Storing audio-centered information with a multi-level table-of-contents (TOC) mechanism having redundant sub-TOCs

A unitary storage medium comprising:

• at least two mutually logically conforming Sub-TOCs for each track area of one or more track areas of the unitary storage medium, thereby allowing retrieving any constituent Sub-TOC part from at least any correct copy of said at least two Sub-TOCs,
• at least one Master-TOC for specifically pointing to each of said Sub-TOCs;
• audio items stored in a first track area of the one or more track areas;
• mutually logically conforming specification of the actual configuration of the stored audio items in each of the at least two Sub-TOCs of the first track area;
• wherein there are at least two track areas.

A reader device comprising:

• a disc reader for reading either Sub-TOC of at least two mutually logically conforming Sub-TOCs for each track area of one or more track areas of a unitary storage medium, thereby allowing retrieving any constituent Sub-TOC part from at least any correct copy of said at least two Sub-TOCs, the disc reader being configured for reading one or more pointers from at least one Master-TOC for determining the position of each of said Sub-TOCs;
• the disc reader being configured for reading audio items stored in a first track area of the one or more track areas;
• the disc reader being configured for reading either mutually logically conforming specification of the actual configuration of the audio items stored in each of the at least two Sub-TOCs of the first track area;
• wherein there are at least two track areas.

A storing device comprising:

• a disc writer for writing to both Sub-TOCs of at least two mutually logically conforming Sub-TOCs for each track area of one or more track areas of a unitary storage medium, thereby allowing later retrieving any constituent Sub-TOC part from at least any correct copy of said at least two Sub-TOCs, the disc writer being configured for writing one or more pointers to at least one Master-TOC for indicating the position of each of said Sub-TOCs;
• the disc writer being configured for writing audio items to a first track area of the one or more track areas;
• the disc writer being configured for writing mutually logically conforming specification of the actual configuration of the stored audio items in each of the at least two Sub-TOCs of the first track area;
• wherein there are at least two track areas.

A method for producing a unitary storage medium, comprising the steps of:

• providing a substrate of a unitary storage medium with tracks;
• producing at least two sub-TOCs for the same track area in each of one or more track areas of a unitary storage medium, each sub-TOC having respective structures for storing access information for accessing the same content information item stored in the track area, thereby allowing retrieving the same content information item in the track area from either of the two sub-TOCs;
• and
• producing at least one master-TOC having structures for storing access information for accessing the sub-TOCs.

A unitary storage medium, comprising:

• one or more track areas;
• at least two sub-TOCs assigned to the same track area, each sub-TOC having information structures for storing access information for the same content information items stored in the track area, thereby when the medium is used with a medium reader, allowing the reader to retrieve the same content information item in the same track area using either of the at least two sub-TOCs assigned to the same track area;
• and
• at least one master-TOC with information structures for storing access information for allowing the medium reader to determine the positions of each of the mutually logically conforming sub-TOCs.