In devices with a moving coil there are no pre-fixed positions. Instead, they use a special guidance system (positioning), which accurately brings the heads to the desired track.
The system of precise guidance of the heads on the tracks is called a servo drive, and for its operation a feedback signal is required that carries information about the real relative position of the tracks and heads.
Temperature fluctuations do not affect the accuracy of the drive. When compressing and expanding disks (rotation, temperature), all changes in their sizes are monitored by a servo drive and the positions of the heads are adjusted. Continue reading