Head crash

[2] The disk read-and-write head is made using thin film techniques that include materials hard enough to scratch through the protective layers.

After this initial crash, countless numbers of fine particles from the damaged area can land on other areas and can cause more head crashes when the heads move over those particles, quickly causing significant damage and data loss, and rendering the drive useless.

Some modern hard disks incorporate free fall sensors to offer protection against head crashes caused by accidentally dropping the drive.

However, since in many cases, the medium was housed in a removable cartridge or pack and since air filtration was comparatively crude, crashes were fairly frequent and invariably expensive.

This has led to the development of protective technologies that "park" the head at a safe distance from the disk when sudden motion, such as that of a dropped computer, is detected.