Abstract: A fast access high capacity data storage system and method are disclosed, the data storage system including a disk-based storage system employing a plurality of storage surfaces. Selected storage surfaces have a plurality of independently controlled data access heads in data communication therewith, and circuitry is provided for allowing concurrent data transfers through the plurality of data access heads. Performance is further improved by monitoring frequently accessed data records and transferring them to a copy recording surface or recording surfaces less frequently used, and by moving a data access head of the plurality of data access heads to other recording surfaces to decrease access bottlenecks. The storage system further includes circuitry for averaging at least one of record length data, transfer timing data, access timing data and address data.

Abstract: An optical information recording/reproducing system is disclosed in which optical information having guide grooves for tracking and information pits beforehand provided thereon is irradiated with a main light beam for the recording/reproduction of information and a pair of subsidiary light beams for the detection of tracking and the scanning loci of the centers of the subsidiary light beams are arranged on the optical information carrier on opposite sides of the scanning locus of the center of the main light beam, respectively, first and second means for generating electric signals having their amplitudes corresponding to the respective intensities of the subsidiary light beams reflected by the optical information carrier, third means for detecting a difference in amplitude between the electric output signals of the first and second means, fourth means for detecting Ac components of the electric output signals of the first and second means to detect a difference in amplitude between the AC components, and fif

Abstract: A method of detecting a light spot control signal is disclosed in which, when information is reproduced from an optical disk for optically recording information, a signal level obtained at a high-reflectivity portion of the optical disk is taken out of a signal reproduced from the optical disk, and is used as a control signal, which controls a light spot so that it tracks information stored in the optical disk.

Abstract: The difference between the two gain control signals for two amplifiers which correspond to two of a plurality of read heads which have the maximum and minimum output levels is detected. Whether or not the difference exceeds a predetermined value indicates an abnormality of the outputs of the read heads due to dust adhering thereto.