Patent GB-886934-A (GB)
Title: Magnetic core switching devices
IPC: G11C19/06
Filed: 1958-12-29
Abstract: 886,934. Magnetic core storage devices. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 29, 1958 [Dec. 30, 1957], No. 41907/58. Class 38 (2). [Also in Groups XIX and XXXIX] A multi-path core of rectangular loop material 10 (Fig. 1), has inner and outer flux paths linked respectively by an A.C. control winding 34 and a saturating D.C. control winding 36 so that with successive half-cycles of the control current in 34 the flux produced thereby switches from the direction shown in Fig. 1 to that shown in Fig. 3A. This produces an output in a winding on leg 16 or leg 18 by switching either path 16 or, if input winding X is simultaneously pulsed by an input signal which prevents switching of 16, by switching of path 18. A succeeding oppositely-directed halfcycle from clock pulse source 32 then switches back whichever of paths 16 and 18 was previously switched and thus produces a pulse in either output winding T1 or output winding T2. The pulse produced in winding T1 or T2 by the initial clock pulse may be suppressed by a diode or a saturable reactor in series therewith. Spurious pulses in input winding X may be similarly suppressed. Path 14 is prevented from switching by the D.C. winding 36. The core device may have two information input windings on one storage leg (Fig. 5, not shown) to obtain the logical functions " NEITHER NOR " and " INCLUSIVE OR." It may also have any number " n " of storage legs 56, 58, 60 (Fig. 6), provided that the cross-sectional area of the D.C. saturated control leg or legs 54 corresponds approximately to the crosssectional area of n-1 storage legs. The flux switching due to the clock pulses can then be made to take place in different storage legs by preventing switching, in the storage legs forming shorter magnetic paths with the control legs, using coincident information pulses in windings thereon. Fig. 8 shows an arrangement with information inputs P and Q, and an output winding on each storage leg, which obtains the functions " NOT P," " NOT IF THEN," " AND," " NOT BOTH," " IF THEN " and "P." Other functions are obtained by an arrangement (Fig. 9, not shown), in which one information input winding links two of three or four storage legs. Shift register.-Fig. 4 shows three multipath cores 12, 12a and 12b arranged to form a shift register. The coincidence of an input in winding X with an initial clock pulse produces switching in leg 18. Reverse switching of this leg by the succeeding reverse clock pulse then produces a voltage in winding T2 which is applied to winding Xa through diode D so that flux switching in leg 16a is inhibited and switching takes place instead in leg 18a. Reverse switching of leg 18a then results in switching of leg 18b of core 12b. The combination of battery 46 and diode D allows only full outputs to be transferred as described in Specification 748,558. If alternate windings 34, 34a are connected in the same sense to control source 32, a transfer circuit, as described in Specification 841,619 may be connected with output windings T2, T2a and T2b. Specifications 845,431, 854,447 and 875,358 also are referred to.