Hard disk Architecture:

A hard disk drive having the platters and motor hub removed indicating the copper colored stator coils surrounding a bearing at the center of the spindle motor. The orange color stripe along the side of the arm is a thin printed-circuit cable. The spindle bearing is in the center of the drive.

A typical hard drive has 2 electric motors, 1 to spin the disks and 1 to position the read and write head assembly. The disk motor has an external rotor related to the platters; the stator windings are fixed in place. The actuator has a read and writes head under the tip of its very ending (near center); a thin printed-circuit cable attached the read-write head to the hub of the actuator. A flexible, somewhat 'U'-shaped, ribbon cable, shown edge-on below and to the left of the actuator arm in the first image and more clearly in the second image, continues the connection from the head to the controller board on the opposite side.