Disk array controller

摘要

Block data of logical inconsistency stored in a disk array is inhibited to be transferred to a host computer, by detecting a range where data was written defectively because of a power cut or the like. A processor of a disk array controller allocates a write control table within a non-volatile memory when writing data to a drive group. The write status of each disk drive in each block is supervised by a write status flag. The write statuses include a no write indication status, a writing status, and a write completed status. If all the write statuses of the same block are the write completed status or no write indication status, data is transferred to the host computer. If all the data write statuses of the same block are neither the write completed status nor no write indication status, a read error is informed to the host computer.