In a disc drive device (10) described as a specific embodiment of the
present
invention, AC0 to AC14 of ADIP cluster address are associated with
address bits AU6 to AU20 of an address unit. On the basis of 8-bit
sector address on the lower side of cluster address arranged in ADIP address of
a conventional MD, 0/1 representing sector address FC to 0D of a
former-half cluster and sector address 0E to 1F of a latter-half
cluster of a sector of a next-generation MD(1) is associated with address
bit AU5 of the address unit. To a part (110) of 4 address bits AU4
to AU1 below this, 4 bits representing individual parts obtained by
equally dividing one recording block by 16 are allocated. Thus, a higher-density
data volume can be handled without causing any inconvenience while utilizing an
existing recording format.
