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BRL 1961, FADAC, start page 0254


Field Artillery Digital Automatic Computer MANUFACTURER Autonetics Division North American Aviation, Incorporated Photo Photo by U. S. Army APPLICATIONS FADAC -Field Artillery Digital Automatic Computer is a rugged, general purpose, portable computer developed under the sponsorship of Frankford Arsenal. FADAC design is based on the existing requirements for solving gunnery problems of tube artillery, free rockets, and missiles. Extreme versatility also enables solution of field artillery support computations related to surveying, counter battery, fire planning, flash and sound ranging, reduction of meteorological data, and master control and programming for automatic checkout of missile systems. Mechanization of FADAC is based on solution of the differential equations of projectile motion from firing to impact. Necessary input data such as target location, powder temperature, gun location, meteorological data (inserted manually or by tape reader) are entered by means of a simplified keyboard. FADAC training time for experienced fire control personnel is extremely short. When all data are entered, depression of a button initiates computation; gun orders comprising deflection, quadrant elevation, fuze time, and charge are displayed in decimal form. A high-speed automatic logic tester and a component tester are also available with FADAC; these are in addition to the self-checking features within the computer. PROGRAMMING AND NUMERICAL SYSTEM Internal number system Binary Binary digits/word 35 Binary digits/instruction 35 Instructions/word 1 Arithmetic system Fixed point Instruction type 1 plus 1 Address of operand and next instruction
BRL 1961, FADAC, start page 0255
Photo Control Panel of the FADAC ComputerPhoto by U. S. Army The matrix switches (A) allow the operator to enter fire control parameters or select prestored parameters. Depression of one button in the vertical row and one button in the horizontal row selects one of sixty-four locations and identifies one particular problem parameter. The manual keyboard (B) allows the operator to enter problem information for different type fire missions which has not been prestored in the memory. The mechanical tape reader (C) is used for entering the meteorological data which are contained on a punched tape. Final problem solutions are displayed on the 16 Nixie tubes(D). Word format +--------+------+--------+--------------------------+ | 1 | 1 | 2 | 31 | +--------+------+--------+--------------------------+ | Parity | Sign | Spacer | Numerical Absolute Value | +--------+------+--------+--------------------------+ Five 1-word registers for arithmetic and control One 2-word register for output information storag System is straight binary for internal operations with automatic conversions to other codes for input- output. Twos complement notation for negative num- bers is used. ARITHMETIC UNIT Add time 7.8 Microseconds Execution time for each instruction is 7.8 micro- seconds. High speed (2-bits at a time) multiplica- tion, division and shifts. Arithmetic mode Parallel by function Serial by bit Timing Synchronous Pulse repetition rate 448,000 pulses/sec Operation Sequential STORAGE Media Words Magnetic Disc (Main)4,096 Magnetic Disc (Hi-Speed) 32 32 channels of 128 words each, of which 24 channels are designated as permanent storage and 8 channels as working storage. The 32 words are two word high speed loops. Disc rotates at 6,000 rev/min and its storage is nonvolatile.
BRL 1961, FADAC, start page 0256
INPUT Media Speed Keyboard Manual Paper Tape Mechanical Paper Tape 700 char/sec Gunnery Off Console Manual Another FADAC Magnetic Tape Other FIELData Equipment Teletype Five or eight channel paper tape, 5-level teletype or FIELData code. Automatic conversion to machine language provided. Maximum inputrate is 4,250 char sec. OUTPUT Media Visual Display (Nixie) Signal Level (Console) Another FADAC Battery Display Printer Magnetic Tape FIELData Equipment Teletype Equipment System provides information in either 5-level teletype, 2- wire teletype, or FIELData codes. Maximum output rate is approximately 4,250 characters per second. CIRCUIT ELEMENTS OF ENTIRE SYSTEM Transistorized CHECKING FEATURES Parity check on FIELD at a information transfer. Verify feature on input in program-full mode. Marginal test provision for preventive maintenance. Voltage transient and temperature warning indicators. POWER, SPACE, WEIGHT, AND SITE PREPARATION Power, computer 0.700 Kw Three phase, 4-wire, 400 cycles/sec, 120208 volts. Automatic power loss interlocks and phase reversing features are provided. Volume, computer 5 cu ft Weight, computer 175 lbs System operates from -25oF to 125oF (external ambient at sea level). Capable of operating to -40oF with kit. Automatic temperature protection is provided. ADDITIONAL FEATURES AND REMARKS Additional features include logic provision for expandable memory; standardized etched boards utilized for reduction of logistics problems; ruggedized for field use; system design provides auxiliary equipment on an integrated basis for computer memory loading, automatic computer testing, and subassembly maintenance, and peripheral equipment for additional operator control in program checkout. [ page 357 is blank ]
BRL 1961, FOSDIC, start page 0258


