Scott E. Ryun

Entropy-Based Multi-Resolution Head/Media Contact Detection for Hard Disk Drive

A double entropy-based characterization methodology is proposed for the hard disk drive (HDD) head/media contact detection operation. At first, signal entropy minimization is used to extract the head/media modulation-induced proximity sensor response converting it into four compact and descriptive parameters derived from an adaptive discrete wavelet transform (ADWT). The second stage and the head/media contact decision process involve statistical screening of moving entropies derived from the four ADWT parameters. This double entropy methodology provides significantly improved head/media contact decision fidelity and targets modern HDD products.