Patent ID: 7372790

Claim:
An information system, comprising: an optical disc having information marks recorded therein along a track, said information marks exhibiting first variations in a track-wise direction and second variations in a substantially radial direction, said first variations representing a main data recorded on said optical disc and caused by existence and nonexistence of the information marks along the track, and said second variations being wobbled information marks that are deviated in the substantially radial direction, said first variations and said second variations being coupled such that a single string of information marks along a track includes both main data and other data that is conveyed by the information marks deviated in the substantially radial direction; an optical pickup including a transducer unit configured to scan said optical disc and detect said first variations and said second variations; a first recovery unit coupled to the optical pickup that recovers a clock signal from the first variations; a second recovery unit coupled to the optical pickup that recovers the main data from the first variations; and a detection unit configured to detect whether said second variations exhibit a predetermined variation pattern on the basis of at least one signal indicative of said second variations, wherein the detection unit is configured to use the clock signal for detection, and an enabling unit to recover the main data when said detection unit detects said predetermined variation pattern.