DIGITAL PROCESSOR CONTROLLED METHOD AND CIRCUIT FOR RETRACTING A HEAD CARRIAGE ASSEMBLY TO A PARKED POSITION IN A MASS DATA STORAGE DEVICE, OR THE LIKE, BY ACTIVELY DETECTING A DESIRED VELOCITY

摘要

In a method and circuit for retracting a data transducer carrying assembly (17) in a mass data storage device (10), has the assembly (17) is positioned in response to a voltage applied to a driver mechanism (22), and a crash-stop barrier (21) against which the assembly (17) contacts when the assembly (17) is moved to the retract position (23). When a retract process is initiated, a determination is made whether the assembly (17) has contacted the crash-stop barrier (21). If the determination establishes that the assembly (17) has contacted the crash-stop barrier (21), the retract process is terminated. Determining whether the assembly (17) has contacted the crash-stop barrier (21) may be performed, for example, by determining an instantaneous direction of movement of the assembly (17), which may be determined by determining a sign change in the velocity measurements of the assembly (17).