Disk drive employing a multi-phase rotational position optimization (RPO) algorithm
AssigneeWestern Digital Technologies, Inc.
InventorGregory B. Thelin
Life of this patent
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Abstract
A disk drive is disclosed which executes a rotational position optimization (RPO) algorithm for selecting a next command to execute out of a plurality of pending commands. The RPO algorithm comprises a first phase and a second phase. The first phase of the RPO algorithm is executed relative to a first priority and in response to at least one non-real-time parameter. The second phase of the RPO algorithm is executed relative to a second priority higher than the first priority and in response to at least one real-time parameter.
Claims12
A disk drive comprising:
- (a) a disk;
- (b) a head actuated radially over the disk;
- and
- (c) a disk controller for executing a rotational position optimization (RPO) algorithm for selecting a next command to execute out of a plurality of pending commands, wherein:
- the RPO algorithm comprises a first phase and a second phase;
- the first phase of the RPO algorithm is executed relative to a first priority to compute a seek latency and a rotational latency for at least one of the pending commands in response to at least one non-real-time parameter;
- and
- the second phase of the RPO algorithm is executed relative to a second priority higher than the first priority to update at least one of the seek latency and the rotational latency for the at least one pending command in response to at least one real-time parameter.
A method of executing a rotational position optimization (RPO) algorithm in a disk drive for selecting a next command to execute out of a plurality of pending commands, the disk drive comprising a disk and a head actuated radially over the disk, and the RPO algorithm comprising a first phase and a second phase, the method comprising the steps of:
- executing the first phase of the RPO algorithm relative to a first priority to compute a seek latency and a rotational latency for at least one of the pending commands in response to at least one non-real-time parameter;
- and
- executing the second phase of the RPO algorithm relative to a second priority higher than the first priority to update at least one of the seek latency and the rotational latency for the at least one pending command in response to at least one real-time parameter.
A disk drive comprising:
- (a) a disk;
- (b) a head actuated radially over the disk;
- (c) a plurality of allocation state queues for storing commands comprising cache segments;
- (d) a plurality of allocation states comprising:
- an available allocation state indicating an allocated cache segment storing write data that has been written to the disk;
- a valid allocation state indicating an allocated cache segment storing cached read data;
- and
- a dirty allocation state indicating an allocated cache segment storing write data not vet written to the disk;
- and
- (e) a disk controller for executing a rotational position optimization (RPO) algorithm for selecting a next command to execute out of a plurality of pending commands, wherein:
- the RPO algorithm comprises a first phase and a second phase;
- the first phase of the RPO algorithm is executed relative to a first priority and in response to at least one non-real-time parameter;
- the second phase of the RPO algorithm is executed relative to a second priority higher than the first priority and in response to at least one real-time parameter;
- and
- the non-real time parameter comprises at least one of the allocation states.
A method of executing a rotational position optimization (RPO) algorithm in a disk drive for selecting a next command to execute out of a plurality of pending commands, the disk drive comprising a disk and a head actuated radially over the disk, a plurality of allocation state queues for storing commands comprising cache segments, and a plurality of allocation states comprising:
- an available allocation state indicating an allocated cache segment storing write data that has been written to the disk;
- a valid allocation state indicating an allocated cache segment storing cached read data;
- and
- a dirty allocation state indicating an allocated cache segment storing write data not yet written to the disk;
- the RPO algorithm comprising a first phase and a second phase, the method comprising the steps of:
- executing the first phase of the RPO algorithm relative to a first priority and in response to at least one non-real-time parameter;
- and
- executing the second phase of the RPO algorithm relative to a second priority higher than the first priority and in response to at least one real-time parameter, wherein the non-real time parameter comprises at least one of the allocation states.
Dependencies are inferred from the claim text.