Motion of this beam generates an electrical signal in the piezoelectric film covering the beam. The chip then translates mechanical shock into an electrical voltage, with amplitude proportional to the strength of the shock. A comparator circuit monitors the electrical signal generated by the sensor. The write circuit is disabled when the circuit threshold is exceeded. Having temporarily disabled the write operation, recovery time is minimized in order to maintain user productivity.
Recovery is tied to circuit speed, and is therefore in the microsecond range.
Resumption of the write operation is gated by the rotational latency of the spindle. At this time, normal operation resumes and data transfers to the target sector. When a shock occurs during write operation, the potential for data corruption exists. This necessitated a close working relationship between the drive designers and the chip manufacturer. Confirming functionality involved a special test bed.