Patent GB-884385-A (GB)
Title: Digital information memory system
IPC: G11C7/02
Filed: 1959-09-21
Abstract: 884,385. Magnetic pulse-storage circuits. INTERNATIONAL BUSINESS MACHINE CORPORATION. Sept. 21, 1959 [Dec. 19, 1958], No. 32137/59. Class 40 (9). [Also in Groups XIX and XL (c)] A magnetic information store comprises four ferrite plates 1-4, Fig. 2, each with a matrix of apertures and associated row and column windings and a printed sense winding, the row and column windings being connected in series pairs so as to form a larger matrix to which Y address pulses are selectively applied to the series row windings of either plates 2 and 4 or 1 and 3 over respective conductor groups AY1-AY16, AY17-AY32, and X address pulses are selectively applied to the series column windings of either plates 1 and 2 or 3 and 4 over respective conductor groups AX1- AX16, AX17-AX32, the sense windings 1T3- 4T3 being arranged in series pairs 1T3, 4T3 and 2T3, 3T3 so that spurious induced switching voltages are substantially equal in both pairs. The pairs of sense windings are connected to opposite ends of a transformer winding in a differential amplifier 27 so that the spurious voltages are effectively neutralized and only a true read-out pulse is detected. A selected storage cell in a plate is switched by coincident read or write pulses applied to one of two readwrite address drivers 22, 23 and 25, 26 in both the X and Y address circuits. This energizes transformer switches in one of each of the groups SX1-SX16, SX17-SX32 and SY1- SY16, SY17-SY32, and information registered in X and Y diode matrices 21, 24 enables a pulse to be applied over each energized group to a selected column and selected row conductor AX1-AX32, AY1-AY32. Each transformer switch comprises two primary windings 6, 7 and steering diodes D1, D2. When read-out pulses are applied coincidently to a selected storage cell, the induced pulse in the sense winding is separated from the spurious voltages by the transformer in the differential amplifier 27 and, since the pulse may have either polarity depending on which sense winding pair it appears, a bridge amplifier is used to provide a unidirectional output. Both amplifiers incorporate transistor circuits (see Group XL (c)). A strobe amplifier 29 corrects the pulse to a given amplitude and with prior to its registration in a buffer store 30 having " 1 " and " 0 " outputs. The " 0 " output passes to AND gates 33, 34 which are also energized by a write timing pulse. This circuit prevents causes inhibiting drivers 31, 32 to prevent a re-writing operation in the read-out storage cell by energizing all the sense windings if a stored " 0 " was initially detected. In a modification, Fig. 3 (part), two reading cycles for the plates 1, 4 and 2, 3 respectively may be used, in which case the output from the strobe amplifier 29 is applied to one of two buffer stores 30A, 30B, depending on which terminal 39 or 40 is pulsed during a reading cycle A or B. Selection is effected through AND gates 37, 38. For rewriting, each inhibit driver 31, 32 is connected to a respective buffer store by way of an AND gate 34, 23, the write timing pulse being applied to terminal 85 so that inhibition is selectively effected in the separate pairs of series-connected sense wordings. Specification 861,688 is referred to.