Patent GB-777440-A (GB)
Title: Tabulating and calculating machine
IPC: G06F7/52
Filed: 1953-06-22
Abstract: 777,440. Digital electric calculating-apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. June 22, 1953 [June 25,1952], No. 17212/53. Class 106 (1). A record card controlled accounting-machine comprises electromechanical counters, an electronic calculating unit including electronic counters,. card feed mechanism comprising at least three successive sensing stations all operable without interruption in the feeding of cards, and means for reading data additively or subtractively into the electromechanical or the electronic counters from one or more of said are the same irrespective of whether that counter is electronic or electromechanical. The machine described is basically a tabulator using electromechanical counters of the type described in Specification 485,103, where a movable contact is clutched to a rotating shaft for a differential period of a mechanical cycle and a printer of known type, and is modified by the addition of electronic counters and control means which enable multiplication and division to be performed. A card punch may be connected to the machine to enable a summary card to be produced. The machine is organized as a number of essentially distinct units which can be interconnected in a variety of ways by means of a plugboard. Three rows of sensing brushes are provided enabling three cards to be sensed simultaneously. A relay comparing unit enables a change in a group number to be detected. The comparer can be plugged to compare independently up to four different fields on two cards being sensed; in this way a change in a particular field can initiate an operation associated with that field. For example a change in the group number in a first field may cause a sub-total to be printed whereas a change in a second field may cause a grand total to be printed. Every time a change is detected in a group number, irrespective of the field and in addition to the operations associated with that field, card feeding is stopped and a ten-position electromechanical distributer becomes operative applying a voltage sequentially to a set of ten hubs and advancing from one hub to the next after each mechanical cycle. These hubs are plugged to control operations common to all fields, for example printing. The machine also contains many other hubs which provide voltages at any desired times; these hubs together with the ten-position distributer hubs and hubs associated with the comparison circuits, are collectively referred to as a general operation programme unit. Electromechanical relays are used as auxiliary number storage devices (four relays per decimal digit on a " 1, 2, 4, 8 " basis). The electromechanical and electronic counters have in common the feature that the plug connections that have to be made when they are to operate depends only upon the particular operation. Operations involving the electronic portion of the machine are described in the following order: (1) Electronic timing; (2) Primary chain; (3) Seconreading or sensing devices, the machine being such that in respect of any particular counter the control settings for arithmetic operations dary chain; (4) Zero reset of triggers; (5) Electronic Programme unit; (6) Electronic accumulators-general; (7) Read-in to electronic accumulators from stores which can be " scanned " at electronic speeds; (8) Multiplication; (9) Division; (10) Read-out of electronic accumulators; (11) Read-in to electronic accumulator direct from brushes. (1) Electronic timing. Electronic timing is governed primarily by a multivibrator T1, Fig. 2j, which generates clock pulses occurring at successive intervals of time called " cycle points." Eighteen cycle points, Fig. 8, numbered 9, 8, 7, ... 2, 1, 0, 11, 12, 13, ... 17, 18 form a " primary cycle " and ten primary cycles constitute a " secondary cycle." The times at which the leading and trailing edges of a clock pulse occur are referred to as " A " and " B " times respectively enabling instants of time within a cycle point to be specified. Thus a particular time is specified by the number of the primary cycle, the type of " edge and the number of the cycle point. For example " 3B14 time " means the instant at which the trailing edge of the clock pulse in cycle point 14 in the third primary cycle. When the particular primary cycle is unimportant, its representative number is omitted. Thus " A5 time " means the instant at which the leading edge of the clock pulse in cycle point 5 occurs. (2) Primary Chain. The primary chain performs cycles of operation each lasting for one primary cycle, i.e. 18 cycle points, and produces various control voltages for carry-over and other operations. Initially all triggers such as B1, Fig. 2j (shown in detail in Figs. 3 and 3a) are conducting on their sides marked with a cross, and each trigger is so constructed that its state is not altered by a positive pulse applied to either of its control grids. Also