Data storage device

A data storage device comprising:

• a data recording medium;
• a first light source configured to generate a first laser beam;
• a light application unit configured to split the first laser beam into a first light beam and a second light beam, and apply the first light beam and the second light beam to the data recording medium from different directions;
• a light detection unit configured to detect reflected light beams to generate a detection signal, the reflected light beams corresponding to the first light beam and the second light beam reflected by the data recording medium;
• a light deflection unit arranged in optical paths of the reflected light beams from the data recording medium to the light detection unit, and configured to deflect the reflected light beams to direct the reflected light beams to the light detection unit;
• a arithmetic unit configured to calculate positional error information indicating a relative position and posture of the data recording medium with respect to a target position and posture based on the detection signal;
• and
• a drive unit configured to displace a position and a posture of the data recording medium based on the positional error information.