Data recording medium, data recording method, and apparatus

摘要

Output data of a multiplexer 11 is EFM-modulated by an EFM modulator 12. In the EFM modulation, merging bits that satisfy run length limit conditions Tmin=3 and Tmax=11 are selected. Among them, merging bits that converge DSV are selected. A run length controlling portion 13 detects a particular data pattern that causes DSV to increase as large as a data read error takes place and controls the EFM modulator 12 so that the run length limit conditions of the EFM are loosened. As a result, an increase of DSV is suppressed. Data is reproduced from a data recording medium on which the data has been recorded in such a manner and the reproduced data is decoded. The decoded data is re-encoded so as to record it to another recoding medium. When the data pattern is re-encoded, DSV increases. As a result, data cannot be correctly reproduced from the other recording medium. Consequently, a copying operation can be prevented.