The invention is directed to methods and apparatus for repositioning a
data storage disc on a spindle assembly, to reduce eccentricity of data
on the disc. The eccentricity can be identified and be reduced
automatically by determining the magnitude and direction of an
eccentricity vector that representing a misalignment of a central point
around which the data are arranged on a data storage disk with an axis of
a spindle, and moving the disc so that the eccentricity vector is
reduced. One technique for moving the disc is to push the edge of the
disc so that the central point moves closer to the axis of the spindle.