Hard Disk Quality and Reliability Features

Hard disk manufacturers recognize the great importance of their customers' data, and therefore, the importance of the quality and reliability of their hard disk drives. In addition to generally improving the quality of their processes and their products, most manufacturers have added special features to their hard disks to help enhance their reliability. Most of these efforts are predicated on the principle that "an ounce of prevention equals a pound of cure". They are intended to either reduce the chances of a problem occurring, or at least let the user know if a problem is likely to occur, before data loss happens.

This chart shows several sample shock events that can affect hard disks,
mapped based on their duration and intensity. Notice that the more serious
shocks are those delivered to the drive by itself, while those caused to the
PC as a whole are less critical to the disk. Modern drives are equipped
with many reliability features that can reduce the likelihood of damage in
the event of common shock occurrences, but no advances will protect
adequately against outright abuse of such delicate hardware. (Not all of
the more serious shock events above will necessarily cause the drive to
fail or data to be lost, but they do definitely carry the potential.)

Image � Quantum Corporation
Image used with permission.

In this section I describe in detail the more common features being implemented on today's drives to enhance their quality and reliability, and to provide warning to the user if a hardware failure is imminent.