Additional data channel in between marks

摘要

A device has a head for recording information by writing marks in a track on a record carrier via a beam of radiation. The radiation is controlled to write the marks ( 40 ) having a main mark intensity ( 44 ) and a mark length within a predefined range of mark lengths. Further secondary marks ( 41 ) are recorded in the same part of the track. The secondary marks have a secondary mark intensity ( 43 ) that is substantially different from the main mark intensity and a length substantially longer than mark lengths in the predefined range. Furthermore a record carrier, method of recording and a read device are described.