Data recording medium, data recording method, and data recording apparatus, including additional recording features

摘要

With data of four symbols (FIG. 11A), a parity of two symbols (FIG. 11B) is created. These six symbols are EFM-modulated. Each symbol of eight bits is converted into a pattern of 14 bits (FIG. 11C). In a pit/land sequence formed on a disc (FIG. 11D), two symbols are rewritten. One symbol is (0×40). When an additional recording process is performed for the bit/land sequence, the pit length becomes long (FIG. 11E). The reproduced 14-bit data is converted into eight bits on the reproducing side. Thus, the original data (0×40) is rewritten to (0×22). A parity is also changed so that the additionally recorded data symbol (0×22) is not detected as an error.