Optimization of Bit Geometry and Multi-Reader Geometry for Two-Dimensional Magnetic Recording

John R. Barry, Bane Vasic, Mehrdad Khatami, Mohsen Bahrami, Yasuaki Nakamura, Yoshihiro Okamoto, Yasushi Kanai

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


The move from traditional single-track magnetic recording to two-dimensional magnetic recording (TDMR) with squeezed tracks and multiple readers opens up new design degrees of freedom beyond the track pitch and bit-aspect ratio, including the widths, spacing, and crosstrack positions of the readers. In this paper, we present a systematic method for determining the combination of multi-reader geometry, track pitch, and bit-aspect ratio that maximizes the areal density of a TDMR system using single-track detectors. The method combines realistic modeling of the medium and write/read processes, advanced signal detection, and information-theoretic tools. For the particular head and medium we consider, the two-reader geometry that maximizes areal density with zero skew and zero misregistration was found to use different-sized readers (the smaller having a full-width at half-maximum width, i.e., 96% of the track pitch and the larger having a width, i.e., 148% of the track pitch) with significant overlap in the crosstrack direction (centers spaced by one eighth of the track pitch). The optimal bit-aspect ratio was 2.2. At the optimal operating point, the information rate per coded bit is 0.8.

Original languageEnglish (US)
Article number7283623
JournalIEEE Transactions on Magnetics
Issue number2
StatePublished - Feb 2016


  • Two-dimensional magnetic recording
  • data-dependent noise
  • information theory
  • intersymbol interference (ISI)
  • intertrack interference (ITI)
  • shingled magnetic recording

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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