Digital optical data disc has two disc surfaces, of which one carries a data recording in CD format and the other in DVD format, and marking(s) indicating format with which side is encoded

摘要

The digital optical data disc has two disc surfaces, of which one carries (20) a data recording in CD format and the other (21) in DVD format. At least one disc surface has a marking (30) indicating the format with which the side is encoded, e.g. CD or DVD. The DVD surface contains information about the data stored on the CD side.