Western Digital Technologies, Inc.

Western Digital Corporation

Carl R Messenger

Michael J Cullen

Raffi Codilian

Robert P Ryan

David D Nguyen

Russ A Quisenberry

Steven Nemshick

Ross E Gough

Terry C Dawson

Steven Neal Rivkin

Karsten C Strecke

Jan G Abrahamsson

Arun Makhija

Gordon K Rydquist

A data storage device (DSD) test system is disclosed comprising a first DSD tester operable to download a first version of an operating system to a first DSD and execute a first test on the first DSD, and a second DSD tester operable to download a second version of the operating system to a second DSD and execute a second test on the second DSD while the first DSD tester is executing the first test on the first DSD.

Testing data storage devices running different versions of an operating system

A method of binning disk drives by evaluating quality metrics prior to a final quality audit is disclosed. A number of disk drives are assembled, and a plurality of quality metrics are generated for each disk drive representing a plurality of operating characteristics. The quality metrics for each disk drive are evaluated for binning the disk drives into a plurality of lots including a first lot and a second lot. A final quality audit (FQA) is performed by executing a number of write and read operations for a plurality of the disk drives in each lot and classifying each disk drive as passing or failing the FQA. If the number of disk drives that fail the FQA out of the first lot falls below a first threshold, the first lot is classified as acceptable for a first tier customer. If the number of disk drives that fail the FQA out of the second lot falls below a second threshold, the second lot is classified as acceptable for a second tier customer.

Binning disk drives during manufacturing by evaluating quality metrics prior to a final quality audit

A method for identifying defective data sectors in a disk drive comprising generating a test pattern on a portion of a disk surface; reading the test pattern on the portion to detect an error and if an error is detected: associating the error with a physical location on the portion to identify a defective area unsuitable for user data; and assigning a severity category to the defective area. The method further comprises providing a physical defect list (P-list) for listing each defective area, the P-list having a predetermined limit to restrict a number of P-list entries; and posting the defective areas having a first severity category to the P-list and if the P-list limit is not exceeded by the first severity category entries: posting defective areas having a second severity category to the P-list.

Identifying defective data sectors in a disk drive

A controller for a disk drive that accesses a look up table having a plurality of thermally characterized values corresponding to a plurality of seek operations. For each seek operation, the corresponding value is added to a register. The controller decrements the register at a rate that is determined using servo interrupts occurring as a result of the rotation of the disk. When the value of the register exceeds a threshold, the controller adjusts the subsequent seek operation so as to inhibit damage to the voice coil as a result of overheating.

Disk drive with efficient coil temperature estimation

A disk drive is connectable to a power supply voltage and includes a spindle motor, a spindle motor driver, a spindle motor controller, and a detector. The spindle motor has windings and a rotatable rotor. The spindle motor driver is connected to the windings and connectable to the voltage. The spindle motor controller commands the spindle motor driver to apply the voltage across at least one of the windings to cause the rotor to rotate, which induces a BEMF having a polarity across each of the windings. The spindle motor controller subsequently commands the spindle motor driver to remove the applied voltage across the windings, and the detector monitors the BEMF in each of the windings to detect the polarity of the BEMF in each of the windings to generate a previous multi-bit sequence representing a previous phase position ({circumflex over (&thgr;)} ) of the rotor and subsequently detect a change in the polarity of the BEMF in one of the windings to generate a present multi-bit sequence representing a present position (&thgr; ) of the rotor. The spindle motor controller is responsive to the previous phase position ({circumflex over (&thgr;)} ) and the present phase position (&thgr; ) of the rotor for selecting an initial commutation state for commanding the spindle motor driver to initiate a spin-up commutation sequence starting from the selected initial commutation state such that the voltage is sequentially applied across a selected combination of the windings in order to spin-up the spindle motor to an operating spin-rate.

Disk drive employing method of spinning up spindle motor including detecting BEMF polarity change for selecting initial commutation state

A disk drive employs a method of operating a spindle motor to respond to a spin-down command to reduce the time required for subsequently responding to a spin-up command. After receiving the spin-down command, and while the rotor continues to spin in the forward-spin direction, a state machine is set to and maintained in a first predetermined register state such that a controlled rotor-stopping operation is performed. At the end of the controlled rotor-stopping operation, the rotor angle is within the range of a peaked forward direction waveform for a second predetermined register state of the state machine.

Growing community of inventors

Mission Viejo, CA, United States of America

Carl R Messenger