Method and apparatus for predictive failure analysis technique for head crashes in hard drives using position error signal

摘要

A position error signal indicative of the distance between an expected position of a magnetic head relative to the track centerline of a magnetic data storage and retrieval system and an actual position of the magnetic head relative to the track centerline is detected. An absolute value of the position error signal is determined and stored. The detection, determination, and storage is repeated over several revolutions of the magnetic data storage and retrieval system. A maximum of the absolute values of the position error signals is then determined and compared to a threshold value. If the maximum of the absolute values of the position error signals exceeds the threshold value, a warning signal is propagated. An alternative embodiment similarly predicts the possibility of head-disk crash on the basis of the maximum value of several samples of the squares of the position error signals.