Patent ID: 6978345

Claim:
A rotating data storage disk system comprising: a plurality of concentric tracks defined on a disk; said disk including at least two date storage areas, wherein each area is sized to store a copy of a set of data and the data storage areas are substantially equidistantly spaced from each other and wherein all of the at least two data storage areas are located within plus or minus one track of the same track; a drive mechanism coupled to the disk; an integrated controller that manages data storage operations of the disk system, wherein the integrated controller maintains a first redundant data table in volatile memory, and wherein the first redundant data table comprises information about one or more deferred write commands; and, a remote controller in communication with the drive mechanism for maintaining data coherency between the at least two data storage areas and keeping track of deferred writes to the at least two data storage areas of the disk, wherein the remote controller maintains a second redundant data table in non-volatile memory, wherein the second redundant data table comprises information about one or more deferred write commands.