Estimation of recovered data reliability for two compact disc recording formats

Abstract

The error-handling capability of the Compact Disc Error Correction Code (ECC) is influenced by the statistical distribution of the errors that contaminate the recorded data. Error measurement hardware and software are developed to examine the recorded data on Compact Discs and report the locations of the erroneous data with single-byte resolution. A sample population of 8 read-only and 8 write-once Compact Discs are subjected to error measurement and the recovered error statistics are compared for the two types of media. A novel Markov state machine is developed to quantitatively characterize the measured errors and produce block-error probability rates at the input of the ECC decoder. These probability rates are used to obtain reliability estimates for the recovered data bytes at the output of the ECC decoder. The capability of the Compact Disc's ECC decoder to detect and subsequently correct the erroneous data bytes is greatly influenced by the particular decoding strategy used by the ECC decoder. The performance of seven different ECC decoding strategies that are applied to the recovered data from read-only and write-once Compact Discs are evaluated. In addition, the ECC decoder performance of a newly proposed Compact Disc recording format known as the Compact Disc-Direct Access Storage Disc (CD-DASD) is investigated. Reliability estimates for the data occurring at the output of the CD-DASD ECC decoder is compared to that of conventional CD-ROM's Cross-Interleaved Reed-Solomon Code decoder.