Simple method of protecting customer data on hard drives returned from the field

A unique identification number is stored in the electronic card that is attached to a disk drive, as well as in a reserved location on the disk itself. This ID number is initialized at head-disk assembly and a match between the two ID numbers is necessary for access to the data on the disk, although not for repairs to the mechanisms themselves. When a disk containing sensitive data is to be removed from a customer site, a technician briefly removes the disk and applies a jumper to specific contacts on the drive, then reinserts the drive and powers it up. This causes the ID on the electronic card to be erased, rendering the data on the drive unreadable. When the drive reaches a repair facility, the erased ID number ensures that the disk will be reformatted before being reused.