Home | Contents | Help   Raidhelp     Simple Odd/Even Parity This form of simplistic parity provides the ability to detect - but not correct - errors in the data. In odd/even parity an extra byte is added onto each byte of data sent. This parity indicates whether the sum of the data is equivalent to either an odd or even number. If the sum of the received bits does not correspond to the parity bit at the end of the byte, the data is discarded and a request to resend the data is made. Example: The letter "L" is a byte with the bit pattern "01001100". The sum of these eight bits is three which is an odd number. In this case an odd bit - equivalent to an extra "1" is placed at the end of the byte. The resulting bit pattern is therefore: "010011001". If the sum of the eight bit being sent was an even number, a "0" would be placed at the end of the byte. The problem with simple odd/even parity is that it can only detect single bit errors. If two of the bits received were incorrect this form of parity would be unable to distinguish the error. Related topics: RAID Parity Understanding Parity Understanding XOR Calculations     Raidhelp   RAIDhelp© Copyright 1999-2004 Antony Kershaw