Read-Back Schemes for Two-Dimensional Magnetic Recording

Abstract

This paper involves the pursuit of an optimal array of read-back heads for improved track resolution in the presence of inter-track interference for high-density magnetic media, moving towards 10 Terabits in:2 (10×10 in: 12 2 bits). The current state of magnetic recording (MR) research is discussed through a brief history of the MR industry and the many issues that have arisen, focusing on inter-symbol and inter-track interference during the read-back process. Recent solutions to these issues include the implementation of signal processing and perpendicular MR. For high densities, an array of three read-back heads in coordination with two-dimensional signal processing is optimized for track resolution using minimum-mean square error, bit-error rate, and cross-correlation for six different theoretical head geometries. Using the reciprocity principle, optimal physical spacing of read-back heads and signal combinations were concluded in an ideal media environment. Optimal schemes were then applied to a realistic, non-linear medium to determine industrial feasibility. Conclusions suggest that further work is required to re-optimize schemes using realistic Voronoi grains. Overall, it is known that the determined optimal read-back schemes improve resolution of written media and may allow for further improvement and industrial application in the coming years.