Patent GB-781295-A (GB)
Title: Improvements in calculating machines
IPC: G06F7/52
Filed: 1954-05-26
Abstract: 781,295. Digital electric calculating-apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. May 26, 1954 [June 9, 1953], No. 15519/54. Class 106 (1). A calculating - machine comprises electronic calculating devices, electromechanical storage devices, means for registering numbers in and out of said storage devices, an electromechanical programme device and electronic control means co-operating with said calculating devices, the control means being arranged to act in interspersed cycles between operations of said electromechanical programme device in governing registration of numbers to and from said storage devices and calculating devices. A calculating punch, programmed manually by pre-plugging, is described for performing addition, subtraction, multiplication and division, date being both entered into the machine and issued from the machine by means of punched cards. Electronic timing. Electronic timing is governed primarily by a multivibrator T1, Fig. 3k, 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. 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. 3k (shown in detail in Figs. 5 and 5a) 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 non-stable trigger. Operation of the primary chain is initiated by relay E9 which when energized (by the programme unit) closes its contact E9-a, changing the state of trigger B1 and starting the multivibrator T1 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 date 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. 3L, at time B1 opens a gate thyratron T6, by raising the potential of its grid G2, which then passes the next positive pulse applied to its grid G1 from lead 285 (the positive pulse lasting from BO to B11 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. 3l, 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 cuts off normally conducting triode T11, which then fires T13, which in turn changes over trigger B18 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 a relay 2A is energized it is applied via contact 2A-14 to trigger B1, thus stopping the multivibrator after only one primary cycle. During calculations, however, relay 2A is not energized and ten primary cycles counted by a secondary chain are performed before trigger B1 is reset to stop the multivibrator. 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 B11-1314, 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 435 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 B11 of the counter B11-B14 thus receives nine pulses in each primary cycle either direct from tube T18, lead 365, and contact 2A-16 if the relay 2A is not energized-when the counter advances at times 8A, 7A, ... 1A, OA-or via tube T19 when the relay 2A is energized-when the counter advances at times 8B, 7B, ... 1B, OB. During multiplications and divisions 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 2A de-energized, it will emit pulses at times 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 which is reset at time B18 by trigger B8 and which controls the grid G2 of the tube T22, the other grid of tube T22 being controlled by T9 and going positive at time B16 and negative at time B18. Thus during the first nine primary cycles the grids of tube T22 are never simultaneously positive and therefore tube T22 does not conduct, but during the tenth primary cycle, no negative pulse is transmitted from trigger B14, trigger B17 is not changed over and thus the tube T22 commences conducting at B16 time and ceases conducting at B18 time when triode T9 returns to its normally conducting condition. When tube T22 starts to conduct at 10B 16 time, it cuts-off normally conducting tube T25 and when it ceases to conduct at 1OB18 time, marking the end of a secondary cycle, it causes tube T25 to conduct and apply a negative pulse to trigger B1, thus stopping multivibrator T1, and applies a positive pulse to thyratron T26 which fires and energizes one of relays E1 and E2, thus stepping the programme unit on one or stepping the multiplication and division coordinating chain on one stage. For calculations other than multiplication and division, i.e. for transfers, the counter B11-B14 is re-set to zero and therefore emits no pulse during the first primary cycle. If the transfer is from the card reading brushes (such a transfer being performed by causing the electronic portion of the machine to go through one basic addition cycle, i.e. one primary cycle, as each line of the card is sensed) then the relay 2A will be energized and thyratron T26 will be conducting, for its duration, and at the end of each primary cycle the negative pulse on lead 341 will go via contact 2A-14 and stop the multivibrator. For other transfers relay 2A will not be energized and at the end of the first primary cycle, trigger B17 is not changed over, tube T22 fires as described above, causing the multivibrator to stop and the thyratron T26 to fire. Resetting of triggers. In each trigger excepting triggers B 11, B12, B13, B14, B10 and B16, and the electronic counters, the grid of the triode that is required to be conductive, indicated by " X," when the trigger is re-set, is connected to a lead 243a and the other grid to a wire 243 to which is applied a biasing potential of - 100 v., Fig. 3k. When the electronic section of the machine is not operating, i.e. when the multivibrator is stopped, relays E8, E15 and E21 are not energized, lead 243a, Fig. 3m, is therefore floating and each trigger is conductive on its side marked " X." Immediately prior to the initiation of oscillation of the multivibrator, either relay E8 or E15 is energized, joining wire 243a to wire 243 (since contact A2-d is always closed once the machine is warm) and applying - 100 v. bias to the triodes marked " X." The application of the bias does not alter the state of the triggers which remain conductive on their side marked " X," and at the end of the electronic operation, relay E8, or E15 drops out, isolating lead 243a, and resetting the triggers as required. Triggers B11, B12, B13, B14, B10 and B16, which have to be reset to their sides marked "X" except for multiplication or division operations when they are reset to " X," have their sides marked "X" connected to a lead 361a and their sides " X " connected to a line 361. When no electronic ope