Disk reading/writing device and readable/writable disk

摘要

In a disk reading/writing device, a chucking mechanism holds two types of disks having different outer diameters. The chucking area of a small-diameter disk is set to be less then the chucking area of a large-diameter disk. The disks are focused by an optical pickup placed on the side opposite the chucking surface. This configuration makes it possible to enlarge the data area of the small-diameter disk and to perform reading and writing from and onto the small-diameter disk with an enlarged data area.