IntroductionHigh areal density recording requires advancement in both linear density and track density. In order to resolve the side-writing issue and the edge noise reading issue associated with high track density, discrete track recording (DTR) technology was proposed by some researchers recently [1], [2]. While the DTR technology offers many advantages, there are difficulties yet to be overcome. With the DTR media configuration proposed by Wachenschwanz, et al. [1], slider flyability becomes more challenging due to the land-groove structure. In addition, the discrete nature of the DTR makes the magnetic write width (MWW) narrower than its continuous counterpart (continuous track recording, CTR), resulting in lower signal amplitude. Therefore, it is the objective of this paper to evaluate the performance of DTR technology. Both tribological performance and electric performance were evaluated. Flyability and Tribology The DTR media were manufactured by an etching process at substrate level, and the magnetic layer was sputtered on the entire surface, including the lands and the grooves. Therefore, the groove needs to be deep enough to be effective (>20 nm). While the head/media clearance is measured from the slider body to the top surface of DTR media, the slider flying characteristics is a function of the distance from slider body to DTR disk's "mean plane". As a result, DTR sliders have softer air bearings, therefore, worse flying height tolerance and sensitivities to most parameters. In order to compensate for this shortcoming, implementation of dynamic fly height control (DFH) is necessary. In this project, air bearing was designed based on the mean plane flying height. The head/media clearance was verified by measuring the contact RPM at sea level, and the contact altitude at constant RPM. Magnetic Model and Parametric Test A custom-built recording system model was applied in this study. The model calculates the signal amplitude through the convolution of reader sensitivity and written track magnetization profiles. Magnetic and electronic noises were separately obtained by solving the well established analytical equations. When combined with the drive level track mis-registration (TMR) distribution, the model is capable to predict both on-track and off-track signal-to-noise ratio (SNR) and bit error rate (BER) performance. Furthermore, adjacent track squeeze (ATS) and write-unsafe (WUS) events can be simulated with the model. As expected, the on-track SNR and BER of DTR are generally worse than CTR, due to its narrower effective magnetic writer width (MWW) and not-enough gain from erase band noise reduction. The best scenario is DTR equivalent to CTR at the optimized land/groove ratio and reader width. In this model, adjacent track's side reading is assumed to be equally influential for both DTR and CTR, and its value is determined by reader skirt width. Although the on-track performance is not as promising, the model does show that DTR has advantage in off-track performance, such as ATS
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