An access performance adjusting method is adapted to a storage apparatus
having a storage to prestore a skew quantity that is used to shift a data
write starting position of each track of a recording medium depending on
a head moving time required to move a head from one track to another
track during a sequential access in which a plurality of tracks of the
recording medium are accessed sequentially. The method includes measuring
an apparatus performance with respect to a combination of the head and
the recording medium, calculating a skew adjusting quantity with respect
to the combination based on a reference apparatus performance and the
measured apparatus performance, and adjusting the skew quantity read from
the storage by the skew adjusting quantity and storing the adjusted skew
quantity in the storage as an updated value of the skew quantity.