Abstract: A data accessing method includes the steps of obtaining a track information entry about a predetermined track from a play order table, which points to a track descriptor in a track information table; obtaining the track descriptor from the track information table, the track descriptor including a decryption key corresponding to the predetermined track, pointer information that points to a part descriptor of a plurality of part descriptors in a part information table, and name pointer information that points to a name slot entry in a name table having a plurality of name slot entries; using the name slot entry and the part descriptor to read a part of an audio file according to part pointer information in the part descriptor.

Abstract: A cost-adaptive cache including the ability to dynamically maximize performance in a caching system by preferentially caching data according to the cost of replacing data. The cost adaptive cache includes a partitioned real cache, wherein data is stored in each of the real cache partitions according to its replacement cost. Also, the cost-adaptive cache includes a partitioned phantom cache to provide a directory of information pertaining to blocks of data which do not qualify for inclusion in the real cache. The partitions in the phantom cache correspond to the partitions in the real cache. Moreover, the cost-adaptive cache maximizes performance in a system by preferentially caching data that is more costly to replace. In one embodiment of the system, the cost of replacing a block of data is estimated by the previous cost incurred to fetch that block of data.

Abstract: An LUN/LBA interface is utilized to obtain the benefits of a content addressed storage (CAS) interface. Reference data is manipulated in a manner similar to a CAS system, where an object ID (OID) table is used to maintain OIDs generated for hashed LBAs. A first tier logic block is used to provide a LUN/LBA storage interface to application programs and to facilitate the writing of reference data. A second tier logic block hashes the content of reference data to be written and stores the OID generated to the first OID table. A third tier logic block facilitates writing the reference data to an LUN and to verify the accuracy of reference data to be read from the LUN. Reference data may be written to a storage area in accordance with a write-once, write-many, or write-many with versioning policy.