An information storage system has structure with a head that can effect
information transfers with respect to a storage medium. According to one
feature, a control portion monitors a characteristic of information read
from the storage medium, and can take action to reduce the likelihood of
non-recoverable errors based on the characteristic. According to a
different feature, the control portion moves the head to a position
adjacent a portion of a surface on the storage medium, waits while moving
the head relative to the surface, and then moves the head to another
position adjacent a different portion of the surface. According to
another feature, the control portion calculates a distance of the head
from the surface based on information read from the surface, and
determines based on this distance whether the head or the storage medium
may fail to satisfy a criteria.