DIGITAL COMPUTER TTERE - ARWSLR SOFPICE OF NAVAL RESEARCH MATHEMATICAL q SCIENCES DIVISONN Vol No a Ua 0 July IU51 1 1 VAL D 44cation 1 Tho ttay'thsal Digital COrnputor 4 4 The National flkiveat 4 14tandav'da bKantern Autom atic Comip%%tet % whiriwind I MA iT 6 The OIIDVAC UnWv of ILl 7 Moore School Automattic Cotmputer MNAC It Tho Institute for Advancod St%%dy Ctmiputer SPECIAL PURPOSE COMPUTERS 1 The CRC 101 Digital Difteuontial Analyser A Vie MAI DIDA I lyngAUXILLAiK AND CONVXRSION EQUIPMENT A Conversion and Display Equipmentr F UOCT 161969 Purromiago Eaborator Computer Since February 21 1051 the 3urroughs Adding Machine Company has been operating in the Philadelphia laboratories of its Research Division an electronic digital computer of unique construction This machine which has a magnetic-drum memory and teletype Input-output facilities was assembled entirely from general-purpose electronic building blocks Almost all of these generalpurpose units belong to the line of equipment known as Pulse-Control Units for which a descriptive brochure is available on request Sach Pulse-Control unit in a standard logical component such as a flip-flop gate or pulse5delay circuit and is equipped with input and output buffers Waveforms on the coaxial cables which interconnect units are restricted to two standard types 0 1 -microsecond pulses and two-valued d-c control voltages having 0 2-microsetcond switching time Use Of Pulse-Control Units permitted assembly of the computer directly from logical diagrams without the usual Intermediate engineering steps Only nine months elapsed from inception to completion After assembly and interconnection of approximately 500 units the computer was made to THIS DSOCUMEN BEST TS QUALITY AVAILABLE TIE COPY FURNISHED TO DTIC CONTAhNED A SIGN7IICANT PACEP 0ICH NUMBER DO OF NOT REPRODUCED FROM CONTAINED DocU4ENT THIS PAGES THAT HAVE BLNK BEST AVAILABLE COPY BEEN DELETED work In it entirety within 41 huora total accumulated time on the d-o supplies Tlh oheok-out of the power system time Included The na•chine'n present repertoire Includes It instructions which are sufficient to make it a foenerae-pur ose Ceomputer Until now multitplieaioneand division have been programmed but soil ic• tin•e in progress will make 11-i mingle inetructions A siegle-addresp code is normally used Wet a recent change permit a p •tranmmed choice between single- and double-addresa operation Moot Iill-a4dreaa4 operations require one magnetic drumn revolution I e 10 mtllteeconds for cnmpletion The program Is normally stored on the drum Number representatlnm ts binary-coded decimal exceas three Itorage is ssrial-ierial on the dram but aerial-parallel in the magnetic shift-regtuter accumulator A wont check is employed weighted moduloa- count of bits The form of unittied oonstruction employed here affords an additional degree of freedom which makes this machine uniquo not only can Itbe programmed both the internal workings ol the machine can be and have been modified readily by easily accomplished changes in plug-in connections without great concern over electronic details This computer has been operating during normal working hours since February 21 with about 81% trouble-free availability UNIYVC Dedication On June 14 1951 the formal dedication ceremonies were held In Philadelphia by the Bureau of the Census National Bureau of Standards and the Eokert-Mauchly division of Remingtton Rand Inc at which ttme the Secretary of Commerce Charles Sawyer accepted the first UNIVAC system for the Census Bureau Dr Ray V Peel Directr of the Census Dr Edward U Condon Director of the Bureau of Standards Mr James H Rand President of Remington Rand Lt OGe Leslie R GrovW V Pros of Remington Rand and Mr Albert M Greenfield President ofGreater Philadelphia Chamber of Commerce took part In the ceremonies as did Dr S N Alexander of the Bureau of Standards 1 A McPherson of the Bureau of the Census and 1 P Eckert Jr of the Eckert-MIachly division of Remington Rand The firpt UNIVAC system passed government acceptance teats in Aftrah and has been in almost continuous use by Census personnel since the first of April It is operated twentyfour 14 hours a day seven 7 days a week The second UNIVAC system is now nearing its final test and the third UNIVAC system ts going through itm initial test All of these systems are identical in design and construction differing oely in the amount of auxiliary equipment which varies according to the needs of the user The selfchecking facilitie of the UNWAC system have shown themselves to be highly Important and desirable This is the first large digital computer system to be manufactured on a production basia The Raytheon Digital Computer The clock central control main memory and the hunt rack are now In the system testing phase The external memory rack and the problem preparation data transfer unit have been unit tested and are now undergoing rack tests Twenty-six chassis not yet Included in rack tests have been unit tested whale seven chassis are undergoing qnIt test Eleven chassis have been fabricated awaiting uni l test thirty-nine chassis are in fabrication with the last one scheduled to be delivered early in August Optimization of the circuitry of the remaining twelve chassis of the computer is now being completed and the fabrication of these chassis is schedul4d for completion in August Magnetic tape defects have been reduced considerably by tape manufacturers These defects where not removable will be positioned In dead spaces between blocks on the magnetic tape A pulse transformer capable of passing a 10-microsecond pulse with 