Abstract: A combination optical disc (1) is disclosed, which contains at least two information layers (10, 11) of at least two different storage formats selected from for example CD, DVD, BD. Information is stored on the disc (1) concerning the storage format of the layers (10, 11). According to an embodiment of the invention, each of the formats contains information indicating that a second, or even third, format is present on the same disc. Now a device may select a Format different from the one detected during start up. Alternatively, all formats present on a single disc are identified by an identifier on the disc. Such art identifier may be located in the BCA area, a chip (4) on disc or in a bar code on the disc itself.

Abstract: A combination optical disc (1) is disclosed, which contains at least two information layers (10, 11) of at least two different storage formats selected from for example CD, DVD, BD. Information is stored on the disc (1) concerning the storage format of the layers (10, 11). According to an embodiment of the invention, each of the formats contains information indicating that a second, or even third, format is present on the same disc. Now a device may select a Format different from the one detected during start up. Alternatively, all formats present on a single disc are identified by an identifier on the disc. Such art identifier may be located in the BCA area, a chip (4) on disc or in a bar code on the disc itself.

Abstract: A record carrier (1) has a servo track (4) indicating an information track (9) intended for recording information blocks. The servo track (4) has a periodic variation of a physical parameter at a predetermined frequency, usually called wobble. The servo track has modulated parts for encoding position information according to a predetermined type of modulation. The record carrier includes a management area in which the servo track includes permanent data. The permanent data is encoded using a different type of modulation, but using the variations of the same physical parameter. Direct digital modulation (41) is proposed for the different type of modulation.

Abstract: A record carrier (1) has a servo track (4) indicating an information track (9) intended for recording information blocks. The servo track (4) has a periodic variation of a physical parameter at a predetermined frequency, usually called wobble. The servo track has modulated parts for encoding position information according to a predetermined type of modulation. The record carrier includes a management area in which the servo track includes permanent data. The permanent data is encoded using a different type of modulation, but using the variations of the same physical parameter. Direct digital modulation (41) is proposed for the different type of modulation.