k D IG ITA L CO0M PU TER %oj ýo 1 i - Ii'bj -is wo1owide a aWodl am h1Zwdne ' 5 1 r i 7Jhfl OFFICE OF NAVAL RESEARCH I 00 61No h 4 lc •in 6t I d l_ m Nlwm i i - MATHIEMATICAL SCIENCES DIVISION 1 May 1950 t 2 No 2 CX05-P-64 TABLE OF CONTENTS I Naval Proving Ground Calculators 2 Raytheon Computers 3 Univac 4 Aberdeen Proving Ground Computers The California Digital Computer Institute for Advanced Study Computer Project Whirlwind 5 6 7 8 9 10 ii 12 13 U ' I fi 1 OfT I G 19G9 Maddida Computer Institute for Numerical Analysis Computer NBS Computer Computers Manchester University England Telecommunications Research Establishment Computer BARK Computer Sweden NAVAL PROVING GROUND CALCULATORS -- - r a This domcu cn a lid5boniV The Aiken Relay Calculator Mark Ht has been in continuous productive work at the Naval Proving Ground Dahigren Virginia since September 1948 Since January 1950 it has been operated 24 hours a day five days a week A number of new circuits have been added to the machine since its delivery to Dahlgren one of the latest being the installation of read-back checking devices on all input and output value tapes The Mark III Calculator was delivered to the Naval Proving Ground at Dahlgren during the month of March 1950 and is in the process of being reassembled The operating staff for the machine has been assembled from personnel who worked on the construction of the machine and two men transferred from other Proving Ground activities to this department The present staff of mathematicians is being augmented to take care of the programming for this new machine It is expected that Mark UI will be in productive operation by January 1951 RAYTHEON COMPUTERS The parallel adder for the thirty binary digit Raytheon Computer has been constructed and component tested System tests on the adder should be complete during May Production of the central control external memory and hunt circuitry is continuing Production of multi-channel magnetic recording heads has reached the level of fifteen 6-channel assemblies per month UNIVAC Inc The Eckert-Mauchly Computer Corporation recently became a subsidiary of Remington Rand Production schedules have been stepped up and two complete systems are being constructed CLEARINGHOUSL Ior ldLCII Sriont iic 10 1nical Inlormahtori Springliold Vi 22151 4 simultaneously These will be followed by a lot of at least three additional systems It is anticipated that production of the first lot will be completed and tested this year ABERDEEN PROVING GROUND COMPUTERS Enlac - This machine is in routine service During the past month it has been available for comofficmeryputation i e free from electrical and mechanical dtffigultrs 8u of the time The utilization ofuleoanihne re 67wro The difference baeween the two figures in brought about by the loss of time rie- y quired to set the machine up and also loss of time due to programming errors Edvac - The design of an interim Input-output system for the Edvam utilizing teletype tape as the transfer medium is complete Construction of the equipment required foir this cype of operation is well under way THE CALIFORNIA DIGITAL CCUPUTER Construction of the first units of the California Digital Computer has been completed and reliability tests of these units as a system will begin on May 1 1950 These units comprise the memory drum operating on one four-channel 200-sector band the sector counter and sector coincidence gates the reading and writing circuits for four-channel operation the timing circuits ad the first of the arithmetic registers Completion of the band switch and construction of the address register and the second arithmetic register which will Include the adder is expected by July 1 and performance of addition routines should be possible at that time The arithmetic registers will be used also for reading the input tapes and loading the drum The input tape-reader in bread-board form has been constructed Intensive study of programming and preparation of input tapes will begin this summer INSTITUTE FOR ADVANCED STUDY COMPUTER Since the publication of the last Newsletter the principal emphasis has been placed by the group at the Institute for Advanced Study on the fabricat' -i of the memory organ Now virtually all of this fabrication has been completed and the final assembly of the unit is well under way The initial testing of the memory is being started and the results will be reported in the next Newsletter Now that the design and construction of the memory organ are nearly finished attention will return to the arithmetic organ Here it remains only to assemble a few control chassis for the division operation and to start engineering and life tests comparable to those made for the multiplication operation PROJECT WHIRLWIND All of the Whirlwind I is operating except electrostatic storage and terminal equipment The first bank of 16 storage tubes with all associated circuits have recently been installed and are expected to operate in the computer by June or July Initial minimum terminal equipment will include two Eastman Kodak reader-recorders perforated paper tape -and typewriters TrL'sfer between tape and film will first be through the computer input-output register Additional photographic film units direct connection from film to tape and typewriter magnetic erasable storage and more electrostatic storage capacity are to be added during the following year An accelerated life test at high heater temperature seems effective for predicting vacuum tube susceptibility to cathode interface formation Work is progressing on coded preptratory3 programs to enable the computer to accept teletypecoded information from tape convert that information to proper binary form as an order or a number