5% droop and having a 0 02 microsecond rise time has been developed and Is utilized In certain circuits of the arithmetic unit Present plans call for operational testing of the complete machine to be underway in October -2- A lIrP variety of problems have been run Nucgusfdluy of the SCAC devoted to problem solution enceeded 1000 hours during the months January Total operating time through March 1151 The Williams tube memory has been setioam on a supersonic nsoale problem operated successfully with 356 spots for several 6-hour Ingineering test show that the system %'%t the Maximum machine-call-rats of one word every 46 microaecondsm does can be adjuated stored Informatitm The Williams not interfero with problem in dynamics Involving twomemory has also been used muocessfully with Oit spots on a degrees of freedom which enncerns the tit apparatua related to airplane safety of sensIt In now being tried out with 513 construction with the acoustic memory on a problem spots In conjunction requiring the full capacity of both memoriss A punibed'card-to-magiotic tape converter has been built and used successfully for the WCOOP problem Whirlwid M IT Durin April May and June the Whirlwind computer beele for 35 hours been assigned to computation a week Of this asstled time 89 perhas cent has been trouble-tree Theon Whirlwin taff is timing 348 registers of electroatatic address storage operations per second A photoelectric and computing at a speed of 30 000 single reader provides paper tape INput at a speed of fifty 16-digit worda per second A group of 15 mathematicians cine an- In preparing and operatingand eonneers are engaged in planning the operation of the mabooe at the oragansation co the group programs for scientific and engineering computation A fteaUDSAC people by which all general is the development of techniques similar to thoe used by the programs are performed rsolts or symptoms recorded by an applications the coaiputer and the perator without any knowledge of the on given programs In addition to the above group there is another group of 16 mathematicians and engineers doing anmlysis wad preparing programs for government applications TsORDVAC Univ of 111 The arithmetic unit and the controla for the arithmetic completed The electrostatic for the ORDVAC have been memory containing forty 3KP1 orders tubes has for 24 hour periods without error but in test runs stared patterns been carried out The memory has no read around ratio test of the entire forty tubes has as yet been installed recently on the arithmetic error free for short periods of several hours in that location The standard unit and has operated teletype Input-output equipment has been completed The group is now engaged ponents which will be necessary Infortesting the memory and constructing the memory control comthe combined operation of the memory and arithmetic unit A Moore School Automatic Comuter JIU AC The development of the basic circuits are being completed and final design memoranda are being written These will appear in future issues of the MBAC progress reports A stirvey of the timing tolerance was carried out and a decision made as to the number of clock pulse phases required The physical and electrical layout of the logical elements of the machine has been started as well as the packaging of the plug-in diode assemblies The construction of racks and chassis it now underway along with the assembly of portions of the memory system -3 - Tho nstipule for Advanood otuk m2 ter As this account to being written the control organ of the Institute for Advanced Study Computer is undergoing Its final tests in the machine The oily remaining parts are the divider the teladoltod%unit which Is now being fabricated and a few minor Oci mnups of various chassis now In place The CRC 101 Dijital Differential Analyzer A CRC 101 Digital Differential Analyser wait completed recently by the Computer Research Corporation of Torrance California This machine is a mobile unit weighing about 330 poun includiit power supply and occupying approximately the space of an office' desk It Is applicable to a wide range of computation toot and control problems and can solve any problem that can be put in the form of ordinary differential equatiuaiu linear or non-linear It has 50 Integrators and each of'them can integrate the algebraic sum of up to 15 variables with Wespect to any other variable Control of CRC 101 is from a remote operating panel which may be placed at any desired dislance from the rmachine The control panel is the also of an adding machine Input data may also be read into the machine from external sensory devices or graph followers and the output may be in the form of a plotted graph typed numbers or control over some type of effector Connections are provided for these purposes The computing section of the machine contains 102 vacuum ubes and 1743 germanium diodes The memory uses 21 tubes Power requirements are nomuinl The machine ts filled by means of typing in initial conditions and tke'grator connection codes with two adding machine type buttons Integrators and channels are selected by control knobs While the machine functivas in the binary system read out at the remote control panel is in the octal notation The memory for CRC 101 Is a magnetic drum which can store in excess of 7000 digits with drum speed 3600 RPM Computation speed is 3900 incremenlts of the independent variable per minute The MADDIDA Copies of the 44-integrator MADDIDA called the MADDIDA 44A whose development was mentioned in the 1 August 1950 Newsletter have been completed and are now In operation This computer employs