MARC format is designed for bibliographic data communication. Among the MARC world, CMARC adopts UNIMARC approach rather than USMARC tradition. The fourth edition of CMARC was published in 1997. Based on several considerations, it not only abandons Linking Entry Block completely, but also skew to USMARC habits. CMARC lost its compatibility with UNIMARC which might cause chaos in the near future.