operate regularly with read-around ratios of 40 to 1 and only a few units fall to operate at approximately 100 to 1 Two 3-inch tubes made under the BuShips contract at RCA have been in use during the last quarter with very good results A Continuing effort is being expended on improvements of the present Williams-tube memory During this quarter two new Mersenne primes 2521 the SWAC -3 - - 1 and 2607 - 1 were discovered by IC '1uli r The' t110'0 1r'lftheliMttons fill the' AatIadaril l rihltithion n1odilep of this machine Newplultor for October I001I are now fairlyv vimiple• and soles privo and delivery time havew ben satabflamhed by the manufavituror ollnan t aWbitoriorlm Itith Perry Sttrop Now York 14 New York Moore' Schl-lot Aollmtoiati Computo'r MSlAC The of tiw n impatch'er Mriory l•dop of thp MSAC has been completed It has ont1urttn uned1'tont'tmieatt aitd dynamic' tcstA antd hitk Puet vodeod lin performinlng all its logical funot ons Thls un1it was buill und to'ntd %ild1ran Inthrint prtegra•n otitablahod for the purpose of obtaining final p'rforn1#n Ig uf 'nfration on the Iaetc v1ir1uit1 in ord 1' to 1make any modifications of the circuitry that natiy •w nee'tnnry 1in addition the tin1e roquti'ed lit the construction and testing of this unit will give an accurateh Indihatito•if tho timel reqoired to complete and toem the entire machine An interim power supply voaihining ain P'lootronics ly I•oguhlated Thyratron supply and a storage-battery supply hta bwen cot lmlht ld totfoglhor with an outoniatic' charging unit to keep the battery voltags within dtolign toleratnv•m Work 1 e cont'•i'iig on the drawing of che1matics ind the procurement of parts The UNIVAC Acceptance tests have been pastied on the second UNIVAC system and it is in the process of thiiz installed for the Office of the Air Comptroller The third UNIVAC system is rapidly nearing conmpletion and hhould be ready for acceptance tests very shortly The Jacobs Inat uniettComiaiy Computers LAJNCOMP The JAINCOMP computers are all-parallel electronic asynchronous computers suitable for both control and computational applications Work on these computers was started in the late spring of 1949 The first machine JAINCOMP-A was completed and tested in the early spring of 1950 This machine weighed 40 lbs It had a wired-in automatic program involving addition subtraction multiplication decision and the taking of sines It used punch-card storage for constants and flipflop storage for intermediate values It had one c'hannel of variable instrument input to demonstrate its usefulness for real-time control applications The second Jacobs Instrumeca Company computer JAINCOMP-B was started In the fall of 1950 and completed in the fall of 1951 This is a compact device 16-1 2 x 21-1 4 x 30 inches weighing 110 lbs It handles 24 binary digits and adds two 24-digit numbers in eight microseconds It uses toggle-switch storage of two microseconds access time for constants which are changed from problem to problem For high-speed storage it oses a very compact magnetic system having a maximum storage time of eight microseconds and a maximum access time of four microseconds for a 24-digit word The machine has subcontrols for such processes as addition subtraction multiplication division finding sines and are sines and cubing The original JAINCOMP-B machine had four wired-tn programs each involving solutions of t7 - lifferent algebraic equations In February 1952 a flexible general-purpose programming system was added to the computer This modified machine is called JAINCOMP-B Company representatives state that it has shown very groat reliability Also in oLruaryan ultracompact magnetic storage device was designed and tested A device for converting a shaft rotation to a binary computer input was developed in January 1951 Accuracies of a few seconds of arc appear obtainable with this type of device Readings can be made at any desired rate up to about 200 per second and can be fed directly into a computer at these rates The ADAC The CADAC was delivered to the Air Force Cambridge Research Center in January 1952 It is now located at the Massachusetts Institute of Technology on an indefinite loan It was shipped to Cambridge by air and rail express and was placed in operation within two weeks after its arrival It has been operated as of February 16 over a two-week period During this time only one machine error occurred while operating for an average of four hours per day for ten days -4- For IW Mt of this period the computer has been used in training the maintenance personnel who will be in charge of the machine and in accustoming the users to the techniques of programming The following problempt have beon iolved on the computer M A decimal-to-octal and octal-to-decimal conversion 2 Solution of eight simultaneous linear equations Plans ar under way for an improved version of the CADAC making pos isible decimal input and output with the computer doing its own conversion A Flexo-Writer unit will replace the present keyboard and typewriter so that punched paper tape can be utilized as input for repeatable problems In addition an auxiliary storage magnetic-tape unit automatically controlled by the computer will replace the manual tape unit Certain other design Improvements will be made Computer Research Corporation is also building two other computers One is a la ger faster completely decimal general-purpose computer with a large amount of flexible input-output equipment Thias machine CRC 107 will handle business applications as well as scientific problems since It can accept and print alphabetic characters digital differential analyzer primarily designed for utmost convenience The second is a eL cgl to the user and with a complete set of printing plotting and empirical-function input-output equipment Consolidated Electronic