A New Minimum Density RAID-6 Code with a Word Size of Eight

RAID-6 storage systems protect k disks of data with twoparity disks so that the system of k+2 disks may toleratethe failure of any two disks. Coding techniques for RAID-6 systems are varied, but an important class of techniquesare those with minimum density, featuring an optimalcombination of encoding, decoding and modificationcomplexity. The word size of a code impacts both how thecode is laid out on each disk's sectors and how large k canbe. Word sizes which are powers of two are especiallyimportant, since they fit precisely into file systemblocks. Minimum density codes exist for many word sizeswith the notable exception of eight. This paper fills thatgap by describing new codes for this important word size.The description includes performancencoding,e properties as well asdetails of the discovery process.