US Patent 7623426 Optical disk apparatus

An optical disk apparatus which records data on the basis of a predetermined minimum amount of recording data. Recording data supplied from an external device is stored in a buffer memory and then encoded and recorded on an optical disk. The data is recorded in units of one ECC block (sixteen sectors). When the buffer memory has a free space corresponding to data amount of less than one ECC block, a system controller supplies a request for data in a data amount of the free space to the host device to store data corresponding to one ECC block in the buffer memory, as a result of which data filling by means of access to the optical disk is prevented.