Failure mechanisms of the head-tape interface during head stepping in a linear tape drive

Abstract

Improving the performance of computer tape drives is an ongoing process. The magnetic and tribological performance of metal particle (MP) tape during head stepping was evaluated in a commercial linear tape drive. Head output and head-tape interface friction were monitored during short-pass (10m) shuttling tests with stepping of the head. The test without stepping showed no signs of failure. To evaluate the effect of stepping on the head-tape interface, three different kinds of stepping test, namely normal stepping, reverse stepping and normal stepping with inverted drive, were performed. All these tests with head stepping failed far sooner than the test without stepping. Non-parallelism between the head and tape surfaces caused a reduction in hydrodynamic air bearing pressure. Less spacing between the lower tape edge and the head resulted in high wear of the lower edge of the tape and outer outrigger surfaces of the head. Additional sliding in a direction orthogonal to the tape motion from head stepping aggravated the friction and wear of the lower tape edge. The inability of the drive to overcome this high friction ultimately resulted in failure. On the head surface, different kinds of debris were found, and unsymmetrical debris distribution was observed. Some manufacturing improvements are presented to prolong drive durability.