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EDVACEDVAC Electronic Discrete Variable Automatic Computer MANUFACTURER Moore School of Electrical Engineering Univ. of Pennsylvania OPERATING AGENCY U.S. Arry Ordnance Corps Ballistic Research Lab, APG GENERAL SYSTEM Applications Solution of ballistic equations, bombing and firing tables, fire control, data reductions, related scientific problems. Timing Synchronous Operation Sequential A general purpose computer which may be used for solving many varieties of mathematical problems. NUMERICAL SYSTEM Internal number system Binary Binary digits per word 44 Binary digits per instruction 4 bits/command, 10 bits each address Instruction per word 1 Total no. of instructions decoded 16 Total no. of instructions used 12 Arithmetic system Fixed-point Instruction type Four-address code Number range -(l-2^{-43}) <= x <= (l-2^{-43}) ARITHMETIC UNIT Add time(including storage access) 864 microsec (mib 192 max 1536) Multiply time(includ.ing storage access)2880 " (min 2208 max 5552) Divide time(inclu~.ing storage access )2930 " (min 2256 max 3600) Construction Vacuum-tubes and Diode-gates Number of rapid access word registers 4 Basic pulse repetition rate 1.0 megacycle/sec Arithmetic mode Serial STORAGE Micros sec Media Words Access Mercury Acoustic Delay Line 1024 48-584 Magnetic Drum 4608 17,000 Includes relay hunting and closure. The information transfer to and from the drum is at one megacycle per second. The block length is optional from 1 to 584 words per transfer instruction. INPUT Media Speed Photoelectric Tape Reader 942 sexadec char/sec 78 words/sec Card Reader (IBM) 15 rows/sec 100 cards/ndn OUTPUT Media Speed Paper Tape Perf. 6 sexadecimal char/sec 30 words /min Teletypewriter 6 sexadecimal char/sec 30 words/min Card Punch (IBM) 100 cards/min 800 words/min NUMBER OF CIRCUIT ELEMENTS Tubes 3563 Tube types 19 Crystal diodes 8000 magnetic elements 1325 (relays, coils and trans) Capacitors approx. 5500 Resistors approx. 12000 Neons approx. 320 CHECKING FEATURES Fixed Comparison - Two arithmetic units perform computation simultaneously. Discrepancies halt machine. Paper tape reader error detection. PHYSICAL FACTORS Power consumption, Computer 50 K.W. Space occupied, Computer 490 sq ft Total weight, Computer 17,300 lbs Power consumption, Air Cond. 25 K.W. Space occupied, Air Cond. 6 sq ft Total weight, Air Cond. 4345 lbs. Capacity, Air Cond. 20 tons MANUFACTURING RECORD Number produced 1 Number in current operation 1 COST Rental rates for additional equipment I.B.M. card reader $82.50 per month I.B.M. card punch $77.00 per month Approximate cost of basic system $467,000 PERSONNEL REQUIREMENTS Daily Operation No. of Tech. 5-8hour shifts 8 7 days/week No engineers are assigned to operation of the computer, but are used for design and development of improvements for the computer. The technicians consult with engineers when a total break-down occurs. RELIABILITY AND OPERATING EXPERIENCE Average error free running period 8 hours Operating ratio O.7'9 Good time 130.5 hrs. (Figures for `55) Attempted to run 166 hrs./wk No. of different kinds of plug-in units 3 No. of separate cabinets(excluding power and air cond.) 12 Operating ratio figures for 1954: Operating ratio 0.79 Good time 129 brs. Attempted to run 163 hrs./wk ADDITIONAL FEATURES AND REMARKS Oscilloscope and neon indicator for viewing contents of any storage location at any tine. Exceed capacity options: halt, ignore, transfer control, or go to selected location. Unused instruction (command) balt Storage of previously executed instruction and which storage location it came from, for viewing during code checking. Storage of current instruction and storage location from which it originated. Address halt when prescribed address appears in any of 4 addresses of instruction to be executed by computer. Tape reader error detection.

