Recording medium, apparatus and method for additional recording of information data recorded on a recording medium with an error correction code

Abstract From the Canadian patent

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 (0x40). 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 (0x40) is rewritten to (0x22). A parity is also changed so that the additionally recorded data symbol (0x22) is not detected as an error.