Patent ID: 7124625

Claim:
A glide-height disk tester comprising: a rotatable disk having a generally smooth disk surface with a plurality of asperities projecting from the disk surface; a motor for rotating the disk at a generally constant speed about an axis substantially perpendicular to the disk surface; a slider having a front end upstream of the air-flow induced from the disk when the disk is rotating, a trailing end downstream from the front end, an air-bearing surface between the front and trailing ends and facing the disk surface, and a protrusion pad at the trailing end and movable toward the disk surface in response to the application of heat; a contact sensor on the slider for detecting contact of the protrusion pad with an asperity when the disk is rotating at said constant speed; and electrical circuitry coupled to the trailing end of the slider for applying current to the trailing end to resistively heat the protrusion pad while the disk is rotating at said constant speed, the level of applied current determining the amount of movement of the protrusion pad toward the disk surface.