A multi-channel recording apparatus which is capable of recording one and the same main information by forming many parallel tracks in each of an m number of areas (m: an integer which is at least 1) among an n number of areas (n: an integer which is greater than m and is at least 2) longitudinally extending...http://www.google.de/patents/US4947271?utm_source=gb-gplus-sharePatent US4947271 - Multi-channel recording apparatus
