Patent GB-913452-A (GB)
Title: Improvements in and relating to memory devices
IPC: G11C11/06
Filed: 1961-05-04
Abstract: 913,452. Circuits employing bi-stable magnetic elements. INTERNATIONAL BUSINESS MACHINES CORPORATION. May 4, 1961 [May 25, 1960], No. 16140/61. Class 40 (9). {Also in Group XIX] A three-dimensional magnetic storage matrix arranged for binary word registration and readout includes facilities for sensing the state of the individual storage cores in a row of a single matrix plane. As shown in Fig. 2, each matrix plane Z comprises rows and columns of storage cores 2 having the usual column, row, inhibit and sense windings X, Y, Z and C, and at least one plane is additionally provided with separate bit read-out windings B, one for each column of cores. To write or read a binary word in the matrix, the X and Y windings appropriate to a certain core position in each plane are coincidently energized, and during the writing phase those planes in which a binary zero is to be registered are disabled by energizing the associated inhibit windings Z. To read the binary digits registered in a row of cores in a particular plane, a selected Y winding in that plane and the inhibit winding Z are pulsed simultaneously, and the state of each core is indicated by the voltages induced in the readout windings B. A three-dimensional store is shown in Figs. 4 to 7 comprising matrix planes Z1, Z2 and Z3. The following facilities are provided :- Word write. The information to be stored is applied from a new information source 73 to bistable units 25<SP>1</SP>-25<SP>111</SP>. At the same time WRITE and WORD leads 63, 69 are energized to open AND gates 41, 43 and 27. Any bistable unit in the zero state then operates a read driver 31 which applies a negative energization to the inhibit winding of the respective matrix plane. The position of the word to be registered in the matrix is determined by X and Y address registers 33<SP>1</SP>, 33<SP>11</SP>, each register applying a signal over a respective AND gate 41<SP>1</SP>-41<SP>111</SP> and 43<SP>1</SP>-43<SP>111</SP> to operate an X and a Y write driver 7, 15. A core in each of the unhibited planes is then switched to the " one " state by coincident half-write positive pulses. Word read. AND gates 45, 47 and 21 are opened by energizing READ, WORD and SAMPLE leads 65, 67, 69. The X and Y address registers determine the position of the word in the matrix to be read, and apply a signal over a respective AND gate 45<SP>1</SP>-45<SP>111</SP> and 47<SP>1</SP>-47<SP>111</SP> to an X and a Y read driver 7, 15. Negative half-read pulses are applied, by the read drivers to a selected core in each matrix plane, and those cores which are switched from " one " to " zero " induce outputs in the associated sense windings C1-C3. These outputs are amplified and applied over AND gates 21<SP>1</SP>-21<SP>111</SP> to set the read-out word in the bistable units 25<SP>1</SP>-25<SP>111</SP>. The registration is not transferred to the bi-stable units and is therefore destroyed if the AND gates 21 are closed due to non-energization of the sample lead 69. Word re-write. As the word transferred from the memory to the bi-stable units is equivalent to a new information registration, the word may be re-written by initiating a new word write operation. Bit read. In this case READ, SAMPLE and BIT leads 65, 67 and 71 are energized to open gates 47, 51 and 61. The row of cores in a given plane to be read is determined by Y and A address registers 33<SP>11</SP>, 33<SP>111</SP>, which apply signals over a respective AND gate 47<SP>1</SP>-47<SP>111</SP> and 61<SP>1</SP>- 61<SP>111</SP> to a Y and an A read driver 15, 31. Negative half-read pulses are supplied by the read drivers to the selected Y winding and inhibit winding A, and the cores in the row are driven to state zero. As a result, output pulses each indicative of the initial state of an interrogated core are induced in respective bit read-out windings B-B<SP>11</SP>, and after amplification pass through AND gates 51<SP>1</SP>-51<SP>111</SP> for registration in the bi-stable units 25<SP>1</SP>-25<SP>111</SP>. If the information read out is not required, the energization of the SAMPLE lead is omitted so that the gates 51 are closed. Bit re-write. The WRITE and BIT leads are energized to open gates 43, 53 and 59. The Y and A address registers are again used to select a row and plane, and respectively energize a Y write driver 15 and an A write driver 31, both of which apply positive half-write pulses to their respective matrix windings. All the cores in the selected row are switched to state one except those which are inhibited by negative signals in the X windings, these windings being energized by the zero outputs of the bi-stable units which are applied over gates 53<SP>1</SP>-53<SP>111</SP> to the X read drivers 7.