Media surface finish considerations for magnetic recording with 3380 type sliders

A method is proposed for determining sufficient surface finish specifications for rigid magnetic disks. This method is based upon a maximum allowable deviation in the average amplitude of the playback signal envelope. Disk surface asperities were modelled as superposed high and low frequency continuous sine functions and single cycle sine functions with frequencies between 1 kHz and 100 kHz. An illustrative example of playback with a 3380 type slider was demonstrated. The slider-disk air lubrication problem was solved by a numerical solution to the Reynolds Equation with slip-flow boundary conditions. Results of analyses showed that any surface finish specification is a trade-off between the amplitudes of the low and high frequency components of the surface asperities.