| 摘要 |
A raid disk array controller implements a write mask (16) to support partial-stripe updates from a host system (60) without expensive RAM to RAM copying and repeated disk accesses to assemble the updated stripe. New data from the host (20, 22) is transferred into a single buffer (14, 40) and a local processor (80) tracks -- by setting bits (30, 32) 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 (40), but the buffer memory write enable (58) is inhibited - responsive to the write mask (52) -- 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. |
