The present invention is directed to a method and apparatus for performing seek
operations in a disk drive having a disk surface with spiral servo information
written thereon. In one embodiment, a disk surface is provided with a read head
associated therewith. The disk surface has spiral servo information written thereon.
The read head generates a read signal envelope when reading the spiral servo information.
A plurality of integration windows is provided. The plurality of integration windows
have a standard interval therebetween. A position error signal is generated based
upon a location of a read signal envelope within an integration window. The interval
between adjacent integration windows is adjusted from the standard interval to
generate a position error signal. The read head is moved in a radial direction
based upon the position error signal. This process may be repeated to seek across
the disk surface.