Patent ID: 8041850
Filing Date: 2011-10-18
Classification: G06F

Abstract:
1. A storage apparatus, comprising: a channel control unit that communicates with a host computer; a disk control unit that controls a hard disk drive; and a cache memory accessible by the channel control unit and the disk control unit, wherein the channel control unit that, upon receiving an I/O request from the host computer, sends or receives data to or from the disk control unit via the cache memory, the data to be written to or to be read from the hard disk drive in accordance with the I/O request, the channel control unit includes a variable-length DMA (Direct Memory Access) that performs data transfer of variable-length data sent or received to or from the host computer in accordance with the I/O request, a fixed-length DMA that performs data transfer of fixed-length data to and from the cache memory, and a buffer intervening between the variable-length DMA and the fixed-length DMA, the fixed-length DMA, in performing the data transfer of the fixed-length data to the cache memory, is configured to: divide the variable-length data into a plurality of data sets add a first integrity code to a first data set which is one of the plurality of data sets, for integrity assurance of the plurality of date sets, the size of the first data set with the first integrity code is a first size which is equivalent to the size of each of the other ones of the plurality of data sets, add a second integrity code to each of the plurality of data sets for integrity assurance of the respective date sets, the size of each of the plurality of data sets each including the second integrity code is a second size which is equivalent to a unit size of data managed in the cache memory, and transfer the plurality of data sets each including the second integrity code as a plurality of fixed-length data sets to the cache memory, and wherein the second integrity code is eliminated from the respective data sets if the hard disk drive is a first type drive so that the plurality of fixed-length data sets in which each size is the second size can be managed as a plurality of fixed-length data sets in which each size is the first size, which is equivalent to a unit size of data managed in the first type drive.