GB1055262A - Improvements in read-only stores - Google Patents

Abstract

1,055,262. Read-only stores. INTERNATIONAL BUSINESS MACHINES CORPORATION. June 24, 1964, No. 26049 /64. Heading G4A. In a read-only matrix store, one of two pairs of coupling capacitors at the intersection of a pair of drive conductors and a pair of sense conductors is disabled to select the polarity of the voltage appearing across the two sense conductors in response to a voltage applied across the two drive conductors, the two disabled capacitors being adjacent to one another in either the drive or the sense direction of the matrix. The invention is a modification of that in Specification 1,055,261 which is referred to, the adjacency of the two capacitors enabling them to be disabled in a single punching operation. In Fig. 3, a row is read-out by pulsing a terminal 18 for the row, the polarities of the outputs from difference amplifiers 6 representing the bits. The small squares 2 represent non-disabled capacitors. Each sense line S1a S1b, S2a etc. contains the same number of non-disabled capacitors, irrespective of the information stored. The adjacency referred to its achieved despite this by having the sense conductors cross over as shown, this occurring without electrical contact since the relevant parts of the sense conductors are on opposite sides of a board bearing them, internally-plated holes through the board being provided (Fig. 4, not shown). The disadvantage that the pattern required for a given bit reverses in going from one row to the next can be removed by connecting the drive current generator across the two drive conductors and with reversed polarity in alternate rows (Fig. 5, not shown). Actual physical crossing of the sense conductors is not strictly necessary and Figs. 6a, 7a, 7b (not shown) show three alternative arrangements of the printed circuitry on the sense board for eliminating it, the first (only) requiring alternately reversed polarity drive generator (see above). All the above embodiments utilize two printed circuit boards one for the sense conductors and the other for the drive conductors, with half the capacitor electrodes on each board, but the two sides of a single board may be used instead (Fig. 8, not shown).