A method and apparatus for exactly compensating for a track zero position
when copying a reference servo pattern in a disc drive adopting a
reference servo track copying method. The method of compensating for a
track zero position in a reference servo track copy system for copying a
reference servo pattern in a head disc assembly into which a reference
disc, on which the reference servo pattern is recorded, produced offline
and at least one blank disc are assembled, includes: searching for a
collision position of an actuator arm against a stopper for limiting the
displacement of the actuator arm on the reference servo pattern;
calculating an optimal track zero position based on the searched
collision position; and copying the reference servo pattern on all disc
surfaces from the calculated optimal track zero position.