Patent ID: 6987639

Claim:
A disk drive comprising: (a) a disk comprising a plurality of tracks; (b) a head; (c) a voice coil motor (VCM) for actuating the head over the disk; (d) a command queue for storing a plurality of disk access commands; and (e) a disk controller for executing a rotational position optimization (RPO) algorithm to select a disk access command from the command queue as the next command to execute relative to an estimated seek time required to seek the head to a target track for each command in the command queue, wherein: the disk controller estimates a motor capability of the VCM by measuring a velocity of the VCM relative to a current flowing through the VCM; the disk controller modifies the estimated seek time for each command in the command queue in response to the estimated motor capability; and the disk controller executes the RPO algorithm using the modified estimated seek times.