We present-a low-complexity soft detection and soft decoding magnetic disk drive read channel with a modified soft-output signal space detector (S/sup 3/D) which uses 3D-110 equalization and an error/erasure decoding Reed Solomon (RS) code. The detector determines max-log reliability information for intersymbol interference (ISI) channels with stationary white and colored noise. It can be implemented with only little additional hardware compared to the ordinary signal space detector. The erasures of the RS code are determined by the soft information and by an additional inner error detecting code (EDC) which is matched to the error patterns of the S/sup 3/D. The proposed system permits an improvement of the decoding performance in practical hard disk applications.

The authors present a coding architecture suitable for magnetic storage systems. In data storage devices, several types of errors may occur. This includes random errors as well as burst errors of different lengths. A class of error control codes is presented, based on a multilevel coding architecture, that can correct several types of errors. The parameters of the multilevel codes can be adjusted to match the probability of each error type. The decoding algorithms of these codes allow for fast-error recovery since they are based on decoding algorithms for simple codes. A class of multilevel codes is constructed, based on Reed-Solomon codes, whose redundancy is minimal.>

Ideas which have origins in Shannon's work in information theory have arisen independently in a mathematical discipline called symbolic dynamics. These ideas have been refined and developed in recent years to a point where they yield general algorithms for constructing practical coding schemes with engineering applications. In this work we prove an extension of a coding theorem of Marcus and trace a line of mathematics from abstract topological dynamics to concrete logic network diagrams.