Optical disc.

摘要

An optical disc for use in optical memories has a memory data recording surface 16 overlain by a protective cover 14 to protect it from dust and contaminants. Position related data is recorded on the outer surface 24 of the cover 14 in a more gross and less densely packed format than is the memory data on the memory recording surface 16. By removing the positional data from the memory recording surface 16, (i) more space is made available on the memory recording surface and (ii) the positional data is more easily read by a moving position scanning beam.