Inventors:
Adam Michael Espeseth - Rochester MN
David Robison Hall - Rochester MN
James Joseph Mosser - Rochester MN
Steven Glenn Smith - Rochester MN
Assignee:
Hitachi Global Storage Technologies Netherlands B.V. - Amsterdam
International Classification:
G06F 1200
Abstract:
A method and apparatus are provided for hard disk drive command queue ordering. For each command in the hard disk drive command queue, an expected access time is calculated including a probability of success calculation. A command in the hard disk drive command queue having a minimum calculated expected access time is identified. Then the identified command having a minimum calculated expected access time is executed. For an estimated seek time of less than a time for one full revolution, a probability of a miss multiplied by a time of one extra revolution is calculated and the result is added to an estimated seek time to provide the expected access time. For an estimated seek time of greater than a time for one full revolution, a probability of a make multiplied by a time of one extra revolution is calculated and the result is subtracted from an estimated seek time to provide the expected access time.