Patent GB-981919-A (GB)
Title: Improvements in or relating to memory systems
IPC: G11C15/06
Filed: 1962-06-26
Abstract: 981,919. Digital data storage; electric calculating apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. June 26, 1962 [June 26, 1961], No. 24451/62. Headings G4A, G4B and G4C. Words can be selected in a memory according to specified characteristics and a selected field of each word added together the sum appearing in a register without the words being removed from the memory. Embodiments described use cryotrons or relays. In the cryotron store of Fig. 4 words are stored in rows of bi-stable circuits 10a to 10c, 12a to 12c . . ., like ordered binary digits forming the columns of the matrix. The state of a circuit and the value of the digit stored therein is represented by current flowing in one limb or the other of a superconductive loop. A mask register is set to determine the field of the words on which a selection is made. An association selection register is set to determine the value of the field on which a selection is made and the sum field selection register is set to determine the field of the selected words to be summed by the counting networks, the result appearing in register 124. The counting networks are as described in Specification 923,770. Indicators 97 to 100 such as lamps are operated when a word is selected. A network 102 counts the number of such words, operating in the same way as networks 120, and places the results in register 106. A detail of Fig. 4 is shown in Fig. 5G. The mask register 108 element 110a if set to 0 cuts off current to the like order association selection register 84 element 86a. If the order shown in Fig. 5G is to be masked current is steered by means not shown into the right-hand conductor of the pair 226a and switch 228 is closed. Gates 242a, 148a, 154a and 156a become resistive and no current appears on conductor 146a which supplies the select register. Assuming mask register set to 1 a similar process involving switch 230 determines whether current in conductor 146a is steered to conductors 46 or 48, representing 0 or 1 respectively. The bit represented by the setting of circuit 86a is compared with the bits stored in the bistable devices 10a, 12a &c. If device 10a for example stores a bit different from the setting of circuit 86a current from a source not shown is steered to line 66 since either gates 10 and 62 or 58 and 64 are resistive. If the bit values are the same either line 50 or 52 carries current depending on the setting of device 10a. To select a word order for inclusion in the field to be summed current is steered to the left hand line of the pair 226a. This leads to the marking of the select line. If the suppress line had been marked gate 172 would be resistive and device 10a would be seen by the counting network as if it were storing 0. Similarly if the word in the first row is not chosen current in line 66 closes gates in the counting network which make it appear that device 10a is storing 0. Fig. 7 shows a multiplier which has as operands two fields of the sum register. If the value of multiplier bit is 1 the values of the multiplicand are gated from circuits 408c to counting networks according to the order of the multiplier bit. A dividing circuit is also mentioned in which the dividend is the contents of the sum register and the divisor the number of selected words taken from the register 126. It is stated to be of conventional construction and no further details are given. A relay circuit is shown in Fig. 8A. To enter a 1 into storage device 440b word write line 463 is energized and switch 462b closed. This energizes both the P coils of solenoid 448b and their combined strength is sufficient to switch the contacts which inter alia cause a hold coil of the solenoid to be energized and by-pass the coils to 0 solenoid 444b. The value in circuit 440b is the same as that in the association select register, as indicated by energization of solenoid 468b or 470b, either contacts 472b and 482b or contacts 476b and 484b will be closed, and current on line 488 will energize solenoid 492. A counting network is also provided in this embodiment and the first level comprises contacts 502b, 504b.