| | Documents concerning relative positioning or movement of transducers and record carriers are classified in groups G9B/3 to G9B/7 and G9B/21when only the transducer is controlled and in groups G9B/15, G9B/17 and G9B/19when only the record carrier is controlled.When both record carrier and head are controlled, the documents are classified in G9B/15.022, G9B/15.023, G9B/19 andG9B/27.001. When a plurality of record carriers are controlled, the documents are classified in G9B/15.135, G9B/17.041, G9B/17.051 andG9B/27.001. By "access" is meant an operation including a relative movement for positioning between record carrier and head before, during or after transducing; this operation including "seek", "select", "change", "acquire" and "follow" functions for at least a part of a track on at least one record carrier. By "programmed access" is meant a sequence of access operations the result of the sequence being to acquire a want ed sequence of parts of tracks or a wanted sequence of tracks. Relative movement between head and record carrier also covers the movement of a coupling beam such as a light beam between the head and a stationary record carrier. "Movement of the head" also covers any virtual movement or any physical movement such as obtained by switching between successive transducing parts of the head or by moving the transducing zone of the head, i.e. by "scanning". If different transducing parts of the head are switchable, the number of transducing parts should be much smaller than the number of individual storage areas of the record carrier. Attention is drawn to the notes of subclass G11C.] |
