GB1107029A - Magnetic film store - Google Patents

Abstract

1,107,029. Magnetic storage apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. 3 Dec., 1965 [30 Dec., 1964], No. 51342/65. Heading H3B. [Also in Division H1] A magnetic store comprises two separated magnetic films, one superposed over the other, a non-magnetic conductive circuit interposed between the two films, and a sense conductor passing in succession through a pair of registering apertures formed one in each film. Each storage cell, Fig. 1, and Fig. 2 (not shown), comprises a substrate 12, a first conductive layer 16, a first strip of magnetic material 18, a second electrically conductive layer 20 acting as a word drive line and a second magnetic strip 22, the strips being in the form of strip portions between which there is disposed a circular portion having a diameter greater than the width forming a toroid about an aperture 30. In order to write information into the store a positive word pulse is applied to the word line 20 from a driver 32 to produce a magnetic field in the first and second magnetic strips 18, 22 perpendicular to the direction of flow of word current and a positive or negative bit current, Fig. 3 (not shown), depending on the value of bit to be stored, is passed through the bit/sense line 36 extending through the aligned apertures 30 of the substrate and strips. This latter current produces a magnetic field circumferentially in a clockwise or counterclockwise direction about the apertures in the magnetic strips depending on the bit stored. In a reading operation a word pulse current is applied to the word strip 20 which induces a positive or negative voltage in the bit/sense line 36 depending on whether a 1 or 0 is stored, the value of the word pulse being such as not to cause irreversible flux changes and destruction of the stored information. A plurality of the above cells may be employed in a matrix, Fig. 4. In an alternative arrangement of the strips, the strips may have a uniform width with apertures disposed therein along the length thereof. In order to reduce stray interbit coupling the magnetic material between the circular portions of the cells may be reduced or eliminated.