A storage disk comprising at least one data track which is composed of spiral-shaped turns or concentrical turns, the data being arranged in the form of data blocks on the turns so that between the data blocks alternately a guide segment or a blank segment is present. The lengths of the unit, measured...http://www.google.de/patents/US4094013?utm_source=gb-gplus-sharePatent US4094013 - Optical storage disk system with disk track guide sectors
