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32-543: IBM's electronic (vacuum tube) calculators could perform multiple calulations, including division. The card-programmed calculators used fields on punched cards not to specify the actual operations to be performed on data, but which "microprogram" hard-coded onto the plugboard of the IBM 604 or 605 calculator machine; a set of cards produced different results when used with different plugboards. The units could be configured to retain up to 10 instructions in memory and perform them in

64-480: A card reader and printer; a summary punch could be attached. Processing was directed by a control panel . The 407 was the central component of many unit record equipment shops which were the mainstay of IBM's business at the time. It could print digits, letters and several special characters in any of 120 print positions, spaced 0.1 inches apart (2.5 mm). IBM stopped marketing the 407 Accounting Machine in 1976. The 407 read punched cards , totaled fields on

96-595: A loop. The original CPC Calculator has the following units interconnected by cables: The CPC-II Calculator has the following units interconnected by cables: From the IBM Archives: The IBM Card-Programmed Electronic Calculator was announced in May 1949 as a versatile general purpose computer designed to perform any predetermined sequence of arithmetical operations coded on standard 80-column punched cards. It

128-470: A plugboard connects these devices to perform a specific function, say reading cards and summing up the numbers punched in a group of columns. A modern comparison would be a field-programmable gate array (FPGA), with the plugboard serving the same purpose as the wiring layer in the FPGA. The earliest machines were hardwired for specific applications. Inspired by telephone switchboards , Otto Schäffler invented

160-399: A relay which would inhibit every third card feed cycle (giving the machine a characteristic "shrink-shrink-thunk" sound). It was possible to insert a folded card between that relay's contacts to " overclock " the slower model to the faster speed. The 407 rented from $ 800 to $ 920 per month ($ 10200 to $ 11800 per month in 2023 dollars), depending on the model. Its print mechanism was used in

192-403: A rotating shaft. One rotation represented a single machine cycle, during which punched cards would advance from one station to the next, a line might be printed, a total might be printed and so on. The cycles were divided into points according to when the rows on a punched card would appear under a read or punch station. On most machines, cards were fed face down, 9-edge (bottom edge) first. Thus

224-427: A side and had a rectangular array of hubs. Plugs at each end of a single-conductor patch cord were inserted into hubs, making a connection between two contacts on the machine when the control panel was placed in the machine, thereby connecting an emitting hub to an accepting or entry hub. For example, in a card duplicator application a card column reading (emitting) hub might be connected to a punch magnet entry hub. It

256-430: A wire depended on when in the cycle it occurred, a simple form of time-division multiplexing . Thus an impulse that occurred during 7-time on a wire connected to the column 26 punch magnet would punch a hole in row 7 of column 26. An impulse on the same wire that occurred at 4-time would punch a 4 in column 26. Impulses timed in this way often came from read brushes that detected holes punched in cards as they passed under

288-436: Is often contained in a flat removable panel that can be inserted into a machine and pressed against an array of contacts. This allows the machine to be quickly switched between different applications. The contacts on the machine are hard wired to the various devices that comprise the machine, such as relays, counters, inputs from each card reader column, outputs to a card punch column or printer position, and so on. The wiring on

320-462: The IBM 602 and IBM 604 , that specified a sequence of operations, were described as being programs . Unit record equipment was typically configured for a specific task using a removable control panel. The electrical connections of the various components in the unit record machine were presented on the panel, and connections between them were determined by the wiring, with the actual connections made when

352-446: The IBM 716 introduced in 1952 with the IBM 701 computer, and the 716 was used with many machines in the IBM 700/7000 series . The 407 itself was adapted as an input/output unit on the IBM 650 . Later, the 407 print mechanism was used in the IBM 1132 line printer , part of the low cost IBM 1130 computer system, introduced in 1965. The IBM World Trade Corporation marketed Computing Accounting Machines (CAM), variations of either

