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Double Error Correction for Low End Memories Disclosure Number: IPCOM000047601D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07

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Schomburg, JF [+details]


Double error correction (DEC) techniques are added to existing memory cards, which contain "single error correct-double error detect" (ECC (error correction code)) circuitry, by the use of off-card inverters and the routing of recomplemented data back to an all-good address in the memory before performing the second stage of the ECC routine. The double complement-retry (DCR) method of correcting two errors (if at least one of them is a "hard" error) requires that the codeword which has two errors be inverted and re-written in memory, then fetched and inverted again before being processed through the ECC circuitry.