Abstract: In the present invention, a single sector counter and accompanying multiple buffer registers are used to provide the sector count for a plurality of recording zones. Initially, the sector counter is validated by synchronizing it with an index mark. In one embodiment, an angular position sensing counter counts a clock having a frequency and phase to match the occurrence of segments in a reference zone. A look up table or computation provides an offset value representing the difference between each reference zone segment boundary, and the occurrence of the next consecutive sector in each of the recording zones. Additional logic generates periodic sector pulses once the zone transition has been accomplished, and provides means to prevent generation of shortened sector intervals. This permits rapid validation of the sector signal so that it is no longer necessary to wait for the index in a hard-sectored drive before establishing the sector position when changing zones.

Abstract: In a hard disk drive memory, a device for controlling a seek operation in which the head is gradually accelerated, then gradually decelerated to move the head quickly from one track to another. The head detects the current track position and triggers a "seek profile" based on the distance of the destination track whereby the device determines the ideal acceleration curve for the seek to be performed. From this, the head begins the seek over a series of consecutive time segments, monitoring its position and determining nominal position at the end of the next successive time segment. In this way the seek profile is updated at each small time segment. Thus, the final head placement is more accurate than in conventional art, in which only an initial distance estimate is used to guide the placement of head. The gradual acceleration/deceleration of the head reduces noise and system wear compared with the full-power acceleration/deceleration utilized in the prior art.