A System Level Study of Two-Dimensional Magnetic Recording (TDMR)

Two-dimensional magnetic recording (TDMR) is a recently proposed recording scheme aimed at extending the life of conventional granular magnetic recording (CGMR) without a significant modification to the writer, reader or medium. This is atypical, as these are the usual sources of areal density gain in the history of magnetic recording. TDMR is the readback counterpart of shingled magnetic recording (SMR) that is currently being implemented by the hard drive industry today. SMR/TDMR gains are in parallel with those from HAMR and BPMR and the total gains from TDMR + HAMR or TDMR + HAMR + BPMR can be accumulated. TDMR was originally proposed as a very high-density contender for conventional granular media, using coding and signal processing to try to make up the gaps. Initial expectations have yet to be realized as the simulations yielded high error rates when the density is in the regime approaching single grain per bit. Nonetheless, TDMR still has something to offer when used in a closer-to-conventional regime, of around 5-10 grains per bit. However, the system architecture for SMR and TDMR has not been well studied and the effects of the block sizes and various other system parameters is not well known in an SMR/TDMR system. In this work, we perform a study on TDMR/SMR at the system level using micromagnetic simulations and the grain-flipping probability (GFP) model to calculate the final system error rates. We study the effect of variable shingle-block dimensions, aspect ratios and reader-offsets. The experiments in this work, carried out via micromagnetic simulations and the GFP model, yield insights into the SMR/TDMR architectures, and predict estimated gains of TDMR + SMR over SMR alone.