Mike Suk

Potential data loss due to head/disk contacts during dynamic load/unload

A functioning IBM drive was converted into a component load/unload tester in order to determine the consequence of full-speed loading and unloading of a slider on top of magnetic data. Tests using this apparatus show that the disk scratch damage produced by load/unload is necessary but not sufficient to result in defects that are detectable by surface analysis test. Comparison of the AFM of the scratch damage sites with the MFM of the surrounding data bits shows that data loss results from the physical damage and that any magnetostriction effect is negligible.

Comparison of friction measurement between load/unload ramp and suspension lift tabs using strain gauge and actuator current

Friction force between the load/unload ramp and suspension is measured and compared using two different methods. One method uses a well-known technique utilizing strain gages, which is similar to the method used to measure stiction and friction during contact-start-stop. The other method involves measuring the required actuator current to move the suspension across the load/unload ramp. In this paper we show that the actuator measurement can accurately predict the friction force between the ramp and the suspension on certain regions of the ramp.

A Novel HDD “Component-Level” Operational-Shock Measurement Method

This paper describes and validates a novel experimental method for measuring the operational-shock performance of hard-disk drives, which allows for easy replacement of mechanical components. By nonintrusively instrumenting the hard-disk drive with the ability to measure the dynamic capacitance change between the slider and disk, we are able to obtain slider air-bearing dynamics, slider lift-off, and slider-disk contact during operational-shock events and ultimately failure. We also discuss a complex nonlinear model for accurate simulation of operational-shock events. The experimental data is compared to drive-level data and modeling results for various combinations of mechanical components showing excellent correlation. From this method, we are able to quickly evaluate operational-shock performance of various components on a hard-disk drive level

Production and Performance of

An alternative has been sought for the very hard ceramic material (Al2O3 plus TiC) used as the substrate for magnetic recording heads. We have substituted silicon as the substrate and slider body material; the primary insulator enclosing the recording head was made of SiO2. We built and tested these sliders with full read and write capability in disk drives. Si provides improvement with respect to hardness, modulus, and thermal conductivity, and adds the potential of active electronics located immediately adjacent to the recording head. We describe a novel means of producing heads, using entirely dry etching, rather than diamond sawing. The sliders were etched from the finished wafers in the form of individual sliders, rather than rows of sliders, and were processed individually through to completion. Conventional air bearings were etched into the sliders, suspensions were attached, and drives were built and tested. The outcome shows a profound advantage in the mechanical head/disk interaction, particularly under shock conditions. Other results and slider characterization are described.