Glide head with an outside active rail

A method of testing the surface of a memory disk for defects, said method comprising:

• placing a glide head over said surface, said glide head comprising a slider and a transducer mounted to said slider, said slider having a trailing end and an air bearing surface, wherein said slider comprises an inside rail extending downwardly from said air bearing surface, said inside rail having a trailing end located toward said trailing end of said slider, said slider further comprising an outside rail extending downwardly from said air bearing surface, said outside rail having a trailing end located toward said trailing end of said slider, wherein said trailing end of said outside rail extends further in the direction of said trailing end of said slider than said trailing end of said inside rail whereby said outside rail generates a greater amount of mechanical energy than said inside rail from encountering at least one of an asperity, contamination, and a void on said magnetic disk;
• providing a relative motion between said surface of said magnetic disk and said glide head;
• said transducer sensing mechanical energy when said glide head encounters at least one of an asperity, contamination, and void on said magnetic disk;
• said transducer converting said mechanical energy into an output signal;
• and
• monitoring said output signal from said transducer.

A glide head to detect defects on a disk substrate, said glide head having a leading end, and trailing end, and an air bearing surface, said glide head comprising:

• an inside rail extending downwardly from said air bearing surface, said inside rail having a leading end located toward said leading end of said glide head and a trailing end located toward said trailing end of said glide head;
• an outside rail extending downwardly from said air bearing surface, said outside rail having a leading end located toward said leading end of said glide head and a trailing end located toward said trailing end of said glide head, said trailing end of said outside rail extending further in the direction of said trailing end of said glide head than said trailing end of said inside rail, wherein said outside rail generates a greater amount of mechanical energy than said inside rail from encountering at least one of an asperity, contamination, and a void;
• and
• means for determining when said glide head encounters one of at least an asperity, contamination, and void on a disk substrate.

A glide head for testing a rotating media, said glide head having a top surface, a bottom surface, a leading end and a trailing end, said glide head comprising:

• a first rail on said bottom surface, said first rail having a first length;
• a second rail on said bottom surface, said second rail having a second length, wherein said first length is greater than said second length, said first rail extending fuither towards said trailing end of said glide head than said second rail;
• a taper on the leading end of said first rail and said second rail for providing lift on said leading end of said glide head, wherein said trailing end of said glide head flies closer to said rotating media than said leading end, the trailing end of said first rail flies closer to said rotating media than the trailing end of said second rail such that a defect contacting said trailing end of said first rail will produce more mechanical energy than said defect contacting said trailing end of said second rail;
• and
• a piezoelectric crystal mounted on said glide head for converting mechanical energy caused by said first rail or said second rail physically contacting said defect into an electric signal.