Disk shape and its effect on flyability

The static spacing loss of slider-disk interface is investigated through careful characterization of disk shape for disks of different form factors with different peak-to-valley flatness values. Measured radial profiles are normalized and found to be confined within a relatively narrow region. The representation of these shapes is reduced to a simple set of quadratic equations. Static flyability models associated with the disk radial slope (crown effect) and radial curvature (camber effect) are presented. Spacing loss is calculated for a negative pressure pico-slider and a positive pressure catamaran nano-slider. Results show that slider geometries and crown/camber sensitivity, as well as disk flatness and shape, all affect static slider-disk spacing loss. The analysis is focused on the effect of disk shape on the static spacing loss and its relationship to slider design. Index Terms--Disk drive, disk shape, flatness, flyability.