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384-561: The Enigma . The first version of the ENIAC computer was programmed via cabling, switches and plugboards. ENIAC's cabling was later reconfigured to use the existing Function Tables data ROM memory as program ROM memory (the switches and plugboards continued to be used in the reconfigured ENIAC). The IBM 305 RAMAC used a plugboard for all program compare operations and all branch operations. Other plugboards controlled card reading and punching,

416-542: The Type 412 or 418, with or without the Type 941, could be operated independently of the other machines. The Type 605 could be used as a Calculating Punch and the punch unit (Type 527) could be operated as an independent gang punch. Customer deliveries of the CPC began in late 1949, at which time more than 20 had been ordered by government agencies and laboratories and aircraft manufacturers. Nearly 700 CPC systems were delivered during

448-799: The brushes, but such pulses were also emitted by other circuits, such as counter outputs. Zone impulses and digit impulses were both needed for alphanumeric printing. They could both be sent on a single wire, then separated out by relay circuits based on the time within a cycle. The control panel for each machine type presented exit (output) and entry (input) hubs in logical arrangements. In many places, two or more adjacent common hubs, would be connected, allowing more than one wire to be connected to that exit or entry. A few groups of hubs were wired together but not connected to any internal circuits. These bus hubs could be used to connect multiple wires when needed. Small connector blocks called wire splits were also available to join three or four wires together, above

480-471: The card reader, printer, counters and storage units were all driven by a single motor, which also drove an oil pump and a generator that provided 46-volt power for the electrical logic. This included about 900 relays which were mounted on three swing-out gates. The control panel had a matrix of 43 by 52 holes, most of which were assigned. The 407 was available in a model that could read 100 cards per minute, and one reading 150 cards per minute. The former had

512-591: The cards, made simple decisions, printed results, and, with the aid of a summary punch, output results on punched cards that could be input to other processing steps. The operation of the 407 was directed by the use of a removable control panel and a carriage tape . Exit hubs (impulse emitting) on the control panel are wired to entry hubs (impulse accepting) for the task to be done (see Wiring of unit record equipment ). There are hubs for each card column (at both reading stations), print position, counter digit, and so on. Logic tests were also available. Each input card

544-414: The control panel. Several are visible in the photo of an IBM 402 panel. The capabilities and sophistication of unit record machine components evolved over the first half of the 20th century and were often specific to the needs of a particular machine type. The following hub groupings were typical of later IBM machines: A plugboard was used on the famous Enigma machine ; it was not removable. In this case

576-548: The field. One example is the Ferranti Argus computer, used on the Bristol Bloodhound missile, which feature a plugboard programmed by inserting small ferrite rods into slots, in effect creating a read-only core memory by hand. IBM 407 The IBM 407 Accounting Machine , introduced in 1949, was one of a long line of IBM tabulating machines dating back to the days of Herman Hollerith . It had

608-435: The first point in a card cycle would 9-time, the second 8 time and so on to 0-time. The times from 9 to 0 were known as digits. These would be followed by 11 time and 12 time, also known as zones. In a read station, a set of 80 spring wire brushes pressed against the card, one for each column (the 407 read station, constructed without brushes, held the card stationary and could read a card multiple times, each time generating

640-429: The first step rotated each wheel to one of 12 groups of characters based on the digit impulse associated with that print position. Digit impulses included the digits 1 through 9 (in reverse order), the 8-3 and 8-4 combination punches and a group (N) for no digit impulse. One of four characters in each group was then selected based on the zone impulse (0, 11, 12 or none) for that character position. This selection happened at

672-499: The first-half of the 1950s. This computer hardware article is a stub . You can help Misplaced Pages by expanding it . Plugboard A plugboard or control panel (the term used depends on the application area) is an array of jacks or sockets (often called hubs) into which patch cords can be inserted to complete an electrical circuit. Control panels are sometimes used to direct the operation of unit record equipment , cipher machines , and early computers . The array of holes