ELECOM-50ELECOM-50 Electronic Computer 50 MANUFACTURER Underwood Corporation Electronic Computer Division Long Island City 6, N.Y. GENERAL SYSTEM Application Commercial Timing Synchronous Operation Sequential NUMERCIAL SYSTEM Internal number system Decimal Decimal digits per word 10 plus sign Total no. of instructions used 42 plus combinations Arithmetic system Fixed-point Number range .000001 to 99999999 ARITHMETIC UNIT Add time(excluding storage access) 650 microsec Multiply time( " " " ) 39,000 microsec Construction Vacuum-tubes Number of rapid access word registers 3 Basic pulse repetition rate 67 kilocycles/sec Arithmetic mode Serial 650 microsec is one minor cycle. Multiply requires 60 mmnor cycles. STORAGE Micro sec Media Words Digits Access Main Drum 100 1000 33,000 Working Registers (Drum) 3 30 325 INPUT Media Speed Keyboard Manual Paper Tape 20 dec dig/sec OUTPUT Media Speed Gang Printer (2) 10 char/sec Paper Tape 2 dec dig/sec Printers operate in parallel. NUMBER OF CIRCUIT ELEMENTS Tubes 160 Tube types 5 Crystal diodes 2000 29 PHYSICAL FACTORS Power consumption, Computer 2 K.W. Space occupied, Computer 50 cu ft 20 sq ft Total weight, Computer 750 lbs. MANUFACTURING RECORD Number produced 2 Number in current operation 2 Number on order 16 Delivery tine 14 months COST Approximate cost of basic system $17,000 with one carriage. Additional equipment Continuous-form Carriage $1,000 Rental rates of basic system $55O/month Rental rates for additional equipment $100/month PERSONNEL REQUIREMENTS One operator required for each shift of operation. RELIABILITY AND OPERATING EXPERIENCE Average error free running period 6 hours No. of different kinds of plug-in units 42 No. of separate cabinets (excluding power and air cond.) 3 ADDITIONAL FEATURES AND REMARKS Simple operation Programing by manufacturer 10-key input 2400 Step program tape Interchangeable Program tapes.

ELECOM-100ELECOM-100 Electronic Computer 100 MANUFACTURER Underwood Corporation Electronic Computer Division OPERATING AGENCIES Reeves Instrument Corporation New York 28, N.Y. Fire Control Division Development and Proof Services Aberdeen Proving Ground, Md. GENERAL SYSTEM Application Guided missiles, aircraft Systems accuracy, Expansion of firing tables. Timing Synchronous, magnetic drum, Asynchronous, Magnetic Tape. Operation Sequential The computer at Reeves is owned by the Navy Bureau of Aeronautics and is operated by Reeves Instrument Company under Project Cyclone. NUMERICAL SYSTEM Internal number system Binary Binary digits per word 50 Binary digits per instruction 50 Instructions per word 1 Total no. of instructions used 8 Arithmetic system Fixed-point Instruction type Three-address code Number range ~(4-2^{-27}) to (4~2^{-27}) ) The eight instructions includes an "external operation," which, in turn, includes six different operations. Octal number system. ARITHMETIC UNIT Construction Vacuum- tubes Number of rapid access word registers 0 Basic pulse repetition rate 100 kilocycles/sec Arithmetic Mode Serial 25-50 operations per second may be performed, including drum memory access. STORAGE Microsec Media Words Access Magnetic Drum 512 20,000 max Magnetic Tape 60,000 One block of tape is equivalent to one channel on the drum (64 words), transfer or movement of one block takes approximately 2 seconds. INPUT Media Speed Typewriter (Flexo writer) Manual keyboard Paper Tape (Flexowriter) 7 1/2 octal dig/sec OUTPUT Media Speed Typewriter (Flexowriter) 7 1/2 char/sec NUMBER OF CIRCUIT ELEMENTS Tubes 223 to 240 Tube types 6 Crystal diodes Approx. 2200 The Aberdeen machine has 42 relays. CHECKING FEATURES Fixed Overflow indication (and halt) Out-of- syncbronism for tape (and halt) Engineering diagnostic tests PHYSICAL FACTORS Power consumption, Computer 3.5 K.W. Space occupied, Computer 120 ft2 MANUFACTURING RECORD Number produced 3 Number in current operation 3 The Elecom 100 at Aberdeen is the first one built by the Electronic Computer Division of Underwood. COST Approximate cost of basic system $60,000 + $2,000 installation. These figures are for the computing system at the Aberdeen Proving Ground. PERSONNEL REQUIREMENTS Daily operation No. of Eng. No. of Tech. 1-8 hour shift 1 1 RELIABILITY AND OPERATING EXPERIENCE Date first unit passed acceptance test 9 Dec 1952 No. of different kinds of plug-in units 5 No. of separate cabinets(excluding power and air cond.) 2 APG Computer has had 1471 hours of good time out of a corresponding total of 2225 hours attempted to run time. The Stevens Institute of Technology, Hoboken, N.J. has an Elecom 100.

