Patent GB-898023-A (GB)
Title: Improvements in data storage and computing devices
IPC: G06F12/04
Filed: 1958-12-17
Abstract: 898,023. Electrical digital data-storage apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 17, 1958 [Dec. 23, 1957], No. 40738/58. Class 106 (1). Digital data-storage or computing apparatus . is combined with a plurality of programme control devices, only one of which is operative at a time, said apparatus comprising a ring circuit with stages selectively connected to the programme control devices, the ring circuit advancing from a stage connected to an operative programme control device through succeeding stages until it reaches a stage connected to another programme control device, at which point advance of the ring circuit is stopped and another programme control device is rendered operative. General arrangement. Programme control devices P1, P2, P3 ... are arranged as stages of a ring, the several stages being connected by cords so that the devices may be operative in any desired sequence or according to the results of computations effected by the associated apparatus. The programme devices are connected to rings A and B which control fields in a conventional core-storage device and when a programme device, say P1, is operative the rings advance step-by-step within the limits defined by that device P1. Data addressed by rings A and B are read out in interlaced manner to an adder, a complementing circuit, or back into storage. Data addressed by ring A may be transferred to storage positions addressed by ring B, or data may be addressed by both rings and fed through the complementing circuit to original positions. When a ring advances to a stage connected to another programme control device, say P 2 , a signal is emitted to stop advance of the ring circuit and activate a predetermined programme control device. Pulse generator. A ring counter of known type applies pulses to lines 100-103, Fig. 2j, with the time relationship shown in Fig. 3. The positive pulses on line103 are referred to subsequently as A pulses and the related time as A time, on line 101 as B pulses and B time. Registers and rings. Magnetic core memories M1-M5, Fig. 2h, with the individual stores arranged as in Fig. 13, are of known type. Each memory can register all the information on an 80-column record card. Each location has seven binary elements 1, 2, 4, 8, A, B, C. Energization of element A denotes that the quantity is negative. Element C is energized whenever the number of other elements energized is odd. Access to the stores is had under the control of scanning chains A and B. Ring A comprises a units chain 1U-10U, Figs. 2c, 2d, and a tens chain 0D-7D, Fig. 2b, and can be stepped, in the embodiment described, in the order 80-71, 70-61, and so on at the reception of an A pulse. Ring B comprises chains 11U-20U, Figs. 2c, 2d, and tens chain 10D-17D, Fig. 2b, and can respond to B pulses. General operational principles. As described a factor a in field A is to be added to factor b in field B and the sum b<SP>1</SP> is to be re-entered into field B. The operation is started by reading out the units digit of a, then the units digit of b and entering the sum in the units place of field B, and so on for each denominational place, each step taking two cycles. Carry involves an extra cycle. General control circuits. Triggers B3 ... B13, Figs. 2f, 2g, have specified control functions and can be switched on or off at the end of each time B. They form a chain but more than one can be operative at the same time. Operation of the triggers is dependent on hub connections with the programme control devices P1, P2, &c., and the results of arithmetical operations. B3 is always switched at the beginning of a programme and reset at the end. Search for the sign. Assuming that the programme initiated by switching of trigger P1, Fig. 2e, controls read-out of a factor contained in a memory field A with the sign stored otherwise than in the lowest denomination then trigger B4 is switched at time A to set ring A through appropriate hub connections to give access to the desired store. At time B trigger B4 is restored and B5 is operated and read-out takes place. If the sign is minus triggers AR and B12 operate. At time B the operated triggers in ring A are restored, B5 restores and B6 is operated. B6 controls the setting of the rings to the lowest orders of the memory fields A and B. If, contrary to the condition mentioned above the sign is stored in the lowest denominational position, which is always the case with the factor in field B, then B7 is triggered and sign read-out is effected while rings A and B remain in set condition. Arithmetical operation. At the end of time B trigger B7 is restored and triggers B8, B9 are operated. B8 controls arithmetical operations and remains operated until they are completed. B9 controls the operations relating to the units digits only. Assuming that the numbers to be added are in locations 72-75 of memory M1 and locations 72-77 of memory M2, then the rings A, B are set at the beginning of these operations respectively to M1, 75 and M2, 77. Unit 328 of the type described in Specification 853,413 interrogates all magnetic cores corresponding to tens digit 5, Fig. 2h, while unit 334 interrogates all cores corresponding to units digits 5. In the location 75 of memory M1, therefore, those cores which are active are switched to the neutral state causing read-out to triggers IR-CR, such read-out being transferred at next time A to triggers 1W-AW, the last of which denotes the sign of the number. At the next B pulse read out of the corresponding digit from the other field is effected in similar manner to set the R triggers. Lines from the R and W triggers are connected to an adder 360, Fig. 2i, of known type which marks one or more lines 361 negative. If carry is necessary trigger B13 operates. At the next A pulse the markings on lines 361 are re-entered into the units digit location of field B and triggers R, W are restored. If the sign of the result is negative the A line of group 361 is also marked. The rings A and B are advanced and the above-described operation is repeated for each denomination. When the last denomination in field A has been sensed trigger B10 is switched and stepping of ring A is blocked. When the last denomination in field B has been sensed triggers B8 and B10 are restored and stepping of ring B is stopped. Trigger B3 switches off to restore the operative programme control device, say P1, and energize the next, say P2. Negative result. If the result is negative the answer at present recorded is in the form of a complement and an extra cycle is necessary to register the true value. A negative result is indicated by trigger B12 being operative. Triggers B11 and B6 are then switched. The rings A and B are both set to scan field B and the arithmetical operation O - a = b<SP>1</SP> is effected, whereby the 10's complement is registered together with reversed sign. Subtracing operation. If subtraction is involved the sign of the number a in field A must be reversed and a switching pulse is applied to trigger B12. In the case of a double negative B12 is restored. If b in field B is also negative then B12 is switched yet again. There are thus two possibilities: (1) if B12 is normal the magnitudes of a and b are added, and (2) if B12 is operated a is subtracted from b. If at the end of the operation B13 is normal then the result is in complementary form and the process described above under the heading " Negative result " is carried out. Automatic change of programme. If the result of any operation is zero, trigger B15, Fig. 2j, is switched to mark hub 368 positive. According to whether the result of an arithmetical operation is positive or negative so trigger B16 marks hub 377 or 376 positive. A change of programme may be effected when the result is zero or according to whether it is positive or negative, hubs 368, 376, 377 being connected to appropriate programme triggers P2, P3 &c. Memory split. The memory may record information directly from a punched card in the manner described in Specification 866,599. The hubs associated with any of the programme triggers P1, P2, &c., may be connected to several different hubs 149, Fig. 4, for permitting access to fields storing different kinds of data The size of the fields can thus be varied. Specification 853,413 also is referred to.