29.5- $\hbox{Gb/in}^{2}$ Recording Areal Density on Barium Ferrite Tape

TLDR: In this paper, the authors used a servo channel and a timing-based servo pattern to generate position estimates with nanoscale resolution at a high update rate, achieving a position-error signal (PES) with a standard deviation of 10.3 nm.

Abstract: The recording performance of a new magnetic tape based on perpendicularly oriented barium ferrite particles was investigated using a 90-nm-wide giant-magnetoresistive reader and a prototype enhanced-field write head. A linear density of 600 kb/in with a postdetection byte-error rate $ was demonstrated based on measured recording data and a software read channel that used a noise-predictive maximum likelihood detection scheme. Using a new iterative decoding architecture, a user bit-error rate of $ can be achieved at this operating point. To facilitate aggressive scaling of the track density, we made several advances in the area of the track-following servo. First, we developed an experimental low-noise tape transport. Second, we implemented an optimized servo channel that together with an experimental timing-based servo pattern enables the generation of position estimates with nanoscale resolution at a high update rate. Third, we developed a field-programmable gate array-based prototyping platform in which we have implemented the servo channel and an $H_{\infty }$ -based track-following controller, enabling real-time closed-loop track-following experiments. Combining these technologies, we achieved a position-error signal (PES) with a standard deviation of 10.3 nm. This magnitude of PES in combination with a 90-nm-wide reader allows the writing and reading of 177-nm-wide tracks at 600 kb/in, for an equivalent areal density of 85.9 Gb/in $^{2}$ . This paper clearly demonstrates the continued scaling potential of tape technologies based on low-cost particulate media.