a magnetic-drum memory combined with a computer unit Although the fundamental operation is numerical integration integrators can be so operated as to perform other operations such as addition comparison and multiplication Esk entially integration of the equation z -J ydx is performed by repeated addition However the block diagram of the solution of a differential equation or system of equations on the MADDIDA is similar to that on an analogue differential analyzer During computation information is transmitted between integrators in the form of incremental changes in variables Each integrator has a dx input through which it receives incremental changes in an independent variable x a dy input through which it receives changes is a dependent variable y a dz output through which it delivers incremental changes in the integral z The source of dx may be the output of any one of 42 other integrators or its own output or any one of 12 empirical input channels The source of dy may consist of the algebraic sum of from one to seven of the above -4 - soarces in any combination The dy input may also be oriitted when using the Integrator as a constant multiplier In cases whore the equation is such that dx must also consist of the sum of several channels an additional integrator Is used coded as a simple adder Computation within the computer is done in the binary number system since this leads to more compact and reliable circuitry This means that initial conditions must be typed into the computer an binary or octal numbers however uutput devices are available which will tabulate the results of MADDIDA computations directly in the decimal system The desired interconnections between integrators are easily expressed as a binary code and this code to typed into the computer along with initial conditions The 'vetusl interconiv otion of Integrators io done fully automatically in the machine's electronic circuits While many functions can be generated within the computer by solving auxiliary differential equations itis at times convenient to insert purely arbitrary or empirical data into the computaktion For this reason 12 empirical input channels are provided in the machine These input channels may be fed from various input devices One such arrangement is now being made available as a graph follower with which graphical data are semi -automatically placed on perforated tape A number of btpo may then be simultaneously fed into the computer through these input channels while competation proceeds The independent variable or speed of tape advance io under the control of the computer 3top functions may also be inserted at pro-set intervals with such apparatus J-5 Also provided in MADDIDA are 12 output channels A tabulating printer which will accumulate and print result ' decimally and an automatic plotter to present results qraphically are available for operation from these channels There are many other devices whic can be developed that will operate from these channels The Integrating device consists of two registers Y' and 'R and a tray sfer device T 1 When a dx pulse is applied to T Y In added to R and the ds outputs are pulses representing overflows from R Hence the rate of di pulses overflowing out of R is proportioaal jointly to y and to dxt du ky dx Of course at any time y - yo Zidyi The memory drum uses six channels One of these is a permanently recorded clock channel which keeps the machine in synhronization Two channels hold the Y and R Information corresponding to the two registers already discussed Two more channels which are referred to as %I1and 11L1 2 contain hook-up information and specify what problem is being solved A sixth chaonl referred to an the Z line in used for intercommunication between integrators and transmite this Information in accordance with the data contained in the L ch annels AUXILIARY AND CONVERSION EQUIPMENT Flying Typewriter Potter Instrument Company Inc 115 Cutter A411 Road Great Neck N Y announces the development of a new high-speed line-at-a-time printer Driven by a flexible electronic shift register the 'Flying Typewriter' will print over 300 lines per minute Each line consists of 80 columns of alphanumeric characters Forty-seven different alphanumeric and special characters are used Printing is on standard 17 -ounce teletype paper and several carbon copies can be made cnThe vacuum tube shift register in addition to being used as a loading device for the printer cnalso be used as an 80-column arithmetic accumulator for calculations Although primarily designed for coded pulse and magnetic tape input it can be adapted to print from punch cards perforated paper tape keyboard and other means Conversion and Display Equipment Recent contributions to the computer field by the Benson-Lehner Corporation 2340 Sawtelle Boulevard Los Angeles 64 California Include the following' 1 A D C -to-4e tmal converter for feeding from strain pug potentiometers ate directly to tape punch cards typewriters The system has no electronic counters it involves the Analog Digital Converter see Newsletter of December 1950 and in accurate to one part in a thousand 2 Denuon-Lehner Dactylograph an x-y plotter for desk use with 11 x 17 inch paper having independent x and y scale and origrin adjustment A variety of inputs may be used according to model type including the following hand-operated keyboard D C voltages IBM output MADDIDA upuL and others -Comments letters to the editor %i• additional contributions for inel'sion in the Newsletter should be addressed to Code 434 Office of Naval Research 'AVAII1LoAIIcT A Navy Department Washington D C AVI 4