The data recovered from compact discs are contaminated with errors that exhibit a bursty behavior. A channel model is developed to characterize the error bursts and good-data gaps that occur in actual data recovered from compact discs. The probability of having m erroneous symbols in a data block of length n symbols is calculated using the channel model. This probability can be used to evaluate the performance of the error-correction code (ECC) used in the compact disc system.

The authors analyze how shift errors propagate in a particular run-length limited (RLL) modulation code that is widely used in modern high-density data storage machines. More specifically, the probability that either a one or two byte burst error in the user data will result from an arbitrary channel data shift error is calculated. The authors consider the case in which the spatial recording density, is near the intrinsic resolution of the head/medium interface; here shift errors occur with high probability only for certain worst-case patterns of channel data, i.e., when the channel 'one' under consideration represents a recorded write signal transition that suffers intersymbol interference (ISI). The authors treat the case in which the recorded indicia on the medium are well resolved on playback; here shift errors are equally probable at all channel 'one' locations.>