Patent ID: 7512045

Claim:
A medium judgment method which determines authorization of a rewritable storage medium having a read-only area and a rewritable area for use in an optical disk drive, the method comprising steps of: acquiring a specific information of the medium from an information reproduction area of the read-only area of the medium; determining whether contents of the medium are authorized based on the acquired specific information; permitting running of a starting process of the optical disk drive with the medium when the authorization of the medium is determined as being correct; and inhibiting running of the starting process of the optical disk drive with the medium when the authorization of the medium is determined as being incorrect, and wherein the method is used to read the rewritable storage medium in a read-only optical disk drive which cannot acquire the specific information from the medium, such that acquisition of the specific information from the medium is impossible, such that a request to acquire the specific information from the medium during the acquiring step causes the read-only optical disk drive to generate error information, and wherein the medium is determined to be authorized based on the error information.