READBACK SIGNAL DECREASE DUE TO DYNAMIC LOAD HEAD-DISK CONTACTS

The effect of head-disk impacts due to repeated dynamic load is invest igated experimentally. Loading conditions more severe than those typic ally found in ramp-lend disk drives are applied to ensure that contact s occur, and disk-synchronized head loading motions are applied so tha t the head-disk contact points are all distributed within a small area on the disk. The resulting readback signal decrease was observed to c orrelate with the head-disk impact velocity and hence the slider's ver tical approaching velocity. With a larger vertical velocity readback s ignal decrease appeared earlier and the amount of decrease was larger The results indicate that dynamic load-unload should be quite reliable under typical lending conditions, and the reliability of dynamic load -unload can be achieved by controlling the vertical approaching veloci ty of the slider. This is comparatively easier than controlling the na rrow manufacturing tolerances of the slider's pitch and roll of the he ad-suspension assembly. The technological trend toward using smaller-s ized head-suspension assemblies and higher-coercivity magnetic disks m ay further enhance the dynamic load head-disk interface durability.