Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Patent
1993-06-29
1996-06-25
Psitos, Aristotelis
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
360 7303, G11B 554
Patent
active
055306020
ABSTRACT:
A starting sequence is provided for a rotating disk data storage device by providing a low level sensing current to the spindle motor which is able to initiate rotation of the disk spindle assembly when, absent stiction between head and confronting disk surface, it is only necessary to overcome disk assembly inertia and head drag. A sensing device is provided to sense a back electromotive force (EMF) in the spindle motor windings which indicates the start of disk rotation when any stiction condition has been terminated. A sequence of alternating current pulse bursts are applied to the actuator motor to impart a dithering action to the heads which induces axial vibration of the disks to break the stiction between the heads and confronting disk surfaces. The initial burst is of low amplitude pulses and each succeeding burst is of progressively greater amplitude and the pulses of each burst are of constant or progressively varying frequency to afford some consecutive pulses approaching the resonant frequency of the disk modes of vibration to enhance the stiction breaking force. The sensing of a back EMF (indicating disk rotation and the termination of any stuck head condition) is used to terminate the start sequence and switch the spindle and actuator motors to the normal operational control of the drive.
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Boutaghou Zine-Eddine
Buettner Donald C.
Larson Thomas S.
Spong Jaquelin K.
Bussan Matthew J.
Habermehl James L.
International Business Machines - Corporation
Lahtinen Robert W.
Psitos Aristotelis
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