A hard disk drive with a circuit that provides a current to a voice coil motor to move a head over a disk in a seek routine. The disk has track boundaries with discontinuities in track addresses. The circuit includes a state estimator that predicts a next state of the head. The state estimator sets an estimation error to zero when the head is over one of the track boundaries. The estimator then computes a predicted position that is used in a feed forward servo loop to generate a drive current. The drive current is provided to the voice coil motor to move the head across the disk.