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704-434: The panel was inserted into the machine and locked in place. Perhaps the closest modern analog is the field-programmable gate array , where a fixed number of logic components are made available and their interconnection wiring is determined by the user. Wiring a unit record control panel required knowledge of the machine's components and their timing constraints. The components of most unit record machines were synchronized to

736-400: The per digit pulses needed were generated using commutators , one for each column. This allowed the card to be read more than once at each station, for greater flexibility. For printing, the 407 used type wheels, an improvement over earlier tabulators that used print bars. The 48-character wheels were stationary until a character impulse was to be printed; the wheel then rotated in two steps.

768-415: The plugboard acted as a "fourth rotor" in the rotor machine 's workings. Plugboard wirings were part of the "day settings" that specified which rotors to insert into which slot, and which plugboard connections to make. In practice the plugboard did improve the security of the cypher being generated, but as it did not change with every keypress, unlike the rotors, its impact was limited. See Cryptanalysis of

800-473: The plugboard in order to easily reprogram tabulators. Applications then could be wired on separate control panels, and inserted into tabulators as needed. Removable control panels came to be used in all unit record machines where the machine's use for different applications required rewiring. IBM removable control panels ranged in size from 6 1/4" by 10 3/4" (for machines such as the IBM 077, IBM 550 , IBM 514 ) to roughly one to two feet (300 to 600 mm) on

832-409: The printer and the console typewriter. Many peripheral devices, e.g. the IBM 711 and 716 , for first and second generation IBM computers, including the IBM 700/7000 series and the IBM 650 , were based on unit record machines and included plugboards. Plugboards remained in use in specialty-purpose computers for some time, acting as a read only memory (ROM) but able to be manually reprogrammed in

864-464: The same impulses as would be generated by an 80 spring wire station). When a hole passed under the brush, the brush would make contact with a conductive surface beneath the card that was connected to an electrical power source and an electrical pulse, an impulse in IBM terminology, would be generated. Each brush was connected to an individual hub on the control panel, from which it could be wired to another hub, as needed. The action caused by an impulse on

896-558: The same time the type wheel was driven against the ribbon. The timing of the zone impulse selection was controlled by a complex set of linkages and electromagnets called the Analyzer, one for each of the 120 print positions. Each type wheel also emitted an impulse (called "echo") for the character actually printed. The control panel could be wired so the echo impulses were accumulated for totals; report totals then reliably reflected what had actually been printed. Mechanical systems including

928-471: Was a relatively simple matter to copy some fields, perhaps to different columns, and ignore other columns by suitable wiring. Tabulator control panels could require dozens of patch cords for some applications. Tabulator functions were implemented with both mechanical and electrical components. Control panels simplified the changing of electrical connections for different applications, but changing most tabulator's use still required mechanical changes. The IBM 407

960-520: Was also capable of selecting and following one of several sequences of instructions as a result of operations already performed, and it could store instructions for self-programmed operation. The Calculator consisted of a Type 605 Electronic Calculating Punch and a Type 412 or 418 Accounting Machine. A Type 941 Auxiliary Storage Unit was available as an optional feature. All units composing the Calculator were interconnected by flexible cables. If desired,

992-458: Was read at two successive reading stations. Thus, for example, fields in a card could be compared with the following card and, should a change be detected, say in invoice number, totals could be printed. Unlike earlier IBM tabulating machines , which had 80 read brushes at each read station, one for each column, the 407 had 960 brushes at each station, one for each possible hole in a punched card. Cards were held in position during each read cycle and

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1024-442: Was the first IBM tabulator that did not require such mechanical changes; all the 407's functions were electrically controlled and were completely specified by the application's control panel and carriage tape. For most machines with control panels, from collators, interpreters, to the IBM 407 , IBM manuals describe the control panel as "directing" or "automatic operation was obtained by...". The control panels of calculators, such as

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