ELECOM-12OAELECOM-12OA Electronic Computer 120A MANUFACTURER Electronic Computer Division Underwood Corporation Long Island City 6, N.Y. GENERAL SYSTEM Application Engineering, scientific Timing Synchronous Operation Sequential NUMERICAL SYSTEM Internal number system Decimal Decimal digits per word 10 plus sign Decimal digits per instruction 10 Instructions per word 1 Total no. of instructions decoded 53 Total no. of instructions used 33 Arithmetic system Fixed.point Instruction type Two-address code 10 Number range -(1-10^{-10}<= n <= 1-10^{-10}Figures are for basic model Floating -point optional Floating point coefficient range -(1-10^{-8}<= n 1-10^{-8}Floating-point exponent range -50 <= e <= 49 Floating-point operation, when supplied, is in addition o[sp] normal fixed-point operation. ARITHMETIC UNIT Add time(excluding storage access) 330 microsec Multiply time ( " " ) 18,300 microsec Divide time ( " " " ) 18,700 microsec Construction Vacuum-tubes Number of rapid access word registers 5 Basic pulse repetition rate 132 kilocycles/sec Arithmetic mode Serial Above operation times are for average 10 digit multiplier, dividend and divisor respectively. STORAGE Microsec Media Words Access Magnetic Drum 1000-10,000 8300 avg. Magnetic Drum 10-100 1670 avg. Main storage on single head per channel basis. Fast access storage are recirculating channels. GAFB has 250,000 word tape unit, 8 dec dig words for the Elecom 120. INPUT Media Speed Typewriter 8 char/sec Paper Tape 8 to 400 char/sec Magnetic Tape 400 char/sec Typewriter is standard equipment. High speed paper tape reader is optional. One magnetic tape unit supplied as standard equipment. Standard model includes controls for additional tape units. OUTPUT Media Speed Typewriter 8 char/sec Paper tape Punch 8 or 60 char/sec Magnetic Tape 400 char/sec Typewriter is standard equipment. High speed punch is optional. NUMBER OF CIRCUIT ELEMENTS Tubes 400 Crystal diodes 4500 These figures include some optional equipment. 5% of tubes are of 2 basic types. CHECKING FEATURES Fixed Internal check for forbidden pulse combina- tions and check of drum writing operations. Parity check on tapes, with automatic re-read. PHYSICAL FACTORS Power consumption, Computer 5 to 7 K.W. Space occupied, Computer 200 cu ft Total weight, Computer 3500 lbs These figures are for computer complete with control desk and one tape unit. MANUFACTURING RECORD Number produced 5 Number in current operation 5 Number on order 2 Delivery time 6 to 9 months. Figures are for type 120 which is the same as the 120A except for word length. COST Approximate cost of basic system $97,000. Rental rates of basic system Approx. $3,500. Rental rate is for complete system and includes maintenance. GAFB This Elecom 120 instaLlation cost $85,000 for basic system and $15,000 for 2 magnetic tape units and 1 Ferranti High Speed tape unit. PERSONNEL REQUIREMENTS Daily Operation Underwood: Engr. Oper. or Tech. One 8-hour shift 1 1 Two 8-hour shifts 2 2 Three 8-hour shifts 3 3 GAYB One engineer, 3 programers, additional personnel are required. RELIABILITY AND OPERATING EXPERIENCE Date first unit passed acceptance test March 1954 No. of separate cabinets(excluding power and air cond.) 2 Underwood Average good time being reported is 90-95%. Grifiss AFB Rome, N.Y. The Elecom 120 system passed acceptance test on 1 March 55. The average error free running period was 10 hours. Of 40 hours attempted to run time 17.6 hours were good time. These figures are based on a two month period following installation. No other figures were available, but since then the record has improved. Other users include: Westinghouse Aviation Gas Turbine Div. Kansas City, Mo. Shell Development Laboratories Houston, Texas ADDITIONAL FEATURES AND REMARKS The Elecom 120 has a word length of 8 decimal digits plus sign, basic pulse repetition rate of 105 kilocycles and an average tine for internal operations of 35 milliseconds.

