Abstract: The present disclosure pertains to multiple-platter disk drive digital data storage with integrated redundancy operations for improved reliability. Within a single disk drive assembly (300), one or more individual storage platters (304) can be used to store redundant data, enabling recovery of user data in the event that another platter (302) is defective, fails or is otherwise unavailable. “On-the-fly” redundancy operations (FIGS. 6A,6B) can be made transparent to the user or host, and impose no significant speed penalty. A data path switch (26) can reconfigure mappings between logical ports and platter interfaces (210) as needed.

Abstract: A RAID disk drive controller (FIG. 33) implements disk storage operations, including striping and redundancy operations with multiple disk drives connected via respective SATA ports (520). Configurable data path switch logic (460) provides dynamic configuration of two or more attached drives into one or more arrays. Data transfers are synchronized locally by leveraging the SATA port transport layer FIFO (530). Synchronous transfers allow on-the-fly redundancy (XOR) operations (FIG. 36) for improved performance and reduced hardware complexity. XOR accumulator hardware (FIG. 42-FIG. 43) reduces buffer requirements for multiple DMA channels otherwise required for synchronization, and various narrow and wide striping modes are supported.

Abstract: A RAID disk array controller implements a write mask to support partial-stripe updates from a host system without expensive RAM to RAM copying and repeated disk accesses to assemble the updated stripe. New data from the host is transferred into a single buffer and a local processor tracks—by setting bits in the write mask—which segments of the target stripe are updated. The disk array is accessed to transfer the target stripe into the same buffer, but the buffer memory write enable is inhibited—responsive to the write mask—during transfer of the segments that were updated by the host. The complete, updated stripe is thus formed in a single buffer for parity calculations and write to the disk array.