Dynamic Measurement of a Head-Disk Spacing Variation for High Density FDD.

A head-disk interface (HDI) analyzer for a highdensity FDD was improved. This equipment consists of a high-speed shutter camera and a highly sensitive image processor. It makesit possible to evaluate dynamic spacing fluctuations by analysis of interference fringe patterns on both sides of a floppy disk (FD). With this equipment, the dynamic motions of an up-head slider and FD were observed. Moreover, it was shown that the surface roughness of the FD affected the head-touch and that a smoother disk surface caused larger spacing variation. This result indicates that an appropriate surface roughness is required in a FD so as to maintain reliability in a high-density FDD.