Storage device and method of instructing to update firmware

A storage device comprising:

• a plurality of expanders connected to a disk device which stores data transmitted from a host device;
• and
• a controller unit for controlling the expanders,
• wherein the controller includes a determination unit for determining whether or not, when download data is received from a predetermined terminal in order to update firmware of the expanders, it is necessary to initialize a corresponding expander after downloading the download data by the expander, a transmission unit for transmitting initialization determining information determined by the determination unit to the terminal, and an update instruction unit for transmitting the download data to the corresponding expander and instructing the corresponding expander to update the firmware at timing for updating the firmware, which is determined by the terminal based on the initialization determining information transmitted from the transmission unit, and
• wherein, upon the determination unit determining that it is necessary to initialize the corresponding expander and being instructed to update the firmware from the terminal when the expander transmits data to and receives data from the host device with a frequency equal to or lower than a predetermined frequency of transmission/reception of data, the update instruction unit transmits the download data to the corresponding expander and instructs the corresponding expander to update the firmware upon a frequency of transmission/reception of data being equal to or lower than the predetermined frequency.