The current technology of the computer hard disk is a mixture and refinement of record player and tape recorder technologies.
The disks spin around just like a record would and they are coated with magnetic material like tape recorder tape. The heads follow magnetic tracks like the needle on a record player follows grooves in a record. The heads are on the end of an arm, much like the tone arm of a record player. The magnetic tracks are microscopic allowing gigabytes of data storage. Drives spin their disks at 7200 rpm and are sealed to avoid dust particles.
The heads however are moved in and out with a voice coil actuator. The heads themselves are microscopic and require an amplifier to boost their signal. They are so small that a dust particle could destroy them.
The voice coil actuator consists of the arm which holds the heads, a bearing to turn on, a wire coil and two strong magnets.
The controler board is the brains of the hard drive it controls are of functions and interfaces the drive with the computer.