The mechanical integrity of a thin-film disk drive is determined by co
ntact start-stop (CSS) testing. Poor results in CSS testing are called
either a wear or a stiction failure. Ambiguities are identified betwe
en wear and stiction observations and properties of the head/disk inte
rface that caused the failure. The CSS test results are categorized in
to five wear and stiction regimes that are related to the physical pro
perties of the head/disk interface.