ELECOM-125ELECOM-125 Electronic Computer 125 MANUFACTURER Electronic Computer Division Underwood Corporation Long Island City 6, N.Y. GENERAL SYSTEM Application Comercial, engineering, scientific Timing Synchronous Operation Sequential NUMERICAL SYSTEM Internal number system Decimal Decimal digits per word 10 and sign Decimal digits per instruction 10 Instructions per word 1 Total no. of instructions decoded 36 Total no. of instructions used 36 Arithmetic system Fixed-point Instruction type Two-address code Number range -(1-10^{-10}<= n <= 1-10^{-10}2 dec dig per alphabetic char Floating point optional 8 Floating point coeff range -(1-10^{-8}<= n 1-10^{-8}) Floating point expon range -50 <= e <= 49 Floating point operation, when supplied, is in addition to normal fixed point operation. ARITHMETIC UNIT Add time(excluding storage access) 330 microsec Multiply time(" " ") 18,300 microsec Divide time ( " " ") 18,700 microsec Construction Vacuum-tubes Number of rapid access word registers 3 Basic pulse repetition rate 132 kilocycles/sec Arithmetic mode Serial Above operation time is based on average 10 dec digit multiplier, dividend and divisor. STORAGE Microsec Media Words Access Magnetic Drum 1000 to 10,000 8300 avg. Magnetic Drum 10 to 100 1670 avg. Main storage is on a single head per channel. Fast access storage is a recirculation channel. INPUT Media Speed Typewriter 8 char/sec (Manual) Paper Tape 8 to 400 char/sec Magnetic Tape 2000 char/sec Typewriter is standard equipment High Speed reader is optional Punched card is optional, utilizing IBM 528 or similar unit. Magnetic tape synchronizing circuits are included as standard equipment. OUTPUT Media Speed Typewriter 8 char/sec Paper Tape 8 or 60 char/sec Magnetic Tape 2000 char/sec Typewriter is standard equipment. High speed paper tape punch optional. Card punch (IBM 523) or Tabulator (IBM 407) optional. NUMBER OF CIRCUIT ELEMENTS Tubes 450 Crystal diodes 5000 95% of tubes are of 2 basic types. CHECKING FEATURES Fixed Internal check for "forbidden" pulse combinations. Check of drum writing circuits. Parity check on tape, with automatic re-read. PHYSICAL FACTORS Power consumption, Computer 5 to 7 K.W. Space occupied, Computer 200 cu ft Total weight. Computer 5500 lbs. Capacity, Air Cond. 5 tons Space and weight figures are for computer (complete) with control desk and one tape unit. Room air conditioning is reconmiended. No built in equipment is supplied with system. MANUFACTURING RECORD Number on order 4 Delivery time 6 to 9 months Much of the internal circuitry is substantially the same as that of the ELECOM 120, of which 5 have been built. COST The price of a complete ELECOM 125 Electronic Business System including a complete assortment of input and output units, is usually of the order of $250,000. The monthly rental rate is approximately $7,500/mo, which applies to the entire system including the File Processor, Computer, Tape units and some optional equipment. This is based on a purchase price of approximately $250,000. The rental figure includes full time maintenance. PERSONNEL REQUIREMENTS Daily Operation Engr Oper or Tech. One 8-hour shift 1 1 Two 8-hour shifts 2 2 Three 8-hour shifts 3 3 RELIABILITY AND OPERATING EXPERIENCE No. of separate cabinets(excluding power and air cond.) 2

ELECOM-125FP38 ELECOM-125FP Electronic Computer 125 File Processor MANUFACTURER Electronic Computer Division Underwood Corporation Long Island City, 6, N.Y. GENERAL SYSTEM Application Commercial Timing Synchronous Operation Sequential NUMERICAL SYSTEM Internal number system Decimal Decimal digits per word 10 plus sign 2 dec dig/alphabetic char. Operates on "items" containing any integral number of words. Fixed program, switch selected: sequence, collate, select, select and collate separate. ARITHMETIC UNIT No arithmetic unit in the usual sense. STORAGE Media Words Acoustic Delay Line 100 Storage is five 20-word channels. INPUT Media Speed Magnetic Tape 6000 dig/sec Typewriter 8 char/sec Paper Tape 8 char/sec Typewriter and paper tape is used for checking and control. OUTPUT Media Speed Magnetic Tape 6000 dig/sec Typewriter 8 char/sec Paper Tape 8 char/sec NUMBER OF CIRCUIT ELEMENTS Tubes 290 Crystal diodes 5500 Over 85% of tubes are type 6AN5. CHECKING FEATURES Fixed Parity check on all data. PHYSICAL FACTORS Power consumption, Computer 7 K.W. Space occupied, Computer 150 cu ft Capacity, Air Cond. 5 tons Space figure is for processor, control desk and 4 tape units. Room air conditioning is recommended. No built-in equipment is supplied with system. MANUFACTURING RECORD Number on order 2 Delivery time 6 to 9 months COST Approximate price of basic system $60,000 (FP only) Additional equipment Tape d.rives $10,000 each. Rental rates of basic system $7,500/month Rental rate applies to entire system, including File Processor, Computer and Tape Units with some optional equipment, based on a system having a purchase price of $250,000, approx. Rental figure includes full time maintenance. ADDITIONAL FEATURES AND REMARKS An important partner in the ELECOM 125 Electronic Business System is the ELECOM 125 File Processor. This is an entirely separate piece of equipment, designed and engineered to handle the sequencing, collating, extracting and similar operations necessary in day-to-day business applications. The ELECOM File Processor extracts from the voluminous tLibrary Tapest, the particular items upon which processing is to be done. It is the job of the ELECOM File Processor to pick the pertinent items out of the magnetic tape file, so that the Computer wastes no time in searchingt through un- wanted items. Once the items have been processed by the ELECOM 125 Computer, the ELECOM File Processor puts them back into their proper place (in sequence) in the main file.

