The magnetic recording industry uses magnetoresistor elements to read information stored on computer disks. The read head is a titanium carbide wafer with a thin-film stripe of magnetoresistive material. As the head sweeps over the disk, variations in the magnetic field from the disk alter the resistance of the stripe, which translates the signal into voltage. As each new design of disk drive increases the density of information on the disk, the magnetoresistor stripe has to be made correspondingly narrower.
Electrostatic discharges pose a variety of threats in addition to melting the magnetoresistor stripe. The current from a discharge can produce a magnetic field that can alter the data recorded on the disk. In disk drives, the disks and heads move at high velocities in extremely close proximity: the system has been compared to flying a fighter jet at 100 feet. A minute blister or nodule produced by ESD can spoil the aerodynamics of this flight and create havoc.