Burroughs, Inc.

Michael Isaac Behr

Wilfred D Iwan

Ko Ko Gyi

Norman S Blessum

Werner Brutsch

KoKo Gyi

Joseph C Palotay

Method and apparatus for providing coarse and fine radial positioning of a multiple head assembly relative to the concentric tracks of a rotatable magnetic disk. In addition to a plurality of data heads, the head assembly also includes a pair of position sensing heads having skewed core gaps disposed at an angle with respect to each other. These position sensing heads are used for prerecording concentric position control tracks on the disk as well as for subsequent sensing of position control information during both coarse and fine positioning operations. The position control information prerecorded in the position control tracks is specially chosen so as to provide a pair of pulse trains during position sensing having characteristics such that highly accurate and reliable control of head position can be achieved based upon a detection of the coincidence relationship between predetermined pulses of the respective pulse trains.

Transducer positioning system

Data is recorded on a magnetic recording disk with data transducers adjustably positioned relative to respective 'data zones,' each zone comprising a prescribed number of adjacent data tracks. A family of such transducers may be mounted together as a unitary recording head which is positionable radially over an excursion approximating the width of the (multi-track) data zones. A typical head reciprocation excursion approximates from one dozen to several dozen mils; thus, the heads are aptly mounted on flexure pivots and reciprocated directly by electro-magnetic means which are mechanically isolated from the head array.

Flexure mounted magnetic head positioner for high-speed translation

In the manufacture of a transducer head, a plurality of elongated slots are formed in a non-magnetic substrate to receive magnetic cores having a transducing gap. A sealing composition bonds the cores in the slots and the cores are then laser trimmed to predetermined widths and at predetermined core-to-core spacings.

Transducer head with narrow core structure

Method of making a transducer head with narrow core structure

Data is recorded on a magnetic recording disk with data transducers adjustably positioned relative to a data zone. First and second control tracks are interspersed with the data zone in a parallel relationship. Positioned over each control track is a position sensing transducer mechanically linked to the data transducers. The control transducers each comprise core gaps used both for prerecording and subsequent reading of a position control pattern along their respective tracks. The core gaps extend diagonally at a predetermined angle to the direction of movement of the medium and provide control patterns defining multiple transition groups, the number of transitions related to a corresponding number of data tracks to be read by the data transducers. Positioning of the position sensing transducers is accomplished by measuring the time relationship between the output pulses of the two control tracks and by relating the resulting time differential to the radial distance over which the control head is to be actuated.

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South Pasadena, CA, United States of America

Michael Isaac Behr