ENIACENIAC Electronic Numerical Integrator and Computer MANUFACTURER Moore School of Electrical Engineering Univ. of Pennsylvania OPERATING AGENCY U.S. Army Ordnance Corps Ballistic Research Lab, APG GENERAL SYSTEM Applications Solution of ballistic equations, fire control problems, data reductions, and related scientific problems. Timing Synchronous Operation Sequential NUMERICAL SYSTEM Internal Decimal in basic computer, binary coded decimal in magnetic storage Decimal digits per word 10 plus sign Decimal digits per instruction 2 Instructions per word 5 or 6 Total no. of instructions decoded 100 Total no. of instructions used 97 Arithmetic system Fixed-point Instruction type One-Address Code Number range 10^{-10}-1 to 1-10^{-10}ARITHMETIC UNIT Add time(excluding storage access) 200 microsec Multiply time(" " ") 2,800 microsec Divide time ( " " ") 24,OOO microsec Construction Vacuum-tubes Number of rapid access word registers 120 Basic pulse repetition rate 60-125 kilocycles/sec variable. Arithmetic Mode Parallel Information is transferred in parallel as a serial train of pulses. STORAGE Micros sec Media Words Access Vacuum-tubes 20 200 Magnetic core 100 200 Function table 304 lines of 12 dec digits + sign on each constant set-switch Plug board 96 lines of 12 dec digits + sign each (IBM) Relays 8 buffer capable of storing contents of one card INPUT Media Speed IBM Cards 125 cards/min Each card has 8 ten decimal digit words plus signs OUTPUT Media Speed IBM Cards 100 cards/mm 200 millisec of card cycle are available for other computer operations. At 50 cards/mm rate, 800 millisec are avail- able for computer operations per card cycle. NUMBER OF CIRCUIT ELEMENTS Tubes 17,468 Tube types 16 Crystal diodes 7,200 Magnetic elements 4,l00 PHYSICAL FACTORS Power consumption, Computer 174 K.W. Space occupied, Computer 1800 sq ft Air conditioning, Forced outside air. MANUFACTURING RECORD Number produced 1 Number in current operation 1 COST Additional equipment Magnetic storage $29,706.50 Rental rates for additional equipment: I.B.M. card reader $82.50 per month I.B.M. card punch $77.00 per month Approximate cost of basic system $750,000 PERSONNEL REQUIREMENTS Daily operation No. of Tech. 3 - 8 hour shifts 6 7 days/week A minimum requirement for operation and servicing on a 24-hour-day, 7-day-week basis. No engineers are assigned to operation of the machine, but they are used for design, development of improvements and consultation when total breakdowns occur. RELIABILITY AND OPERATING EXPERIENCE Date unit passed acceptance test 1946 Average error free running period 5.6 hours Operating ratio 0.69 Good time ll3 hrs. (Figures for 1955) Attempted to run 164 hrs/wk No. of different kinds of plug- in units 44 No. of separate cabinets (excluding power and air cond.) 42 Operating ratio figures for 1954: Operating ratio 0.70 Good time 116 hrs. Attempted to run 166 hrs./wk ADDITIONAL FEATURES AND REMARKS There are four modes of operation: Continuous, Pulse time, Add time, or Instruction time. A manual pre-set stop box is available. Count instructions and transfer instructions are used.

