The following examples illustrate typical damage caused by water. Note the surface corrosion on the case and actuator. Although the platters appear to be in good condition to the naked eye, microscopic pitting is often present.

  Media Failure:

The dull ring visible near the hub (see below) is an example of media failure. This type of damage is typically caused by contaminants in the drive enclosure, or from the read/write heads coming in physical contact with the platter. Normally, the read/write head is suspended above the platter on a thin cushion of air. Overheating can sometimes cause this type of damage due to the reduced viscosity of the air cushion between the head and platter.

  Acute Media Failure:

Below is an acute form of media failure. Note the platter damage visible to the right of the hub in the band where surface contaminants have been removed. Also note the jagged wear patterns near the hub, which was caused by chattering. Damage to this degree results from prolonged operation of the drive after the initial failure; such as a failure occurring on an unattended server, or from repeated non-professional attempts to recover data. This drive is beyond recovery.

  Also See:

Examples of Fire Damage.