Drive-level flying height measurements and altitude effects

Abstract

Abstraci -An electrical method was developed to measure the flying height in a sealed drive. In this method, componentlevel measurements were first performed on a PPL interferometer and a Guzik tester. Good correlation was found between the flying height and the pulse width (PW50). Within the range of interest, the PW50 was a linear function of the flying height. Thus, the flying height in the drive was obtained by measuring the PW50. This method was used to study the variation in the flying height due to the reduction in air pressure. Changes in recording properties such as signal amplitude, SNR and O W with the altitude change were also studied.