FERRANTIMARK-IFERRANTI MARK-I Ferranti, Ltd Ferranti Electric Mark I Computer MANUFACTURER Ferranti, Ltd Ferranti Electric, Inc. 30 Rockefeller Plaza New York 20, New York GENERAL SYSTEM Application Scientific calculation Timing Synchronous Operation Sequential and Concurrent The input/output only may be either sequential or concurrent. NUMERICAL SYSTEM Internal Number System Binary Binary digits per word 40 Digits per instruction 20 Instructions per word 2 Total no. of instructions decoded 32 Total no. of instructions used 30 -32 Arithmetic system Fixed-point Instruction type One-address code Number range -2 <= x < 2 Shift and standardize instructions provided which facilitate floating-point arithmetic. ARITHMETIC UNIT Add time(excluding storage access) 1200 microsec Multiply time(excluding storage access) 2160 microsec Construction Vacuum-tubes Basic pulse repetition rate 100 kilocycles/sec Arithmetic Mode serial There is a built in multiplier but no built in divider. The macbine normally operates on long (40 bit) words, but short (20 bit) words form instructions and B- lines. A manual facility switches in either 40 or 20 bit accumulator operation. STORAGE Microsec Media Words Access Electrostatic tubes 768 Magnetic Drum 32,768 31,200 The drum has 256 tracks and revolves at 1924 RPM. The CRT stores 15,360 bits. The drum stores 155,360 bits. INPUT Media Speed Paper Tape (5-hole) 200 char/sec One character is 5 bits. OUTPUT Media Speed Teleprinter 7 char/sec Tape Punch 15 char/sec Parallel Printer 150 lines/mm A 25 char/sec punch is being developed. The Parallel-Printer line consists of 64 alpha-numeric characters, with 92 printing positions on each line. The remaining positions print spaces and the locations of these in the line are pre-set by a plugboard. NUMBER OF CIRCUIT ELEMENTS Tubes 3300 Crystal diodes 1000 6AL5 (Double Diodes) 1500 EF5O, 5591 (Pentodes) 1500 12AT7 (Double Triodes) 220 Sundries 80 CHECKING FEATURES Optional Check facilities for transfers between drum and CET. storage and vice-versa. PHYSICAL FACTORS Power consumption, Computer 26 K.W. Space occupied, Computer 4000 cu ft 600 sq ft Total weight, Computer 10,000 lbs Air conditioning is built in. MANUFACTURING RECORD Number produced 7 Number in current operation 6 Number on order 2 Delivery tine 9 months These figures include two machines of an earlier Mark I design. COST Approximate cost of basic system $350,000 f.o.b. factory. PERSONNEL REQUIREMENTS Daily Operation No. of Eng. One - 8 hour shift 2 Two - 8 hour shifts 3 Three - 8 hour shifts 4 The number of engineers specified above are based on a 5-day working week and allow for time off due to annual vacations, etc. RELIABILITY AND OPERATING EXPERIENCE Date first unit passed acceptance test 12 Jul 54 Average error free running period 2 hours Operating ratio 0.90 Good time 974 hours Attempted to run 1084 hours No. of separate cabinets(excluding power and air cond.) 2 The above figures are based on 41 weeks of operation since 12 July 1954. ADDITIONAL FEATURES AND REMARKS Organizations operating this system include: Royal Dutch Shell, Amsterdam, Holland Armaments Research Establishment, Fort Halstead Kent AWBE, Aldermaston, Berks. Seven B-lines are provided to facilitate instruc- tion, modification and counting operations. Each B-line has a 20 bit capacity.

FERRANTI MARK-IIFERRANTI MARK-II Ferranti, Ltd Ferranti Electric Mark II MANUFACTURER Ferranti, Ltd. Ferranti Electric, Inc. 30 Rockefeller Plaza New York 20, New York GENERAL SYSTEM Application Scientific calculation Timing Synchronous Operation Sequential NUMERICAL SYSTEM Internal number system Binary Binary digits per word 10 or 40 Binary digits per instruction 20 Total no. of instructions used 64 Arithmetic system Floating-point and Fixed-point. Instruction type One-address code Number range -1 x 2^{+511}<= x <= -1 x 2^{-512}+1 x 2^{-512}< x < +1 x 2^{+511}10 bits = 1 short word 2 short words = 1 instruction 4 short words = 1 long word Any address part of instruction can be modified by any of seven 10-bit registers. ARITHMETIC UNIT Add time(including storage access) 180 microsec 40 bit floating-point 60 microsec 10 bit fixed-point Multiply time(excluding storage access) 300 microsec 40 bit floating-point Construction Vacuum-tubes, Condenser-diodes, Magnetic wheel, Magnetic cores Basic pulse repetition rate 1 megacycle/sec Arithmetic Mode Serial Seven 10 bit modifying registers available to modify address of any instruction. STORAGE Microsec Media Words Access Magnetic Cores 4096 - 10 bit 10 Magnetic Wheel 60,000 - 10 bit 8,000 Electromagnetic Delay Line 14-10 bit 10 Serial computing is performed at 1 megacycle/sec Parallel Magnetic Core Storage at 1000 kilocycle/sec 10 channel. INPUT Media Speed Paper Tape 1000 bits/sec OUTPUT Media Speed Teleprinter 5 char/sec Punch 50 char/sec CHECKING FEATURES Fixed Parity check on core and magnetic wheel storage. PHYSICAL FACTORS Power consumption, Computer 30 K.W. Space occupied, Computer 216 cu ft 36 sq ft Total weight, Computer 2500 lbs NUMBER OF CIRCUIT ELEMENTS Tubes 1500 Tube types 2 Crystal diodes 3000 MANUFACTURING RECORD Number produced 1 Number on order 3 Delivery time 12 months Only a prototype of this machine is working. RELIABILITY AND OPERATING EXPERIENCE Computer not yet operating.

