In computing, telecommunication, information theory, and coding theory, an error correction code, sometimes error correcting code, (ECC) is used for controlling errors in data over unreliable or noisy communication channels. The central idea is the sender encodes the message with redundant information in the form of an ECC.

<algorithm> (FEC) A class of methods for controling errors in a one-way communication system. FEC sends extra information along with the data, which can be used by the receiver to check and correct the data. A CPU writing data to RAM is a kind of one-way communication - see error correcting memory and {error checking and correction}. (1996-10-02)

<algorithm, storage> (EDAC, or "error checking and correction", ECC) A collection of methods to detect errors in transmitted or stored data and to correct them. This is done in many ways, all of them involving some form of coding. The simplest form of error detection is a single added {parity bit} or a cyclic redundancy check. Multiple parity bits can not only detect that an error has occurred, but also which bits have been inverted, and should therefore be re-inverted to restore the original data. The more extra bits are added, the greater the chance that multiple errors will be detectable and correctable. Several codes can perform Single Error Correction, Double Error Detection (SECDEC). One of the most commonly used is the Hamming code. At the other technological extreme, cuniform texts from about 1500 B.C. which recorded the dates when Venus was visible, were examined on the basis of contained redundancies (the dates of appearance and disappearance were suplemented by the length of time of visibility) and "the worst data set ever seen" by [Huber, Zurich] was corrected. RAM which includes EDAC circuits is known as {error correcting memory} (ECM). [Wakerly, "Error Detecting Codes", North Holland 1978]. [Hamming, "Coding and Information Theory", 2nd Ed, Prentice Hall 1986]. (1995-03-14)