Patent ID: 7522489

Claim:
An initialization method for initializing an information recording medium including a data zone, a replacement area, and a management information area storing management information of the data zone by recording dummy data by a block unit having a predetermined data size to a non-recorded area of the information recording medium, comprising the steps of: determining a block to record the dummy data by referring to identification information for identifying a block recording user data and a block in which the user data are not recorded, and information concerning a last address of a recorded area continued from a beginning of the data zone; and recording the dummy data to the block being determined in the step of determining a block to record the dummy data; checking for a defect in the data zone; and replacing a defective block where the defect is detected with a replacement block in the replacement area, referring to the identification information, and recording the dummy data to the replacement block when the defective block is not the block where the user data are recorded; wherein the management information includes a check information showing whether or not the identification information is valid; and the check information is set to show that the identification information is invalid, when a defect detection in the data zone is completed.