FLACFLAC Florida Automatic Computer MANUFACTURER U.S. Air Force, Patrick Air Force Base, Fla. OPERATING AGENCY Data Reduction Group, RCA GENERAL SYSTEM Application Missile Data Reduction Timing Synchronous Operation Sequential Some of the USAF personnel involved in the construction of FLAC are presently with Soroban Engineering, Inc. Melbourne, Florida. NUMERICAL SYSTEM Internal number system Binary Binary digits per word 44 plus sign Binary digits per instruction 44 plus sign Instructions per word 1 Total no. of instructions used 19 Arithmetic system Fixed-point Instruction type Three-address code Number range All numbers scaled to less than 1 in absolute value. B-box included, address may be modified by B-box or instruction counter. ARITHMETIC UNIT Add time(including storage access) 850 microsec Multiply time ( " " " ) 3300 microsec Divide time ( " " ) 3300 microsec Construction Vacuum-tube and diode gating Number of rapid access word registers 1 Basic pulse repetition rate 1 megacycle/sec Arithmetic Mode Serial Above times are average. STORAGE Microsec Media Words Access Mercury Delay Line 512 182 Magnetic Tape 200,000 Magnetic tape speed is 250 words/sec; 45 digits/word. A new 4096 core storage will be in operation in 1956, with an access time of one word time. INPUT Media Speed Paper Tape (Flexowriter) 1 word/sec Magnetic Wire 40 words/sec Magnetic Tape(Raytheon) 250 words/sec Paper Tape 150 char/sec OUTPUT Media Speed Paper Tape (Flexowriter) 1 word/sec Magnetic Wire 20 words/sec Paper Tape 180 char/sec NUMBER OF CIRCUIT ELEMENTS Tubes 1050 Tube types 5 Crystal diodes 18,000 Computer proper uses only 420 6AN5 tubes and 15,000 diodes. CHECKING FEATURES Fixed Odd-even check provided for storage and Magnetic media Optional Overflow on addition, subtraction and division. PHYSICAL FACTORS Power consumption, Computer 7.5 K.W. Space occupied, Computer 455 cu ft 65 sq ft Power consumption, Air Cond. 7.5 K.W. Space occupied, Air Cond. 52 cu ft 18 sq ft Total weight 1000 lbs Capacity 5 tons MANUFACTURING RECORD Number produced 1 Number in current operation 1 Delivery tine is 12 months from receipt of order at Soroban Engineering, Incorporated, Melbourne, Florida COST Approximate cost of basic system $500,000 Cost is to USAF, PAFB, including development, for placing in service in Sept. 1953. Soroban quotes $388,000.00 for basic system `with $6,500.00 for each Computeriter and $430 f or each input keyboard. Wire drives and con- version equipments prices are dependent upon com- plexity of requirements. Price includes delivery installation, maintenance, supervision and instruc- tion for one year at installation site. PERSONNEL REQUIREMENTS The system is operated for two 8-hour shifts and requires an engineer or technician and one operator. RELIABILITY AND OPERATING EXPEPENCE Date unit passed acceptance test Sept. 19513 Operating ratio 0.90 No. of different kinds of plug-in units 7 No. of separate cabinets(excluding power and air cond.) 6 ADDITIONAL FEATURES AND REMARKS System makes use of two counters, to which addresses may be relative, and has a built in automatic decimal to binary and binary to decimal conversion. Speed of conversion operation is 500 words/sec. Computer resembles SEAC. Soroban Engineering reports computer is assembled from seven basic packages, containing 800 packages, housed in relay racks, insertion of short words, automatic truncation, automatic zero suppression, automatic scaling, printed format control.

