Patent ID: 8040630

Claim:
A hard disk drive, comprising: a disk base; a spindle motor mounted on said disk base and coupled to at least one disk to create at least one rotating disk surface containing at least one track with multiple sectors each including a servo address mark; a voice coil motor pivotably mounted to said disk base to position via a head gimbal assembly to at least one slider near said track on said rotating disk surface; and a processor receiving said servo address marks to create a servo address mark delay used to create a touchdown flag in response to said servo address mark delay increasing due to said slider contacting said rotating disk surface; wherein said processor creates said touchdown flag in response to said servo address mark delay increasing and in response to said track having a track location away from an Inside Diameter of said rotating disk surface; and wherein said processor receives a resistive heater electrical reading from at least one resistive heater coupled to said slider that is used to create said touchdown flag in response to said track location being near said Inside Diameter of said rotating disk surface and in response to an electrical reading of said resistive heater increasing when said slider contacts said rotating disk surface.