Patent GB-1031896-A (GB)
Title: Nondestructive readout transfluxor memory system
IPC: G11C11/08
Filed: 1963-06-24
Abstract: 1,031,896. Circuits employing magnetic storage elements. SPERRY RAND CORPORATION. June 24, 1963 [July 2, 1962], No. 24962/63. Heading H3B. [Also in Division G4] A transfluxor core used for storing binary information is non-destructively read out by passing a read pulse through the core material. As shown in Fig. 2 a matrix store comprises columns of linked transfluxor cores 10a-10c, 10d-10f, each column being formed from a single strip of magnetic material having a substantially rectangular hysteresis loop. The linked transfluxors may include a substrate and may be formed by vacuum deposition, electrodeposition or photo-etching from a permalloy sheet. A core 10 is in the " blocked " state and stores an " 0 " when the whole of the core flux is unidirectional about the larger aperture 6, Fig. 1a, and is in the " unblocked " state and stores a " 1 " when the core flux adjacent the larger aperture is reversed in direction to an outward extent defined by the inner limb of the smaller aperture 8, Fig. 1b. Each core is set to one or other of these states by coincidentlyapplied pulses from sources 38, 40 to selected row and column conductors passing through the smaller apertures, the arrangement shown having a capacity of two three-bit words. To read out a word stored in a column of cores a read pulse 20 is applied through the magnetic material of the linked transfluxors from a source 22, and the cross-fields produced by the pulse cause those cores in the blocked " 0 "state to induce a pair of substantial output pulses 28, 30 in an associated read-out winding 12a-12c without destroying the information stored. As only those cores storing an " O " produce an output, bi-stable flip-flops 42, 44, 46 are provided which are previously set to the " 1 " state, and remain in that state unless switched to " O " by an amplified read-out signal from sense amplifiers 48, 50, 52. A modified matrix store using two cores such as 10g, 10k per bit and capable of storing three two-bit words, is shown in Fig. 5. Writing is effected by pulse. sources 78, 80, and non-destructive read-out by selectively applying pulses to certain of leads 60a, 60b, 62a, 62b. The arrangement enables the position of a particular word stored in the register to be found. A word corresponding to, the word sought is entered in a holding register 70, and digit search drivers 64, 66 for each bit. are set appropriately to T if the bit is " 1 " and C if the bit is " 0," the positions shown corre-. sponding to the word " 01." The two cores for each bit in the matrix store register the true (T) and the complement (C) of the bit stored respectively, thus the word " 01 " is registered. in the right-hand column by cores 1 and 10g being unblocked and 10j, 10t being blocked., Read-out takes place when a digit search gate 68 is opened, the selectively energized leads. 60a-62b passing currents through the linked rows of cores which induce outputs in column read-out windings 72, 74, 76 if an associated core is blocked. Consequently, if no output is obtained in a read-out winding, the associated interrogated cores must all be unblocked and the column of cores therefore stores the required word. This column is indicated by an output from a sense amplifier inverter 82, 84, 86 which is enabled from a search bit gate 88.