Abstract: An optical disk drive system with which data may be permanently and correctly stored on removable media. The system includes a drive into which the media, a disk housed in a cartridge, may be removably inserted. The drive interfaces with a host CPU through a storage control unit, which storage control unit may also have other peripheral devices, such as magnetic disk drives, coupled therethrough to the host CPU. A special data format is used for data stored on the disk in order to provide efficient use of and access to the available storage space. The disk is divided into data bands, each data band having a prescribed number of concentric data tracks therein. Each data track is divided into equal length sectors. The data is organized into data blocks, each block being made up of a selected sequence of prescribed data sections. Many of the data sections commence with synchronization bits followed by the data to be stored. The data of each data section is adapted to fit within each data sector on the disk.

Abstract: A self-checking shared encoder/decoder circuit for use with a Reed-Solomon coding scheme of an optical disk storage system. The optical disk system includes a drive adapted to permanently store data on a removable platter. Prior to recording a data byte on the platter, the data is encoded with a Reed-Solomon code. When the data is read from the disk, it is decoded and error correction syndromes are generated. A plurality of syndrome buffer registers are provided in order to allow several of the error correction functions to be carried out in parallel. Syndromes that are detected to comprise all zeros are used to simplify the error correction processes beyond the normal processes used. The same circuitry is shared for performing the encoding and decoding functions. This circuitry includes independent sets of a RAM, coupled to one input of an exclusive OR (modulo two sum) adding circuit. The output of the adding circuit is fed back to an input of the RAM.

Abstract: A shared encoder/decoder circuit for use with a Reed-Solomon coding scheme of an optical disk storage system. The optical disk system includes a drive adapted to permanently store data on a removable platter. Prior to recording a data byte on the platter, the data is encoded with a Reed-Solomon code. When the data is read from the disk, it is decoded and error correction syndromes are generated. The same circuitry is shared for performing the encoding and decoding functions. This circuitry includes independent sets of a RAM, coupled to one input of an exclusive OR (modulo two sum) adding circuit. The output of the adding circuit is fed back to an input to the RAM. Two multiplier circuits are coupled to the output of the RAM. A product of one is tied to one input of the modulo two addition circuit.