Abstract: The half-inch tape drive comprises a novel takeup reel, tape deck, PC board packaging, loading mechanism, and housing. The takeup reel comprises a pair of segmented flanges that define a first and second tape containment section. The tape deck is approximately half the height of a conventional tape deck and includes reinforcing ribs to provide structural rigidity and maintain alignment of the moving components of the tape drive during operation. The loading mechanism comprises a horizontally mounted load motor that employs a worm gear to engage a simplified gear train. The printed circuit board is segmented into multiple sections that are mounted in various locations on the tape drive to maximize spatial efficiencies and reduce the overall height of the tape drive. The tape drive housing provides a protective exterior for the tape drive components and provides the structure for mounting the present tape drive in a single drive bay of a computer housing.

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 system and method for generating a unique sync pattern that may be appended to a selected data sector of a disk storage system. The data to be stored in the disk storage system is encoded in accordance with a desired fixed rate run-length limited code, such as a 2,7 code. The unique sync pattern is generated by first encoding a prescribed data word in accordance with the desired code. At least one bit of the encoded prescribed data word is then changed in a manner such that the changed encoded word still complies with the coding rules of the desired code, yet the resulting bit pattern does not represent any valid sequence of data in accordance with the desired code. Hence, the changed encoded word may be readily distinguished from data, thereby providing the synchronization function, while still being handled and processed by the same encoding/decoding circuitry as is employed to handle and process the data.

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.