Film Optical Sensing Device for Input to Computers MANUFACTURER U. S. Department of Commerce National Bureau of Standards
Photo Photo by the Bureau of the Census APPLICATIONS System is utilized for the reading and conversion of microfilm copies of Decennial Census Schedules (position marked documents) to magnetic tape for computer input. PROGRAMMING AND NUMERICAL SYSTEM Internal number systemBinary coded decimal Number bin cod dec dig/wordVariable Number instructions decoded 45 Arithmetic system None Instruction type Plugboard FOSDIC converts coded marks on microfilmed documents to information on magnetic tape in the following manner: (1) A flying spot scanner tube is programmed to make several calibration tests on each document measuring dark level, light level, tilt, horizontal and vertical reduction ratios. (2) The beam is then programmed using major and minor jump instructions (coordinate increases or decreases) to locate 1/4" black reference marks called "indexes". (3) From a given index, program steps then positions the beam over each possible marking position, measuring light output and interpreting the result as either an "answer" or "no answer". (4) The most dominant (darkest) of the answers is held in memory until all positions for a given question have been scanned. This answer (as coded by the program plugboard) is written on magnetic tape. (5) Magnetic tape format is UNIVAC compatible, 100 pulses/inch, 720 character blocks in fixed format. The FOSDIC internal word and frame lengths are variable, however, and many formats (number of frames per block, number of digits per word) are possible under program control. STORAGE Temporary fast storage by means of flip-flops.
BRL 1961, FOSDIC, start page 0259
Photo Photo by the Bureau of the Census INPUT Medium Speed Microfilm 2 - 4 frames/sec Flying spot tube scanning OUTPUT Medium Speed Magnetic tape 2,376 char/sec Speed depends on amount of document information. CIRCUIT ELEMENTS OF ENTIRE SYSTEM Type Quantity Tubes 1,200 Diodes 2,000 Transistors 3,000 FOSDIC consists of a Scan Unit constructed of vacuum tubes, cathode ray tubes, photocells, magnetron beam- switching tubes, and conventional pointto-point wiring; and a Program Control Unit constructed of solid-state components, transistors, diodes, etc., mounted on printed circuit boards. CHECKING FEATURES Numerous scan, magnetic tape and program interlocks sprocket and parity checking on magnetic tape output are utilized. POWER, SPACE, WEIGHT, AND SITE PREPARATION Power, computer 5 Kw 5 KVA 1.0 pf Volume, computer 3,000 cu ft Area, computer 300 sq ft Room size, computer20 x 20 x 10 ft Floor loading, computer140 lbs/sq ft Figures are for each system. Air conditioner is part of integrated system. Site preparation included alteration of area from previously subdivided sections onto single enclosed area; provision of air ducts and space air conditioning equipment; alteration of lighting fixtures; provision of power consuits and outlets; fire wall construction.
BRL 1961, FOSDIC, start page 0260
PRODUCTION RECORD Number produced to date 5 Number in current operation 4 Number in current production 4 FOSDICs currently manufactured by Bureau of the Census personnel for their own production needs. COST, PRICE AND RENTAL RATES Total cost for development and construction of 5 FOSDIC systems with 1 magnetic tape unit each $633,000 PERSONNEL REQUIREMENTS Three 8-Hour Shifts Supervisors 3 Analysts Programers } 3 Coders Engineers 2 Technicians 10 In-Output Oper 12 Operation tends toward open shop. Methods of training used Training branch conducts formal classroom sessions for programmers, operators (followed by on-the-job training executive orientation, brush-up seminars. Classroom and on- the-job training also conducted for engineers and technicians. Programmers are customer employees. RELIABILITY, OPERATING EXPERIENCE, AND TIME AVAILABILITY Date this system passed Acceptance Test Sep 59-Mar 60 Time is not available for rent to outside organizations. Each system is operated an average of about 100 hours per week, excluding scheduled maintenance. ADDITIONAL FEATURES AND REMARKS Prior to the invention of FOSDIC the bulk input medium has generally been punch cards but a few figures showing our experience in 1950 points out certain of their limitations. At that time we used a force of nearly 2000 key punch operators at the peak of operations, and over 14 months was needed at a cost of almost six million dollars just to record the enumerated population and housing data on cards. These facts led Census back to the Bureau of Standards for additional study and review of the input problem. Out of this interchange grew FOSDIC I. The name is an abbreviation of Film Optical Sensing Device for Input to Computers. Designed and built for Census by the Bureau of Standards, it promised a breakthrough in the input problem area. The principle was based on field documents being position coded (by checking the proper box, microfilming the documents, and scanning the microfilm with an electronic beam. The detected position codes are written on the magnetic tape which is our computer input medium. This early model FOSDIC served Census well. Several special tasks were successfully processed through its use. Its chief contribution, however, was in showing the way to a more versatile, faster, less restrictive system. Subsequently, Bureau of Standards and Census engineers collaborated on a successor, FOSDIC III. In the meantime, the Bureau of Standards had produced FOSDIC II which is used by the Weather Bureau to do a high-speed search on large punch card files which have been reduced to microfilm. FOSDIC III captured our imagination. It features a completely programmable scan, permits tremendous flexibility in schedule and questionnaire design, and has such features as automatic calibration on each microfilm frame measuring dark level, light level; compensation for tilt or non-parallelism due to photography or printing; compensation for size variation in the filming reduction process; blank line elimination (conditional jumps over partiallyfilled out documents); and dominant mark, an ability to choose the darkest of several competing marks, thus eliminating the problem of erasures. It is plugboard programmed and has about 45 instructions and program loops. Iterations are possible as with internally-stored program computers. Documents are limited only to be 20" x 14" or less, and their microfilm counterparts will be translated to programmer-chosen codes on magnetic tape at about 100 frames or documents per minute. This works out to an average character rate of about 19,000 24,000 characters per minute. A tough rate for a key punch operator to match. The 1960 Decennial Census The equipment utilized 5 FOSDIC systems consists of: 4 Univac Scientific 1105 Computers with 18 tape units each, 2 Univac I Computers with 10 tape units each, 2 600 lines per minute High-Speed Printers, equipped with Block Buffers, 1 Card-to-Magnetic Tape Converter, and a host of miscellaneous auxiliary equipment of a minor nature. Adopted procedures for magnetic tape handling include fire wall construction; metallic containers for magnetic tape, fire fighting organization and training, control system for defective and damaged tapes, and standardization of tape reel lengths and markings. INSTALLATIONS Bureau of the Census Washington, D. C.

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