iaurum • •I --_ -_y ired subroutines and adapt them to their assigned storage locations 3 • ' 4-2 I - MADDWA COMPUTER The Northrop Aircraft Company has developed for the Air Force a new electronic computer the Magnetic Drum Digital Difterential Analyzer Maddida T L 5 tz th± - l cal y i• i tmu-uuve ordinary uiterenuai equations Careful design taking lull advantage of the special-purpose character of the device has resulted in Lmachine employing sixty-eight vacuum tubes and one magnetic drum which neverthelessposseuses the inte ting capacity of a tweaiy-two integraior differential analyzer Very satisfactory reliability of operation has been obtained INSTITUTE FOR NUMERICAL ANALYSIS COMPUTER All of the chassis of the arithmetic unit have been completed and are now in the process of being tested Two-thirds of the memory unit has been completely assembled and checked The control unit has been in operation for some time and has performed satisfactorily in connection with the testing of the arithmetic and the memory units The input and output circuits have been completely designed and are under construction at present The power supply has been installed tested and found to be satisfactory The ventilating system for the machine is now being installed In order to expedite the completion of the computer the machine will be first put into operation with 256 words of electrostatic memory This will be increased to 512 words as soon as practical since all the necessary additional chassis for the arithmetic unit etc have already been constructed In addition to the electrostatic memory which consists of standard cathode ray tubes it Is planned to install an 8192 word magnetic drum to serve as an auxiliary memory for the machine NBS COMPUTER The central portions of the computer including the control arithmetic and 512 word acoustic memory units have been constructed and assembled In addition the electrical input-output circuitry or shift register which allows matching asynchronous external-machine pulse rates to the megacycle repetition rates of the computer has been constructed and installed Currently the machine is being debugged and simultaneously a three-tube 32-word prototype electrostatic memory system is being completed for trial with the computer The machine assembly using punched paper tape input-output equipment is sufficiently advanced to permit making test runs using such subroutines as 1 decimal to binary conversion and 2 keeping a tally of repetitive muitiplications It is expected that an experimental magnetic wire input and a 10-channel prototype high-speed output printer using a photographically recorded cathode ray tube display will be available for test with the computer early in the summer COMPUTERS MANCHESTER UNIVERSITY ENGLAND An interesting feature of the Manchester computer is the B-box which is used to provide a convenient way of changing orders An order consists of three parts a so-called 'B digit an address in the memory and a code to represent one of 32 operations to be performed on the number in the given address The B-box stores two lines of information designated B0 and Bi If the BI digit of a given order is 0 the contents of B0 normally 0 are added to the order before it is executed if the IBI digit is 1 the contents of BI are added In the performance of a certain sequence of operations on various sets of data for example the sequence need be programmed only once containing the addresses of the first set of data and the addresses of later sets of data can be indicated by inserting a line in B1 The programmer is thus provided with a means of modifying an order just before it is executed and yet leaving it unchanged in the memory A second essentially similar computer is being built for the University by the Ferranti Company Limited of Manchester This computer will store about 20 000 digits in the electronic CRT memory and about 250 000 digits in the magnetic memory Its speed will be about 1-1 2 titmes that of the present -3- computer which adds two forty binary digit numbers in approximately 1 8 milliseconds and multiplies in a maximum time of 40 milliseconds TELECOMMUNICATIONS RESEARCH ESTABLISHMEIr COMPUTER Digital computer research at T R E Malvern is directed by Dr A Uttley Operating in a parallel mode the computer under construction will employ the F C Williams cathode r ay tube and ireufts for high speed storage with a magnetic drum for auxiliary storage A 2048 tooth phonic wheel coupled to the drum will act as a master clock for the electronic circuits thus solving the problem of synchronizing the drum with the rest of the computer A novel two-wire system is employed in which a positive pulse on one wire represents a on a while a positive pulse on the other represents zero The absence of pulses on both wires or the presence of two positive pulses indicates an error or a machine failure BARK COMPUTER SWEDEN The BARK Binir Auto-Matisk Reli-Kalkylator the relay computer mentioned In the last News- letter has been completed and has performed satisfactorily during continuous runs of up to 8 hours at speeds of about 200 milliseconds per addition and 00 milliseconds per multiplication It is hoped that by further trimming the speeds which are adjustable by means of potentiometers can be increased somewhat Containing about 5200 relays the machine cost less than $100 000 including design developments and construction The project was under the direction of Dr Conny Palm and most of the design work was done by Harry Freese and Gosta Neovius Comments letters to the editor and additional contributions for inclusion in the Newsletter should be addresseu to Code 434 Office of Naval Research Navy Department Washington D C - 4- 51 14120