A method of installing software on a storage device controlling apparatus which includes at least one channel controller having a circuit board on which are formed a file access processing section receiving requests to input and output data in files as units from an information processing apparatus via a first network and an I/O processor outputting I/O requests corresponding to the requests to input and output data to a storage device; at least one disk controller executing input and output of data into and from the storage device in response to the I/O requests sent from the I/O processor; and a second network connecting the channel controller and the disk controller so as to be able to communicate with each other, the method comprises the step of writing software for enabling the file access processing section to function, into the storage device by communicating with the channel controller via the second network.