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In telecommunication, a longitudinal redundancy check (LRC) or horizontal redundancy check is a form of redundancy check that is applied independently to each of a parallel group of bit streams. The data must be divided into transmission blocks, to which the additional check data is added. The term usually applies to a single parity bit per bit stream, calculated independently of all the other bit streams (BIP-8).〔 RFC 935: "Reliable link layer protocols" 〕〔 ("Errors, Error Detection, and Error Control: Data Communications and ComputerNetworks: A Business User's Approach" )〕 although it could also be used to refer to a larger Hamming code. This "extra" LRC word at the end of a block of data is very similar to checksum and CRC. == Optimal Rectangular Code == While simple longitudinal parity can only detect errors, it can be combined with additional error control coding, such as a transverse redundancy check, to correct errors. The transverse redundancy check is stored on a dedicated "parity track". Whenever any single bit error occurs in a transmission block of data, such two dimensional parity checking or "two-coordinate parity checking"〔 () 〕 enables the receiver to use the TRC to detect which byte the error occurred in, and the LRC to detect exactly which track the error occurred in, to discover exactly which bit is in error, and then correct that bit by flipping it.〔 Gary H. Kemmetmueller. ("RAM error correction using two dimensional parity checking" ) 〕〔 Oosterbaan. ("Longitudinal parity" ) 〕〔 ("Errors, Error Detection, and Error Control" ) 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「longitudinal redundancy check」の詳細全文を読む スポンサード リンク
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