Rigid disk drive data reliability in harsh environments

A critical factor in long-term data reliability in a rigid disk drive, namely an accurate head positioning system that can cope with mechanical problems induced by the environment, is examined. It is noted that ensuring reliable data recovery under harsh environments requires the application of new techniques in servo positioning. A way to compensate for many of the errors is to provide some method of position feedback from each data head in addition to the position feedback available from the dedicated servo surface. If a data head misposition relative to its data track can be determined then the appropriate position correction can be applied. Several approaches available to the disk drive designer to provide position feedback from each data head are discussed. The achievement of tolerance to transmitted shock and vibration is also considered