Patent ID: 8364927

Claim:
A disk array system coupled to a host computer, comprising: a plurality of hard disk drives capable of changing operating modes based on particular parameter information; at least one expander device including a memory and a plurality of ports each coupled to one of the plurality of hard disk drives; and a disk controller being coupled to the at least one expander device and controlling data transfer between the host computer and the plurality of hard disk drives via the at least one expander device, wherein the at least one expander device manages a particular parameter value for each port coupled to one of the plurality of hard disk drives on the memory thereof, and optimizes the status of the data transfer between the host computer and each of the plurality of the hard disk drives based on the particular parameter value for each port thereof, wherein each of the plurality of hard disk drives stores respective particular parameter information regarding a particular parameter value suited for a high-speed communication mode, and wherein the disk controller is configured to: control, as triggered by attachment of a first hard disk drive of the plurality of hard disk drives, the first hard disk drive and the at least one expander device including a first port of the plurality of ports coupled to the first hard disk drive to link up in a low-speed communication mode; read the particular parameter information from the first hard disk drive in the low-speed communication mode; update the particular parameter value for the first port managed on the memory of a first expander device of the at least one expander devices; and control the first hard disk drive and the first expander device to link up in the high-speed communication mode using the updated particular parameter value for the first port.