DR. HIEU CHI NGUYEN, M.D.
Marriage and Family Therapists at Park Ave, Oklahoma City, OK

6342986, Jan 29, 2002

Dec 8, 2000

09/732975

Hieu V. Nguyen - Oklahoma City OK

Seagate Technology LLC - Scotts Valley CA

G11B 2102

360 75, 360 53, 360 66

Apparatus and method for servo writing with simultaneous biasing of multiple magneto-resistive read elements in a disc drive head/disc assembly. A preamplifier circuit sequentially applies read bias currents to successive pairs of heads of the head/disc assembly, wherein the read bias current applied to a selected one of each pair of the heads is used to transduce the servo data from the associated disc recording surface, and the read bias current applied to the remaining one of each pair of the heads is used to prepare the remaining one of each pair of the heads to subsequently transduce the servo data from the associated disc recording surface. The preamplifier circuit includes at least first and second read bias current sources and a head selection circuit.

6532126, Mar 11, 2003

Aug 15, 2000

09/639211

Hieu Van Nguyen - Oklahoma City OK

Seagate Technology LLC - Scotts Valley CA

G11B 1512

360 63, 360 66

An apparatus and method are disclosed for minimizing damage to a disc drive during head switching operations. The disc drive comprises a plurality of magnetic recording surfaces to and from which data are transferred using read/write heads, each head utilizing the application of a bias current during operation. To switch from a presently selected head to a target head, the disc drive determines a first value indicative of the magnitude of a bias current for the presently selected head and a target bias current to be applied to the target head. When the second value is greater than the first value, the disc drive switches from the presently selected head to the target head and then applies the target bias current; conversely, when the first value is greater than the second value, the target bias current is applied to the presently selected head and then the disc drive switches from the presently selected head to the target head.

6356404, Mar 12, 2002

Jun 4, 1999

09/326092

Hieu V. Nguyen - Oklahoma City OK

Seagate Technology LLC - Scotts Valley CA

G11B 503

360 66, 360 46, 360 63

Apparatus and method for simultaneously biasing multiple magneto-resistive read elements in a disc drive head/disc assembly. A preamplifier circuit sequentially applies read bias currents to successive pairs of heads of the head/disc assembly, wherein the read bias current applied to a selected one of each pair of the heads is used to transduce the servo data from the associated disc recording surface, and the read bias current applied to the remaining one of each pair of the heads is used to prepare the remaining one of each pair of the heads to subsequently transduce the servo data from the associated disc recording surface. The preamplifier circuit includes at least first and second read bias current sources and a head selection circuit.

6611397, Aug 26, 2003

Jun 4, 1999

09/326068

Hieu V. Nguyen - Oklahoma City OK

Seagate Technology LLC - Scotts Valley CA

G11B 5596

360 7708, 360 25, 360 31, 360 7706

Apparatus and method for improving operational performance of a disc drive by detecting defective servo burst patterns. A rotatable disc is provided with servo data which include a plurality of servo burst patterns to define a plurality of tracks. A head transduces the burst patterns to provide burst signals to a servo circuit which controllably positions the head with respect to the surface of the disc by determining a position error signal from a combination of the burst signals. The servo circuit identifies a selected servo burst pattern as defective in relation to differences between absolute values of successive pairs of peak amplitude samples from the burst signal.

6349009, Feb 19, 2002

Jun 4, 1999

09/326069

Housan Dakroub - Oklahoma City OK
Hieu V. Nguyen - Oklahoma City OK

Seagate Technology LLC - Scotts Valley CA

G11B 502

360 68, 360 45, 360 46, 3602459

Apparatus for improving data writing operations to a disc recording surface of a disc drive. A head assembly is supported over the disc recording surface by a flexible suspension assembly of a controllably positionable actuator assembly and includes a write current shaping circuit integrated with a write element. The write current shaping circuit modifies write currents received by the head assembly via a transmission line from a preamplifier driver circuit to remove undesired characteristics from the received write currents. The write element writes data to the disc recording surface using the write currents as modified by the write current shaping circuit.

6115201, Sep 5, 2000

Mar 18, 1998

9/040667

Karl Louis Enarson - Yukon OK
Deanne Sue Grover - Oklahoma City OK
Hieu Van Nguyen - Oklahoma City OK
John Michael Baker - Tuttle OK

Seagate Technology, Inc. - Scotts Valley CA

G11B 503

360 66

An apparatus and method are disclosed for determining a maximum magnitude of bias current that can be safely applied to a head of a disc drive. The disc drive comprises a head disposed adjacent a rotatable disc having a recording surface on which data are magnetically stored, a preamplifier circuit which selectively applies bias currents to the head, and a head bias current selection circuit, operably coupled to the preamplifier circuit, which first determines the maximum magnitude of bias current that can be applied to the head in relation to a maximum power dissipation rating of the head and voltage measured across the head when at least one initial bias current of selected magnitude is applied to the head. Thereafter, a range of bias currents having different magnitudes less than or equal to the maximum magnitude are selected and evaluated to select an optimum magnitude for subsequent use by the drive.

6141165, Oct 31, 2000

Mar 18, 1998

9/040795

Hieu Van Nguyen - Oklahoma City OK
Clyde Everett Goodner - Midwest City OK

Seagate Technology, Inc. - Scotts Valley CA

G11B 1512, G11B 503

360 63

An apparatus and method are disclosed for minimizing damage to a disc drive during head switching operations. The disc drive comprises a plurality of magnetic recording surfaces to and from which data are transferred using read/write heads, each head utilizing the application of a bias current during operation. To switch from a presently selected head to a target head, the disc drive determines a first value indicative of the magnitude of a bias current for the presently selected head and a target bias current to be applied to the target head. When the second value is greater than the first value, the disc drive switches from the presently selected head to the target head and then applies the target bias current; conversely, when the first value is greater than the second value, the target bias current is applied to the presently selected head and then the disc drive switches from the presently selected head to the target head.

6266202, Jul 24, 2001

Jun 4, 1999

9/326070

Hieu V. Nguyen - Oklahoma City OK
Housan Dakroub - Oklahoma City OK

Seagate Technology LLC - Scotts Valley CA

G11B 509, G11B 2736

360 53

An apparatus and method for performing real-time, closed loop write verification in a disc drive having a rotatable magnetic disc and a head having read and write elements. During a write operation, the disc drive generates a write current signal indicative of input data to be written to the disc. The write current signal is applied to the write element, which generates a time-varying magnetic field to simultaneously induce a readback signal in the read element through magnetic coupling of the read element to the write element, and to magnetize the disc to write the input data to the disc. The readback signal induced in the read element is used to reconstruct a set of output data which is used to verify accuracy of the input data.

5146372, Sep 8, 1992

Jun 19, 1990

7/540099

Robert Cronch - Oklahoma City OK
Mark D. Hertz - Oklahoma City OK
Hieu V. Nguyen - Oklahoma City OK

Seagate Technology, Inc. - Scotts Valley CA

G11B 509

360 51

Window center settings in a read channel of a magnetic disk drive are controlled. The magnetic disk drive is suitable for reading data from a magnetic disk. A number of read operations are performed and data is read from the magnetic disk. Read errors are detected during the read operations. The number of read errors is recorded and error types are determined. Adjustment of the window center settings is controlled based on the number of read errors detected and the error types determined.