Design of advanced digital magnetic recording systems

The development of advanced digital magnetic recording systems requires every significant system parameter to be optimally designed since the margins for reliable operation are shrinking very rapidly. The performance of these high density systems is primarily limited by the writing-demagnetization processes which are highly non-linear and interactive. Consequently, design by trial and error is unsatisfactory besides being very time consuming and expensive. Theoretical design and optimization can be fast and efficient, but requires a modeling technique which can accurately simulate the non-linear interactive processes, and incorporate all the frequency and wavelength-dependent effects in the transducer, the medium, and the circuits. The dynamic iterative model meets these criteria and is used in this paper to simulate the performance of advanced digital disk systems. The theoretical predictions are compared to experimental measurements from an IBM 3340 disk system, and the correlation is very good for both the spatial distribution (timing) and the absolute amplitude of the signal response.