Maxtor Corporation

Esgw Holdings Limited

Jim Hargarten

Thomas O Melrose

John Charles Purkett

Dave Finamore

Scott E Chase

Andy Ottele

Doug Frisby

Gary Counts

a seek procedure for a hard disk drive which provides a significant reduction in acoustic noise as well as high performance fast seek times is described. The seek procedure lowers the peak acceleration for short seeks and imparts a smooth transition from a sine seek to an exponential arrival at the target track. The seek procedure provides an error free feedforward signal derived from a single sine table. The procedure which contains a time domain sinusoid acceleration feedforward combined with a phase-plane trajectory controlled velocity which, near seek completion. The procedure is constructed so that the acceleration begins at zero and, in the fashion of a sine, increases to a maximum, decreases to a minimum and then increases again until a computed switchpoint is reached. The switchpoint is determined in-situ, to provide a smooth and continuous velocity transition from sinusoid to exponential. The velocity trajectory is computed from a look-up table. The procedure is implemented using conventional seek controller servo components and commercially available operation software.

Quiet high performance seek procedure for disk drives

A method and apparatus for automatically determining an embedded runout correction threshold for a disk drive are disclosed. In prior systems, embedded runout correction thresholds were set for all disk drives in a production run. The present invention provides a technique for automatically determining an embedded runout correction threshold on a drive-by-drive basis, instead of a production run of drives basis.

Method and apparatus for automatically determining an embedded runout correction threshold

A method and apparatus for the enhancement of embedded runout correction in a disk drive is provided. According to the present invention, embedded runout correction values are obtained by convolving a position error signal due to repeatable runout for a track with an inverse impulse response describing the response of a transducer head servo system to a given input. According to the present invention, the inverse impulse response is determined by introducing an impulse to a transducer head servo system, and measuring the response of the system in the time domain. The response is transformed to the frequency domain to form an error transfer function, the reciprocal is taken, and the function is transformed back into the time domain. The inverse impulse response, according to the present invention, is obtained for at least every transducer head in a disk drive capable of addressing a track for which embedded runout correction is desired. The embedded runout correction values may be calculated without the use of a servo track writer.

Method and apparatus for the enhancement of embedded runout correction in a disk drive

An actuator control loop for controlling head position in a rotating media data storage system. The invention applies the compensation zero to the PES prior to summing it with the integrator. This scheme reduces transients caused by the integrator initialization step because the zero does not 'see' the integrator initialization step. Transients that can result from coupling the integrator initialization to the zero can cause overshoot and ringing in the actuator, increasing settling time and reducing system performance. The present invention also provides a first sample velocity compensation scheme that removes the velocity correction factor from the PES signal in the first sample after a seek. This significantly reduces settling time and improves system performance. In one embodiment, the microprocessor of the present invention calculates a velocity compensation factor based on the PES signal. This signal is then superimposed on the integrator output. In another embodiment, the zero is moved during the first sample after a seek, so that no velocity correction is undertaken. In subsequent sample periods, the zero is returned to its desired frequency.

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Lafayette, CO, United States of America

Jim Hargarten