Abstract: To update a firmware without stopping an operation of a disk array apparatus. The disk array apparatus includes a plurality of disk devices providing redundancy, a disk array control device, and a disk controller for controlling the disk devices individually in response to a command issued from the disk array control device. The disk array control device designates a disk device to be updated based on contents of the firmware update command for the disk device, controls firmware update for the designated disk device, disconnects the designated disk device from the host computer temporarily, sets the disk device as being in a temporary degenerate state, and, when a data write or read command is issued from a host computer for the disk device being in the temporary degenerate state, designating a different disk device to execute the command issued from the host computer by using redundancy of the disk devices.

Abstract: To update a firmware without stopping an operation of a disk array apparatus. The disk array apparatus includes a plurality of disk devices providing redundancy, a disk array control device, and a disk controller for controlling the disk devices individually in response to a command issued from the disk array control device. The disk array control device designates a disk device to be updated based on contents of the firmware update command for the disk device, controls firmware update for the designated disk device, disconnects the designated disk device from the host computer temporarily, sets the disk device as being in a temporary degenerate state, and, when a data write or read command is issued from a host computer for the disk device being in the temporary degenerate state, designating a different disk device to execute the command issued from the host computer by using redundancy of the disk devices.