Main data records are recorded in a first area of a non-rewritable optical disk and index records used for retrieving the main data records are recorded in a second area. Each index record includes a code data to be used as an index, and a provisional order which is an order of the code data to be registered,...http://www.google.de/patents/US4760526?utm_source=gb-gplus-sharePatent US4760526 - Method for storing data into a file device and for data retrieval
