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in2 Recording Areal Density on Strontium Ferrite Tape
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  • Mark Lantz ,
  • Simeon Furrer ,
  • Patrick Ebermann ,
  • Hugo Rothuizen ,
  • Walter Haeberle ,
  • Giovanni Cherubini ,
  • Roy D. Cideciyan ,
  • Shinji Tsujimoto ,
  • Yoshihiro Sawayashiki ,
  • Yuto Murata ,
  • Tomohide Ueyama ,
  • Yoichi Akano ,
  • Tetsuya Kaneko ,
  • Hodaka Suzuki ,
  • Masashi Shirata ,
  • Kenji Naoi ,
  • Takashi Koike ,
  • Hiroaki Doshita ,
  • Noriko Imaoka
Mark Lantz
IBM Research

Corresponding Author:[email protected]

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Simeon Furrer
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Patrick Ebermann
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Hugo Rothuizen
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Walter Haeberle
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Giovanni Cherubini
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Roy D. Cideciyan
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Shinji Tsujimoto
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Yoshihiro Sawayashiki
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Yuto Murata
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Tomohide Ueyama
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Yoichi Akano
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Tetsuya Kaneko
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Hodaka Suzuki
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Masashi Shirata
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Kenji Naoi
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Takashi Koike
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Hiroaki Doshita
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Noriko Imaoka
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Abstract

The recording performance of a new prototype magnetic tape based on perpendicularly oriented strontium ferrite particles is investigated using a 29 nm wide tunneling magnetoresistive reader. At a linear density of 702 kbpi, a post-detection byte-error rate of 2.8e-2 is demonstrated based on measured recording data and a software read channel. The read channel uses a 64-state implementation of an extended version of a data-dependent noise-predictive maximum-likelihood detection scheme that tracks the first and second order statistics of the data-dependent noise. At the demonstrated post-detection byte-error rate, a post-error-correction-coding byte-error rate of less than 1e-20 can be achieved using an iterative decoding architecture. To facilitate aggressive track-density scaling, we made multiple advances in the area of track following. First, we developed a new timing-based servo pattern and implemented a novel quad channel averaging scheme. Second, we developed a new field programmable gate array prototyping platform to enable the implementation of quad channel averaging. Third, we enhanced our low disturbance tape transport with a pair of 20 mm diameter air bearing tape guides and a prototype track-following actuator. Fourth, we developed a novel low friction tape head and finally, we designed a set of tape speed optimized track-following controllers using the model-based H∞ design framework. Combining these technologies, we achieved a position error signal (PES) characterized by a standard deviation ≤ 3.18 nm over a tape speed range of 1.2 to 4.1 m/s. This magnitude of PES in combination with a 29 nm wide reader enables reliable recording at a track width of 56.2 nm corresponding to a track density of 451.9 ktpi, for an equivalent areal density of 317.3 Gb/in2.