Digital Computer Model 30-2' 1 Consolidated Engineering Corporation 300 N Sierra Madre Villa Pasadena 8 California has under development a moderate-size general-purpose digital computer The main memory is a magnetic drum with a capacity of 4 000 words A quick-access memory is also provided with a total capacity of 80 words Special commands are provided which accomplish the transfer of blocks of 20 words between the main memory and the quick-access memory The computer employs a single address command system The number length is eight decimal digits plus algebraic sign fixedpoint operation is normally employed The binary-coded-decimal notation is employed In the design of the computer reliability and ease of coding are emphasized The power consumption will be less than 6 kva and the floor area occupied by the computer will be approximately 2 ft by 8 ft A special feature not ordinarily included in general-purpose computers of the intermediatespeed type is the B-register This register has been included to facilitate the coding of iterative operations When a command is coded as a special command the contents of this B-register are added to the address portion of the command before it is executed Special provisions are made for increasing decreasing and changing the numbers stored in the B-register In many cases the computer may be supplied its input information numbers by automatic datahandling systems such as Consolidated's SADIC and MILLISADIC analogue-to-digital conversion systems If the computation program has been previously stored on the magnetic drum the results of the computations can be obtained within seconds after the original measurements The ACE Pilot Model The ACE Pilot Model has been designed and constructed by the Electronics Section National Physical Laboratory Teddington England in collaboration with members of the Mathematics Division and a number of engineers and technicians from the English Electric Company Its main features are still as described In the December 1950 issue of the Newsletter but the control system has been improved and an automatic multiplier added also new adjustable-length reflectiontype mercury delay lines have been designed and constructed and will replace the existing straight-through lines rhis machine was built solely to gain experience before designing the ACE itself and is therefore very inadequately furnished with check and maintenance facilities It has proved however to be a very fast and efficient computing machine and the immediate requirement for high-speed -5 - computation is such that anything that can be madt to work must be made use of It will therefore be maintained in service while the ACE is being designed and constructed In fact a fully engineered version of it is now contemplated as the next step since this could be produced in a relatively short time Meanwhile auxiliary magnetic-drum storage is being added to it to secure the necessary capacity for large-scale problems The ACE Pilot Model was designed for a 2-address code in order to simplify its construction but the ACE itself will have as originally intended a 3-address code with a consequent substantial gain in over-all computation speed but there is not at present any intention to change to electrostatic storage The acoustic delay-line storage as now designed is robust reliable and very insensitive to external disturbances It is commonly assumed that its relatively long access time as compared with the Williams cathode-ray system is a serious disadvantage but this has been largely obviated in the Pilot Model by a logical design which permits optimum programming This is perhaps the most interesting feature of the machine An example of the gain in speed obtainable In this way is Wrovided by the problem quoted in the Newsletter for April 1951 The demonstration thaf 99 999 999 977 is prime took SEAC 36 minutes using delay line storage and 12 minutes 8 seconds using the Williams C R storage It was done on the ACE Pilot Model which has the same pulse rate as SEAC and similar delay lines in 7 minutes 45 seconds in spite of the facts that the shorter word length of this machine necessitated doublelength arithmetic procedure and that the machine has very limited arithmetic facilities which do not include automatic division The average rate at which the 2-address instructions are carried out in this problem is 13 000 per second Data-Handling Devices Telecomputinrg Corporation 133 Bast Santa Anita Avenue Burbank California announces its new voltage-to-digit converter known as the Teleducer The device consists of an electronic servo system providing an accuracy of one part in 127 with a minimum useful input of one volt full scale and output in binary digital form The Teleducer is completely electronic and its binary scaling rate of 25 kc permits it to follow voltage variations equivalent to a 40-cps sine wave never lagging by more than one count Another new development of Telecomputing Corporation is its magnetic reading head which converts shaft rotation into digital form by directly without gearing dividing each revolution into as many as 10 000 counts The magnetic reading head is a completely ac device thus avoiding the usual problems of dc amplifier drift Toleplotters are currently being delivered at the rate of three a month with six now in service The Teleplotter will provide extremely accurate graphical output for a variety of types of digital computers although thus far its use has been limited to punched-card and manual-keyboard input cFrTi WHITE SlEION CQ $OFFSECTION Doc UKAPIOUNCED TIF TION By 01 I omments letters to the editor and additional contributions for inclusion in the Newsletter should he addressed to OISTPIBUTION AVAILAlLITY COOES 'I T AmtI 'Id ' SPECIAL Code 434 Office of Naval Research Navy Department Washington D C -6- ¶ c•1is1