Abstract: P-code is one new member of Redundant Array of Inexpensive Disks(RAID) coding family, and its structure,coding method and decoding algorithm were analyzed in this paper. Further more the Binary Distribution Matrix(BDM) was firstly applied in P-code study. Based on this work, the approach of RAIL〕6 extension for tolerating more than three disks failure was concluded. Including P-code, the research of vertical RAIL)6 extension of Maximum Distance Separable (MDS) codes should be a new study direction and a difficult research problem in this domain.

Key words: RAID-6 , P-code, Binary distribution matrix, Coding extension