Abstract: Copy protection of an optical information carrier is provided by intentional physical modification of the information-carrying layer to affect the readability a software component stored in a specific location. By detection of the physical modification by the computer system, on which the information carrier is played back, the computer will attempt to read a specific part of a software component stored in the specific location, which is designated by a unique identification code entered into the computer either by retrieval from the information carrier itself or by user operation, e.g. via a keyboard.

Abstract: Use of an optical information carrier such as a CD-ROM (1) is limited to reading and storing if its content in a single computer device by detachment of a security member (9) bonded to a part (8) of the information or data carrying structures storing control data needed for enabling the computer device to complete reading and storing of the information on the disk. By entry into the computer device of a unique secret identification code carried by the security member (9) the computer device is enabled to resume and complete the reading and storing operations, whereas subsequent attempts of reading and storing of the information with a different computer deceive will fail due to the unavailability of the control data modified by detachment of the security member (9).