initially, with trigger B1 conducting on its right-hand side the multivibrator T1 is in stable equilibrium, appearing like a mono-stable trigger. Operation of the primary chain is initiated by relay E6 which when energized (by the programme unit) closes its contact E6-a, changing the state of trigger B1 and starting the multivibrator T 1 oscillating. During the first nine cycle points thyratrons 9U-1U are successively fired at times B9, B8, ... B2, B1 (see also Fig. 8) by the combined action of tubes T4 and T5, tube T4 being initially conducting and acting as a gate under the control of a trigger B3 (lead 288) for pulses transmitted from the multivibrator via a triode T2, a trigger B2, a triode T3, and a lead 285. The firing of thyratron 1U, Fig. 2k, at time B1 opens a gate thyratron T6 by raising the potential of its grid G2 which then passes the next position pulse applied to its grid G1 from lead 285 (the positive pulse lasting from BO to B 11 time) to extinguish all the thyratrons 9U-1U by applying a positive pulse to their cathodes. The firing of thyratron 1U also opens a gate tube T10 whose grids are in parallel with thyratron T6, which then changes over trigger B3 at time BO to shut gate tube T4. Pulses transmitted on lead 285 will then not affect the thyratrons 9U-1U. Up to this time, time BO, negative pulses applied from the multivibrator via triode T2, trigger B2 and triode T3 to an arrangement of triggers B4-B8, Fig. 2k, have been ineffective since they have been applied to the non-conducting sides of triggers B4-B8, but at BO time the positive pulse passed by thyratron T6 causes triode T11 to conduct and to change over trigger B14 so that further pulses applied to the arrangement B4-B8 will be effective. These further pulses are counted by the triggers B4-B8 and, inter alia, at time B16 trigger B8 is changed over to cut-off normally conducting triode T9 and at time B18 trigger B8 is re-set causing triode T9 to conduct again and apply a negative pulse to lead 341. This negative pulse at B18 time marks the end of a primary cycle and if relay Calc. is not energized it is applied via contact Calc.-11 to trigger B1, thus stopping the multivibrator after only one primary cycle. During calculations, however, relay Calc. is energized and ten primary cycles counted by a secondary chain are performed before trigger B1 is reset to stop the multivibrator. (3) Secondary chain. This unit, like the primary chain, performs cycles of operation, but differs in that each of its cycles lasts for ten primary cycles. Its basic unit, a " 1, 2, 2, 4 " counter formed by triggers B11-B14, Fig. 2l, receives during each primary cycle nine pulses at cycle points 8, 7, 6, 5, 4, 3, 2, 1, and 0, from an arrangement of tubes T14, T15, T18 and T19, which operates in the following manner. Tube T15 receives pulses direct from the multivibrator, via a lead 276, which it passes to lead 345 providing tube T14 is not conducting. Tube T14 is controlled by trigger B3 and made to conduct at time BO until the end of each primary cycle when trigger B3 is re-set. Tube 15 thus passes to lead 345 ten positive pulses, one in each of cycle points 9, 8, ... 1, 0. Only nine of these are passed by tube T18, however, since its grid G2 is controlled by thyratron 9U which does not fire until B9 time and thus the pulse in cycle point 9 is suppressed. The trigger B 11 of the counter B11-B14 thus receives nine pulses in each primary cycle either direct from tube T18, lead 365, and contact Calc. 12 if the Calc. relay is energized-when the counter advances at times 8A, 7A, ... 1A, OA- or via tube T19 when the Clac. relay is not energized-when the counter advances at times 8B, 7B, ... 1B, 0B. During calculations the counter B11-B14 is reset to the value nine (left-hand sides conducting) and when it passes to the value zero it emits simultaneously two pulses, a negative pulse on lead 360 from trigger B14 and a positive pulse on lead 373 from trigger B12. Thus with the counter initially at nine, and the relay Calc. energized, it will emit pulses at time 1A8, 2A7, 3A6, ... 8A1, 9AO, and will not emit any pulses in the tenth primary cycle. The negative pulses emitted at these times change over via lead 360 the trigger B17 associated with which is a diode 386 which acts as a gate, the potential on its right-hand side, lead 387, only rising when triggers B17 and B8 are both simultaneously conducting on their left-hand sides. This situation only occurs in the tenth primary cycle, however, since in each of the first nine primary cycles trigger B17 is changed over by pulses on lead 360 to conduct on its right-hand side before trigger B8 changes over to its left-hand side which is not until B16 time, but in the tenth primary cycle trigger B17 is not changed over and so at 1OB16 time when B8 changes over a positive pulse is produced on lead 387 which fires a thyratron T26 causing the relay E7 to pick-up. At 10B18 time, when trigger B8 changes back to its normal condition, a negative pulse is produ