Patent ID: 8086939

Claim:
A method of accessing data on a RAID device capable of recovering a plurality of failures comprising steps of: (1) issuing an access request from a host device to a RAID controller; (2) if the access request is write, then (2a) copying new data into a local memory from the host device; (2b) writing the new data, from the local memory, into a plurality of disk drives and an XOR circuit via an internal bus; (2c) generating a new parity by the XOR circuit and storing in an XOR buffer; (2d) storing the new parity into the local memory; (2e) writing only the new parity, from the local memory, into a plurality of disk drives; (3) if the access request is read, then (3a) copying old data and old parities into the local memory and the XOR circuit from the disk drives via the internal bus; (3b) recovering lost data and storing recovered data into the XOR buffer; (3c) storing the recovered data into the local memory; and (3d) getting the old data and the recovered data from the local memory.