Direct Access Compact Disc vs. CD-ROM Reliability Estimates

Abstract

The Cross Interleaved Reed-Solomon Code (CIRC) used in CD-ROM for basic error correction/detection consists of two catenated, distance 5 Reed-Solomon codes. These two subcodes, which are called the C1 and C2 codes, have length 32 bytes and 28 bytes respectively. C1 and C2 can each correct any combination of t errors and e erasures in a given codeword, where t and e are jointly constrained by the inequality Specific values of t and e may be selected by a decoder when each C1 and C2 codeword is processed. The algorithm used to adaptively select the t and e values that apply when the C1 and C2 codes are jointly decoded is called the CIRC decoding strategy.