Abstract: Method and apparatus for data security in a data storage device. In some embodiments, a first version of firmware is installed in a memory of the device. The firmware is used by a programmable processor to control accesses to a rotatable data recording medium on which is written pre-recorded servo positioning data used to position a data transducer. A newer, second version of the firmwave is subsequently installed in the memory to replace the first version of firmware. The second version of the firmware includes an instruction to corrupt a selected portion of the servo positioning data on the medium in order to authenticate the second version of the firmware. During a subsequent initialization of the device, host access is granted based on detection of the corruption of the selected portion of the servo positioning data.

Abstract: During the deceleration portion of a seek operation, the current level provided to the actuator motor of a disk drive is based on a desired linear deceleration versus time profile that has been temporally advanced by half of a servo data position sampling interval. At each position sampling interval, a new current level is determined and maintained for the interval between samples. The actual deceleration current follows a staircase curve centered on the desired profile so as to be self-synchronizing. The current level is also adjusted to compensate for the delay between obtaining a new servo data position sample and applying a new current level to the motor.

Abstract: An apparatus for detecting an over-velocity error condition of a head actuator driven by a voice coil motor in a hard disk drive system includes an integrator for providing an integrated value of the current flowing through the voice coil motor and a detector for detecting when the integrated value exceeds a threshold value. In response to this detection, the supply of current through the voice coil motor is interrupted. To prevent false detections, the integrator is inhibited until the motor current reaches a level indicative of a track access operation.

Abstract: A focus initialization system adapted for use with an optical data recording system. Focus initialization is performed while a tracking servo loop is in an open loop mode, and an objective lens is fixedly positioned along a tracking axis. With a focus servo system in an open loop mode, the objective lens is cyclically driven along a focus axis about a neutral position and between offset positions. Displacement of the offset positions from the neutral position is increased with each successive cycle. After the objective lens has been positioned at each peak offset position, the focus servo loop is closed and track crossings resultant from eccentricity of the servo tracks on the record carrier are counted. Focus capture is recognized when at least a predetermined number of track crossings are counted during a predetermined time period.