Improvements in or relating to error checking devices

1,041,232. Electric digital data-storage. INTERNATIONAL BUSINESS MACHINES CORPORATION. April 6, 1964 [April 18, 1963], No. 15262/63. Heading G4C. A data memory is addressed by selecting at least one gating device, check information being generated in accordance with which device is selected and being compared with check information stored with the address in the address register. Referring to Fig. 1 (not shown) which shows means for selecting one co-ordinate of a magnetic core matrix store, one of 64 address lines is selected by selecting one of 8 left-hand gates and one of 8 right-hand gates in accordance with corresponding binary-coded addresses in an address register 1. Current passes through one of two transformers 11, 12 depending on whether the address of the selected left-hand gate has an odd or even number of 1's. Transformers 13, 14 are selected similarly with respect to the right-hand gates. The transformers 11 to 14 supply inputs as shown to an exclusive-or gate 16 via latches 31, 33, the output of gate 16 being compared at 35 with a parity bit from register 1.