Home | Contents | Help   Raidhelp     Simple XOR Parity XOR (exclusive "or") is a method of calculating parity. Whereas the simple parity example sums all eight bits in a byte to determine a single odd or even outcome, XOR compares bits and generates a more complex parity value. The advantage of XOR parity is that it allows error detection and correction. However, this comes at a price. XOR parity requires calculations that are more intensive and would seriously affect performance if executed on the host system. Calculations would have to be performed on every single byte transferred, which would be an enormous overhead. As an alternative, XOR calculations can be performed at the disk drive level by utilising an embedded or built-in microprocessor to perform parity calculations in addition to I/O optimisation, data buffering and disk head management. XOR calculation is not a new capability from drive manufacturers. It has been available for several years. Related topics: Understanding Parity RAID Parity Simple Parity     Raidhelp   RAIDhelp© Copyright 1999-2004 Antony Kershaw