Magnetic head control capable of avoidance media bumps during seeking process
AssigneesKabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
InventorsTetsuo Kuribayashi, Hironori Kanno, Masami Tashiro
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Abstract
According to one embodiment, a magnetic disk drive selects in command evaluation in reordering processing, a command accessible in a shortest time. The device determines whether media bumps which influence a dynamic flying height (DFH) control exist in a seek section between completion of a previous command and start of a selected command or not, calculates a latency necessary for avoidance of the media bumps if it is determined by the determination that the media bumps which influence the DFH control exist, and selects the command accessible in the shortest time including the time obtained by summing the latency calculated by the calculation as the command to be next processed.
Claims14
A magnetic disk drive comprising:
- a selector selecting a plurality of evaluation commands in order in a command reordering operation;
- a determiner determining whether media bumps which influence a dynamic flying height (DFH) control exist in a seek section between completion of a previous command and start of a selected evaluation command or not;
- and
- a calculator calculating a delay time necessary for avoidance of the media bumps if it is determined by the determiner that the media bumps which influence the dynamic flying height (DFH) control exist;
- wherein
- the reordering operation compares a latency time which is obtained by summing a seek time which is determined in accordance with a seek distance, a rotational latency time which is determined after a seek completion and the delay time of each of a plurality of evaluation commands, and selects the evaluation command of the shortest latency time as the command to be next processed.
A magnetic disk control method of a magnetic disk drive comprising:
- a selecting a plurality of evaluation commands in order in a command reordering operation;
- determining whether media bumps which influence a dynamic flying height (DFH) control exist in a seek section between completion of a previous command and start of a selected evaluation command or not;
- calculating a delay time necessary for avoidance of the media bumps if it is determined by the determination that the media bumps which influence the dynamic flying height (DFH) control exist;
- comparing the latency time which is obtained by summing a seek time which is determined in accordance with a seek distance, a rotational latency time which is determined after a seek completion and the delay time of each of a plurality of evaluation commands;
- selecting the evaluation command of the shortest latency time as the command to be next processed.
Dependencies are inferred from the claim text.