Abstract: Methods and apparatus are provided for tuning out time constant deviations of a network (414) due to process, voltage, and temperature variations. The apparatus (400) comprises a clock reference (404) from which a digital time constant is correlated to the nominal time constant of the network (414). The correlated digital time constant is applied to the network (414), and the output charge/discharge waveform swing is compared to a predetermined reference voltage. If the charge/discharge waveform swing does not match the reference voltage, an offset signal is generated. The offset signal is applied to a control circuit (402) that generates a corresponding tuning signal. The tuning signal is applied to the network (414) to adjust the internal components incrementally until a match is achieved. The apparatus (400) can be configured as a built-in self-test digital time constant tracking circuit, and can be integrated with the network (414) on an IC chip.

Abstract: In a magnetic storage system, an error recovery is performed by reading the magnetic medium again with the filter programmed to a higher boost. If the retry still fails, the magnetic medium is read again with the filter programmed to a lower boost. The filter adjustment can be performed in combination with position adjustment of the read head, i.e. displacing the read/write head from the centerline of the track during error recovery to reduce read errors.

Abstract: A technique for operating a data storage medium, such as a magnetic tape cartridge, by writing pairs of buried servo data tracks having alternating flux densities. A servo read gap is used to locate the on-track position at the border between a pair of servo tracks by detecting a fixed relationship, such as a predetermined proportionality correction factor, between the signals read from each track. Information data read and write gaps are mounted to the servo read head to create a plurality of information data tracks, each one half or less the width of a servo data track or smaller and separated from the next track by one half the servo track width. Information data tracks are formed in these separations between tracks by positioning a second servo data read head at a distance equal to the width of an information data track pitch from the first servo read head while using the second servo read head to locate the on-track position.