Seagate Technology Incorporated

Jack Ming Teng

Kian Keong Ooi

Beng Wee Quak

Ming Zhong Ding

KianKeong Ooi

MingZhong Ding

Wing Kong Chiang

Louis Seng Hong Pang

Myint Ngwe

Choon Kiat Lim

YangQuan Chen

ShuangQuan Min

Ricky Wei Watt Yeo

Kwee Teck Say

Swee Kieong Choo

Soon Wah Leow

Kok Hiang Cheong

Hwee Peng Teo

Peng Yeong Loh

An information handling system, such as a disc drive, includes a base, a disc stack rotatably attached to the base, and an actuator assembly movably attached to the base. A region of the disc stack is identified as a parking band, and when power is not provided to the disc drive, the actuator assembly is held in a parked position within the parking band by an actuator latch. The actuator latch and actuator assembly have different resonant frequencies based on several environmental elements near the actuator assembly, including the temperature of the environment in the disc enclosure. The actuator assembly is unlatched by measuring the environmental element near the actuator assembly and applying an alternating current to a voice coil coupled to the actuator. The frequency of the alternating current applied to the actuator assembly during the unlatching procedure is near the resonant frequency of the actuator assembly in the measured environment.

Adaptive temperature compensated AC unlatch algorithm

A method of implementing an automatic acoustic management feature for a disc drive includes receiving an acoustic/performance compromising factor from a host, tuning disc drive performance by applying the factor to a control parameter to generate a modified control parameter, and executing a loop for controlling a disc drive operation using the modified control parameter. In another embodiment, a disc drive has a base, a rotatable disc, an actuator assembly with an arm for carrying a head in transducing relation to the disc in response to a control signal, a receiver for receiving an acoustic/performance compromising factor, and a controller that monitors the position of the arm and generates the control signal. The controller executes a seeking control loop having a control parameter modified by applying a compromising factor to the parameter to tune the acoustic performance of the drive.

Automatic acoustic management system for a disc drive

A method and apparatus for detecting and recovering from head instability in a magneto-resistive (MR) transducer head of a disc-drive system. A head-instability-recovery circuit is described for use in disc drive to recover from a head-instability condition of an MR transducer head. This circuit includes a controller and a current source that supplies current to the MR head. The current source is controlled to supply a nominal amount of current to the MR head when operating in a normal mode, and to supply one or more current bursts having a current above the nominal supply current in order to recover from the head-instability condition. Also described is a method for recovering from a transducer-instability condition of an MR transducer of a disc drive, including detecting a situation that indicates a head-instability-recovery operation is desired, and performing the head-instability-recovery operation.

Self-diagnostic MR head recovery

An information handling system, such as a disc drive, includes a base, a disc stack rotatably attached to the base, and an actuator assembly movably attached to the base. A region of the disc stack is identified as a parking band, and when power is not provided to the disc drive, the actuator assembly is held in a parked position within the parking band by a magnetic latch. The magnetic latch is overcome during a powerup process by a voice coil motor coupled to the actuator. Other regions of the disc stack are associated with various functions performed by the voice coil motor as the actuator passes over such regions.

AC unlatch using grey code detection with zone partitioning

A disc drive system and method of screening an actuator resonance includes a servo controller providing a multi-servo zone architecture. The servo controller partitions the disc into a plurality of servo zones. Each of the servo zones has a corresponding servo gain. When an actuator resonance is detected in one of the servo zones, the servo controller reduces the corresponding servo gain of the detected servo zone such that a drive with very low resonance at a certain zone does not affect the servo bandwidth of the other good zones. Accordingly, a drive with very low resonance is prevented from being scrapped. Further, the screening technique allows a drive to have an adequate servo margin for its normal operation after going through a resonance detection test.

Actuator resonance screening in disc drives

A disc drive includes a base and a disc rotatably attached to the base. The disc drive also includes an actuator assembly rotatably attached to said base and a device for moving the actuator assembly. The actuator assembly includes a transducer head in a transducing relationship with respect to the disc. The disc drive includes a disc drive controller for controlling movement of the actuator during track follow and track seek operations. The disc drive controller monitors the actuator during seek operations. The disc drive controller further computes a maximum average settle time from the monitored settle times. The dis drive controller further compares the maximum average settle time to a predetermined threshold value, and issues a command signal to adjust seek profile parameters of the disc drive to eliminate resonance in the actuator arm during a seek operation.

Self-adaptive seeking profile for resonance actuator

A method and apparatus for releasing an actuator from a latched position. A voice coil motor is operably coupled to the actuator which is held by a latch in a latched position. The voice coil motor is provided with a first current signal of increasing magnitude alternating with a second current signal out of phase with the first current signal. The first current signal causes the voice coil motor to urge the actuator away from the latched position, and the second current signal causes the voice coil motor to urge the actuator towards the latched position.

Method and apparatus for unlatching an actuator

A method to accurately determine a defective servo burst written on a recording medium having plurality of tracks, each track containing plurality of position data portions. The position data portions include servo bursts capable of providing position error information, which can be selectively retrieved by a servo control system having a servo gate enabling signal. A first likely defective servo burst is identified by reading each servo burst, measuring corresponding position error information and comparing to a range of acceptable position error information. While disabling retrieval from the first likely defective servo burst, the position error information of plurality of servo bursts occurring after the first likely defective servo burst is measured. If the measured values are within the acceptable range, the first likely defective servo burst is concluded as the first confirmed defective servo burst. If not, plurality of servo bursts occurring prior to the first likely defective servo burst are selectively disabled and subsequent servo bursts are measured until a skipped servo burst is concluded as a first confirmed defective servo burst. While disabling retrieval from first confirmed defective servo burst, subsequent servo bursts are measured to find a second likely defective servo burst. By selectively disabling retrieval of second likely defective servo burst and plurality of servo bursts prior to second likely defective servo burst, a second confirmed defective servo burst is also determined. Then the first confirmed defective servo burst and second confirmed defective servo bursts are permanently marked.

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Singapore, Singapore

Jack Ming Teng