Abstract: A digital servo control system in a data recording disk file has a single processor which generates the control signal to the actuator at two different rates, depending on whether the read/write head is being moved between data tracks or is following a specific track. A sampling clock generator receives servo timing information from a recorded servo disk surface and generates interrupt signals to the processor at predetermined frequencies selected by the time required for the processor to run the algorithm which generates the control signals. Upon receipt of a seek command to move the head of a target track, or a predetermined head position error signal indicative of arrival of the head to the target track, the microprocessor enables or disables appropriate interrupts so as to select one of the appropriate rates for generating the control signals. The digital servo control system thus allows servo position information to be sampled at a higher frequency during track following.

Abstract: A data recording disk file with a voice coil motor (VCM) actuator and a digital servo control system for positioning the read/write heads to selected concentric data tracks includes means for calculating the factor relating acceleration of the heads to VCM input current. This permits each disk file to compensate for any variation in the nominal VCM physical parameters, thus enabling VCMs to be manufactured to less demanding tolerances. The disk file also calculates a unique acceleration factor for each head position during movement of the heads from one track to another, thereby improving the arrival time of the heads to the target track. During an initialization procedure, the disk file performs a track seek, during which VCM current and head velocity information are acquired and used by the microprocessor in the digital servo control system to calculate a value representing an average actual acceleration factor unique to that disk file.