An experimental comparison of the head/disk interface dynamics in 5¼- and 8-inch disk drives

A laser Doppler vibrometer is used to measure the head/disk interface dynamics in computer disk drives. The stability of the head under steady operating conditions is compared between a 5¼-inch and two different 8-inch “Winchester” drives. In the larger drives, high-frequency vibrations (between 5 and 10 kHz) are detected on the slider which are not present in the smaller drive. These vibrations have amplitudes on the order of magnitude of the head/disk spacing and are related to the rolling and pitching modes of the slider. The vibrations of the disk, suspension, and actuator arm are also investigated and correlated with the results obtained on the slider.