Abstract: When a transport rate Rs is updated, in the case where the updated transport rate Rs is within a variable range (Rc<Rs<U×Rc, and U>1) defined by a current encoding rate Rc, FEC (Forward Error Correction) data sending rate Rf is updated (Rf=Rs?Rc) without updating the current encoding rate Rc. On the other hand, in the case where an Rc update timer set to three seconds, for example, is timed out, the encoding rate Rc is updated using a minimum value Rs_min of the transport rate up to that time (Rc=V×Rs_min, and 0<V<1). Even when the transport rate Rs greatly varies to be out of the variable range, the encoding rate Rc is updated in the same manner.

Abstract: A disk device controller (1) performs reading/writing of data and management information from/to a first disk device (4) and a second disk device (5). The first disk device (4) and the second disk device (5) hold their device information and storing the management information and the data from the disk device controller (1). A reference device information holder (3) holds previously set reference device information peculiar to the device. A master disk decider (2) decides which one of the first disk device (4) and the second disk device is the master disk, based on the device information and the management information held in the first disk device (4) and the second disk device (5), and the reference device information held in the reference device information holder (3).

Abstract: When a transport rate Rs is updated, in the case where the updated transport rate Rs is within a variable range (Rc<Rs<U×Rc, and U>1) defined by a current encoding rate Rc, FEC (Forward Error Correction) data sending rate Rf is updated (Rf=Rs−Rc) without updating the current encoding rate Rc. On the other hand, in the case where an Rc update timer set to three seconds, for example, is timed out, the encoding rate Rc is updated using a minimum value Rs_min of the transport rate up to that time (Rc=V×Rs_min, and 0<V<1). Even when the transport rate Rs greatly varies to be out of the variable range, the encoding rate Rc is updated in the same manner.

Abstract: A disk device controller (1) performs reading/writing of data and management information from/to a first disk device (4) and a second disk device (5). The first disk device (4) and the second disk device (5) hold their device information and storing the management information and the data from the disk device controller (1). A reference device information holder (3) holds previously set reference device information peculiar to the device. A master disk decider (2) decides which one of the first disk device (4) and the second disk device is the master disk, based on the device information and the management information held in the first disk device (4) and the second disk device (5), and the reference device information held in the reference device information holder (3).