Patent ID: 7058760

Claim:
A disk device, comprising: a write buffer storing data for a write command received from a host; a command queue storing commands for which a disk medium access operation has not been completed; a reordering processor returning a data write acknowledgment and selecting from write commands stored in the command queue a next write command to be executed, the next write command to be executed being a command having a starting data storage address on the disk medium that can be reached in the least amount of time from an address on the disk medium at which the last data of a command currently being executed is stored; a command processor executing the command selected by the reordering processor; a continuous access decision unit storing in memory a starting address and an ending address of the accessed data from a previous command for write commands input continuously over time, and determining that an access is continuous if the starting address of the accessed data for a new write command is between the starting address and the ending address of the accessed data of the previous command; a write buffer storage device overwriting the data from the previous command in the write buffer and storing the write data from a host in a specified position in the write buffer; and a continuous access command storage unit storing a continuous series of write commands, wherein a continuous access operation is performed by moving a write data storage location for a new command to the starting position of the overlapping data when, in the write commands that are input continuously over time, an earlier half of accessed data for a new write command overlaps with a later half of the accessed data for the previous command.