Seagate Technology Incorporated

T Jay Cameron

Duc T Phan

Frederick Frank Kazmierczak

Stanley H Dinsmore

A system and method for unloading a transducer assembly to a ramp positioned outside an outer diameter of a disc in a disc drive system directs current generated from the back EMF (electromotive force) of a spindle motor to supplement current provided by a power supply to a positioning coil. The combined current yields increased torque to park the transducer assembly without requiring unnecessary power consumption during normal disc drive operation. The current generated from the back EMF of the spindle motor is enhanced by accelerating the rotation of the spindle motor to exceed the normal operational rotational velocity of the disc drive system. A position detector provides a trigger signal to control the timing of the switch that combines the current from the back EMF and the current from the power supply to the positioning coil. A modified voice coil motor configuration optimizes the magnetic flux density along the length of the voice coil motor magnets so as minimize unnecessary power consumption while optimizing the magnetic flux density in the region corresponding to the disc surface.

Supplying power from a spindle motor in a disc drive system

For low velocity retraction of a disc drive actuator during a parking operation, a system comprising a voltage generator circuit generates a plurality of discrete dc voltage levels, a timing circuit provides a series of timing pulses, and a selection circuit responsive to the voltage generator and timing circuit outputs a voltage profile of increasing voltage steps from the voltage levels and the timing pulses. The voltage profile is provided to a driver circuit that drives a voice coil motor which, in turn, positions the actuator with respect to the discs of the disc drive. The application of the voltage profile during the parking operation causes the driver circuit to act as a voltage source for the voice coil motor. External bias forces upon the actuator tending to force the actuator towards the park position generate a back EMF in the coil, opposing the voltage source of the driver circuit and the motion of the actuator towards the park position. The coil is thus velocity limited and the voltage profile is selected to bring the actuator to the park position at a terminal velocity sufficiently decreased as to generate acoustic noise below predetermined, acceptable limits.

Applying a ramped voltage source across an actuator coil to retract a disc drive actuator

A narrow read head and a wider write head are used to store and retrieve data from a storage medium, such as a magnetic disk or tape. The wider write head is selectively positioned to record overlapping data tracks. The read head is subsequently positioned to read the non-overlapping portions of the data tracks. In one format, a read seldom data block is recorded by sequentially recording a plurality of data tracks such that each subsequent data track partially overlaps a previously written data track. In another format, pairs of data tracks are recorded by side-by-side, wherein within each pair of data tracks there is an overlapping region. In either format, the narrower read head is positioned to read the non-overlapping portions of the data tracks. Consequently, the storage capacity of the storage medium is optimized to take advantage of the narrow read head.

Methods and apparatus for overlapping data tracks on a storage medium

The method disclosed is generally directed to a process for controlling the velocity of an actuator arm assembly during a load from a ramp. A process in accordance with the invention includes applying an alternating current to the VCM to eliminate frictional effects. An increasing current is applied to the VCM. The increasing current is an increasing function of time in one embodiment of the invention and is determined such that the heads are loaded at a predetermined velocity. In one embodiment, the predetermined velocity is 1 in/sec.

Low velocity disk drive load controller

A ramp loading and unloading system for the heads in a disc drive including an integrated latching mechanism for the disc drive actuator. The flexures that support the heads include ramp contact features which engage the ramps, and at least one of the ramp contact features includes a vertical latching face. At least one of the ramps includes a discontinuity forming a ramp latching face with which the vertical latching face of the ramp contact feature engages to latch the actuator. The ramp structure also includes a pivoting member which is rotated under influence of the actuator to allow the latching faces of the flexure and ramp structure to disengage.

Load and unload ramp with integrated latch

A direct access storage device (DASD) employs a servo including a digital signal processor having a software switch (DSP). The DSP is provided with DSP code in a DSP code space. One of the functions of the DSP code is to implement the microstep calibration of the present invention. Microstep calibration is accomplished by a step change of head position within a single track. In head position 1 the head is at the center of the track in track follow mode. From head position 2 to head position 3, an offset command causes the servo to move the head slightly off center. From head position 3 to head position 4, the servo is disabled by opening the software switch in the DSP. The position delta, delta 3-4, of the head is recorded. From position 4 to position 6, the servo is still disabled and a step of current is applied to the VCM to determine position delta 2. From position 7 to position 8, the servo is still disabled and two steps of VCM current are applied to recover to the offset position. From position 9 to position 10, the servo is enabled by operating the software switch within the DSP with the offset still applied and the result is that the offset position is re-established. Delta 3-4 and delta 4-6 are used to determine the system gain. The measured gain is applied to the DSP as a kgain parameter which is used by the DSP to correct for variation and measured system gain.

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Corralitos, CA, United States of America

T Jay Cameron