Coding gain of Reed-Solomon codes on disk memories

The read channel of a typical Winchester disk is considered. The primary concern is with the performance of the decoder for the Reed-Solomon error-correcting code. Decreasing the signal-to-noise ratio of a disk increases its error rate. Use of an error-correcting code reduces this error rate. For a fixed error rate, then, the use of a particular error-correcting code can be balanced by a certain reduction in signal-to-noise ratio. This reduction is usually referred to as the coding gain of the code. The author calculates the coding gain of various Reed-Solomon error-correcting codes. The intent is to determine how low a signal-to-noise ratio can be supported by a particular error-correcting code. The results show that coding gains of 3-4 dB are achievable with codes of modest implementation cost