Most of the digital information in the whole world is stored on the desktop hard drives. When a mechanical shock happens, hard drives may experience damage caused by the read/write heads dropping down onto the moving platters. Normally these heads float on a thin layer of air over the spinning platters, but if a shock happens and the two do come in direct contact, the heads can literally become “glued” to the plates. When this does happen, the heads can only be “unglued” from the plates by a trained engineer using special equipment.