Patent GB-816345-A (GB)
Title: Improvements in or relating to magnetic core memory device
IPC: G11C5/05
Filed: 1956-06-13
Abstract: 816,345. Electric digital-data-storage apparatus. SPERRY RAND CORPORATION. June 13, 1956 [June 13, 1955], No. 18332/56. Class 106 (1). [Also in Group XXXIX] A magnetic matrix store comprises stacks of trays 21 formed of insulating material each containing ten toroids 33 constructed by wrapping molybdenum permalloy ribbon on ceramic bobbins, the read-out windings 55 and the windings 50 comprising one co-ordinate plane being wound on the individual trays while the other co-ordinate plane windings 60 embrace each of the assembled stacks. The arrangement described consists of eight stacks of trays and is intended for use as a buffer store between an 80 column punched card machine and a magnetic tape store, the twelve positions in each column being associated with twelve trays in each stack. Construction. As shown in Figs. 2, 3 and 6, the toroids 33 are arranged in pockets in the trays and are located by covers 22 fixed by cement, the trays and covers having apertures 37 and slots 39, 41, 42 which accommodate the matrix wiring. Each tray carries a co-ordinate plane winding 50 and a read-out winding 55 arranged in coils embracing pairs of toroids as shown and respectively connected to terminal posts 28b, 28c and 28a, 28d, the read-out coils being arranged .to alternate in direction with respect to the other coils so as to improve the signal-to-noise ratio. The trays are assembled in a stack 11 by through bolts 23, and the 'second co-ordinate windings 60 are threaded through aligned toroids in the assembly and connected individually to a multi-contact plug 15. The eight stacks 11 are secured by screws (not shown) on a shelf 12, Fig. 1, which includes an apertured panel through which multicontact sockets 14 are inserted to provide external connections for the windings 60. The other windings 50 and 55-on the trays are interconnected in series to a terminal board 16 by links 65 and 66. Operation. As shown in Figs. 7 and 8, the toroids associated with each co-ordinate plane winding 50 are normally biased at a point A by current over a diode D1 between terminals +290V. and +230V. When a punched card is fed to the sensing brushes, a row tube V1 is pulsed over counting means (not shown) and since the anode is coupled to +225V. by a diode D2, the bias current reverses and passes from terminal +230V. to +150V. As a result the associated toroids change their magnetic state to point B. The voltage at terminal T1 is also stepped from +230V. to +310V. just as the bushes K are opened by the card. When a perforation is detected, a sensing brush completes a circuit through a co-ordinate plane winding 60 to terminal 230V. and the magnetic state of the toroid at the winding intersection is reversed. Tube V1 subsequently becomes non-conductive when the row of the card passes the brushes and the selected core has a final biased magnetic state represented by point D. Read-out is effected by a reverse current which is applied to windings 60 in turn under the control of column counting means (not shown) and causes cores at point D to change to the magnetic state represented by point A. The circuit includes tubes V2, V3 in a function table for each column winding which are clamped by diodes D6, D7 to +227V. when they conduct so that the reverse current becomes effective over diode D3. Read-out in any row may be inhibited by energizing tube V1 which drives the Data-storing cores from D to C. The reverse current is then insufficient to erase the stored information. According to the Specification the pattern of signals transferred to the tape may be changed by altering the connections to the sockets 14. Specification 793,339 is referred to.