The effects of MR induced non-linearities on channel performance

High performance disk files of today are utilizing magnetoresistive (MR) heads to realize significant improvements in areal density. The MR head is a non-linear device which can at best be operated in a quasi-linear mode. The effect of MR induced non-linearities on the recording channel performance is not widely understood. The partial response channel is known to be sensitive to write non-linearities. In this paper we study the effects of read process non-linearities. We present the results of a combined recording process and channel model to quantify the signal margin reduction of the peak detect channel and the PR4 channel, as a function of various MR induced non-linearities. We find that the traditional measure of MR peak asymmetry is inadequate to predict channel performance.<>