Minnesota Mining and Manufacturing Company

Imation Corporation

Bennett G Dy

Richard W Molstad

Robert J Youngquist

Robert S Bradford

Marshall R Brookhart

A track pitch error compensation system for tape drives of the type configured for reading data from and/or writing data to magnetic tape having adjacent servo tracks with apparent centerlines spaced about a tracking axis. The tape drive includes a multichannel head assembly having a plurality of channels of read gaps which produce position error signals (PES) representative of positions of the read gaps on the tracking axis with respect to the apparent centerlines of servo tracks on the tape, a positioner responsive to positioner drive signals for driving and positioning the head assembly on the tracking axis with respect to the servo tracks, and a servo control system connected between the head assembly and positioner for generating positioner drive signals causing a servoing read gap to be servo locked to a desired servo track as a function of the PES when operated in a closed-loop servo mode. The method includes determining and storing one or more track pitch error values for each magnetic tape, and determining a gain constant of the servo system. PES correction offsets representative of the magnitudes of positioner drive signals causing the positioner to drive the head assembly distances sufficient to compensate for the track pitch errors are calculated as a function of the track pitch errors and the gain constant, and stored. During closed-loop servo mode operation the PES correction offset is summed with the PES to cause the servoing read gap to be servo locked to the desired centerlines of the servo tracks.

Track pitch error compensation system for data cartridge tape drives

This invention relates to a magnetic recording head assembly and method enabling an end user to record a unique servo control track on a magnetic recording tape while the tape is in the recorder to be used for recording and playback of computer data. Previously, most such control tracks were applied only at the time of manufacture of preformatted media. The head assembly includes, in addition to a plurality of sets of read/write transducers, a servo write head having an extended transverse width for uniformly recording a servo signal across the width of a servo track section, and a servo erase head having a plurality of alternating erasing and non-erasing sections adapted to controllably erase portions of the previously recorded servo signal, resulting in unique servo control tracks.

Servo positioning system for magnetic recording media

An automatic track following feature for use with a helical video recorder is disclosed which enables reproduction of video fields at normal speeds, fast and slow forward and reverse speeds, and at stop motion, wherein a mechanism for moving a playback head transverse to the helical tracks on a magnetic tape is provided in order to enable the head to remain centered on the track regardless of tape speeds and directions of movement. A head position control signal is generated for driving the head positioning mechanism based on a comparison of a signal based on the instantaneous tape speed with a reference speed indicating signal.

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Saint Paul, MN, United States of America

Bennett G Dy