The Structure of Shingled Magnetic Recording Tracks

Abstract

The use of a wider writing shingled magnetic recording (SMR) head in spinstand experiments allowed different regions of the SMR track to be analyzed and described. Here, we break the track into curved, best, and trimmed areas. The curved area is written with the writer edge, which has high curvature and poor write field gradient, resulting in low resolution and high noise. The trimmed region is defined by head fields combining with disk demagnetization fields. Together these fields attack the low frequency magnets, boosting resolution, increasing noise, and generating a narrow out of phase copy of the trimmed track (the negative sliver). This is explained via measurements and modeling. We also explain the measured magnetic write width dependence on linear density based on the frequency response of the reader as well as writer and media effects. We employ linear deconvolution to extract the binary impulse responses of the SMR data track and its neighboring tracks to characterize intertrack interference. The writer and media effects, which give rise to the negative sliver observed, are shown to explain the interference behavior with linear density.