HALLER RAYMOND AND BROWNHALLER RAYMOND AND BROWN AN/UJQ-2(xA-l) MANUFACTURER Haller, Raymond and Brown, Inc. State College, Penna. OPERATING AGENCY Haller, Raymond and Brown GENERAL SYSTEM Application Simultaneous Linear Algebraic Equations Timing Asynchronous Operation Sequential NUMERICAL SYSTEM Internal number system Binary Binary digits per word 20 Binary digits per instruction 4 Instructions per word 1 Total no. of instructions decoded 16 Total no. of instructions used 12 Arithmetic system Fixed-point Instruction type One-address Number range 2^{19}to 2^{-19}ARITHMETIC UNIT Add time(excludlng storage access) 200 microsec Multiply time (" " ") 12,000 microsec Divide time (" " ") 12,000 microsec Construction Vacuum-tubes Number of rapid access word register 3 Basic pulse repetition rate 3.5 Kilocycles/sec for mult. and div. 125 Kilocycles/sec for drum read and write. Arithmetic mode Parallel. STORAGE Microsec Media Words Access Magnetic Drum 1200 17,000 Twenty-five digits per drum word INPUT Media Speed Magnetic Tape 20 words/sec Each word consists of a coefficient, an order, and a drum address. OUTPUT Media Speed Berkeley Digital Printer 1 word/sec Max NUMBER OF CIRCUIT ELEMENTS Tubes Approximately 1600 Two major tube types Four very minor tube types CHECKING FEATURES Fixed Computation performed twice, with compare. PHYSICAL FACTORS Power consumption, Computer 5.5 K,W. Space occupied, Computer 120 cu ft 20 sq ft Total weight, Computer Less than 1000 lbs. MANUFACTURING RECORD Number produced 1 Number in current operation 1 PERSONNEL REQUIREMENTS Daily Operation Engr. Oper. or Tech. One 8-hour shift 1 1

HUGHES AAC MOD-IIIHUGHES AAC MOD-III Advanced Airborne Computer Mod III MANUFACTURER Hughes Aircraft Company Culver City, California OPERATING AGENCY Hughes Aircraft Company GENERAL SYSTEM Application Control of airborne vehicle. In the specific application for which the computer was built, it performs navigation, flight control, and weapons control, receiving target and flight data as inputs and generating flight and weapons control signals as outputs. Timing Synchronous with magnetic drum Operation Sequential NUMERICAL SYSTEM Internal number system Binary Binary digits per word 17 Binary digits per instruction 17 Binary digits per instruction not decoded 2 Instructions per word 1 Arithmetic system Fixed-point Instruction type Modified two-address Number range 1-2^{-16}> n > -1+2^{-16}ARITHMETIC UNIT Add time(excluding storage access) 200 microsec Multiply time ( " " ") 1700 microsec Divide time ( " " ") 1700 microsec Construction Vacuum-tubes Number of rapid access word registers 3 Basic pulse repetition rate 162 kilocycles/sec Arithmetic Mode Serial STORAGE Microsec Media Words Access Magnetic Drum 1984 3750 Average Magnetic Drum 8 400 Average Total capacity is 37,648 binary digits. All programs are coded for minimal latency. INPUT Media Speed Analog D.C. Voltage 200 microsec 0-lOOV D.C. Other analog inputs are available. This is used as a control computer with analog inputs and outputs; however, paper tape is used as an additional input medium. OUTPUT Media Speed Analog D.C. Voltage 0-lOOV D.C. Other analog outputs are available. Magnetic tape ultimately feeding a Flexowriter is used as an auxiliary output. NUMBER OF CIRCUIT ELEMENTS Tubes 481 Crystal diodes 33614. PHYSICAL FACTORS Power consumption, Computer 1.5 K.W. Space occupied, Computer 5 cu ft The arithmetic and control unit of the Computer occupies roughly 0.6 cubic feet and weighs 20 lbs. MANUFACTURING RECORD The advanced general-purpose airborne digital computer was developed for the Air Force for automatic control use in high speed aircraft. RELIABILITY AND OPERATING EXPERIENCE Ratio of good time to unscheduled down time is approximately 9. The computer is part of a complete control system. The characteristics of the computer is determined by the characteristics required by the system in which it is to be used. The flip-flops and diode matrices are mounted on individual plug- in wafers and standardized as much as possible so that the bulk of the computer is a multiplicity of a few basic components. Etched circuits and subminiature tubes are used throughout.