A system comprises a positioning module, a frequency measuring module, a
simulation module, and a control module. The positioning module positions
an actuator arm adjacent to a track to read spirals that are prewritten
using current of a predetermined frequency. The frequency measuring
module measures a first frequency of sync marks of the spirals when the
actuator arm is positioned adjacent to the track. The simulation module
calculates a second frequency of the sync marks when the actuator arm
moves at a predetermined actuator velocity. The control module calculates
an actuator velocity at which the spirals are prewritten based on the
first frequency, the second frequency, and the predetermined actuator
velocity.