Reproduction circuit in an optical disk reproduction apparatus

摘要

An optical data disk comprises an identifier in a prescribed region for indicating whether a barcode-like mark is present or not on the disk. The prescribed region is a control data area in which physical feature information regarding the optical disk is recorded, and the disk further comprises a guard band area in which at least an address is recorded, said guard band area being disposed between the area where the barcode-like mark is recorded and the control data area. Further, a reproduction apparatus for use with a disk of the afore-mentioned type is disclosed.