| 摘要 |
A system and method that utilize a scheduling algorithm to profile the seek operation of an I/O command based on its available rotational time, for improving the average command access time and hence the disk drive throughput. The seek profile of a command is adjusted so that the seek operation is performed in a servo dual mode: a conservative mode at a slower seek velocity, and an aggressive mode at a higher seek velocity. The scheduling algorithm reorders the I/O commands based on the seek length from the current command to the next command, and on the rotational distance that reflects the rotational time. If the rotational time for a particular command is long relative to its seek length, the seek operation is performed in the conservative mode with a very high probability of success within the available time. If, however, the rotational time for a particular command is short relative to its seek length, whereby the conservative mode is expected to require an additional revolution, the seek operation is performed in the aggressive mode with a significant probability of success within the available rotational time. In the event of a resulting miss, a revolution will be added to the rotational time. This dual servo increases the overall probability of success of the seek operation, resulting in a smaller average access time and thereby a higher throughput of the disk drive.
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