Simulation of the head disk interface for discrete track media

Abstract

This paper investigates the effect of discrete tracks on the steady state flying behavior of sub ambient proximity sliders. A finite element based air bearing simulator is used to simulate the flying characteristics of sliders over a grooved disk surface. Sliders flying over discrete track disks ''see'' a disk surface that consists of ridges and grooves. The air bearing pressure build-up for sliders flying over discrete track disks is different from that for sliders flying over plane disks. Low air bearing pressure can be expected for those regions of the slider that are positioned over grooves, while high air bearing pressure exists over ridges. The air bearing characteristics are determined for several pico and femto-type air bearing sliders flying over discrete track disks. An empirical equation is obtained describing the loss of flying height of a slider flying over discrete track disks.

Numerical Simulation of the Head/Disk Interface for Patterned Media

“…2 can be used to predict the change in flying height for small pattern heights and for a ratio of pattern diameter to pattern pitch equal to one half. Duwensee et al [10] obtained an empirical equation that predicts the change in flying height for DTR media as follows [10]:…”

“…3). These slider designs were previously investigated by Duwensee et al [10] for discrete track media. The four femto sliders shown in Fig.…”

“…They determined the pressure distribution for a two-rail, positive pressure slider and observed an increase in the flying height due to surface pattern. In a more recent investigation, Duwensee et al [10] have numerically studied the head/disk interface for DTR. They investigated the effect of groove depth on the flying height and flying attitude for a constant ratio of groove width to groove pitch.…”

“…In areas of higher spacing, a coarser finite element mesh was chosen, since the influence of surface features is decreasing with increasing spacing. The numerical approach is similar to that used by Duwensee et al [10] in the study of the head/disk interface for discrete track media. Finally, the flying height change due to bit pattern is compared with the results for DTR [10].…”

“…The numerical approach is similar to that used by Duwensee et al [10] in the study of the head/disk interface for discrete track media. Finally, the flying height change due to bit pattern is compared with the results for DTR [10]. Figure 1 shows the transfer of the bit pattern from the disk surface to the slider ABS.…”