An information storage medium comprising: an area for replacing data recorded on the medium by logical overwrite to update the data; an area for replacing defects occurring on the medium, wherein: a replacement block replacing the original block is recorded in the area for replacement by LOW, and comprises a data block corresponding to at least partial data of the original block which has been replaced by LOW using a read-modify-write process and in which a defect has been detected during the RMW process, and a defect list entry indicating a replacement state comprises location information of the original block and location information of the replacement block, and is recorded in the information storage medium; wherein the replacement block is a recording or reproducing unit block, which comprises a data portion containing user data and an additional information portion containing the location information of the original block; wherein the additional information portion is recorded with an error correction structure different from an error correction structure of the user data portion, and wherein the error correction structure of the additional information portion has a better error correction capability than the error correction structure of the user data portion. an area for replacing data recorded on the medium by logical overwrite to update the data; an area for replacing defects occurring on the medium, wherein: a replacement block replacing the original block is recorded in the area for replacement by LOW, and comprises a data block corresponding to at least partial data of the original block which has been replaced by LOW using a read-modify-write process and in which a defect has been detected during the RMW process, and a defect list entry indicating a replacement state comprises location information of the original block and location information of the replacement block, and is recorded in the information storage medium; wherein the replacement block is a recording or reproducing unit block, which comprises a data portion containing user data and an additional information portion containing the location information of the original block; wherein the additional information portion is recorded with an error correction structure different from an error correction structure of the user data portion, and wherein the error correction structure of the additional information portion has a better error correction capability than the error correction structure of the user data portion. a replacement block replacing the original block is recorded in the area for replacement by LOW, and comprises a data block corresponding to at least partial data of the original block which has been replaced by LOW using a read-modify-write process and in which a defect has been detected during the RMW process, and a defect list entry indicating a replacement state comprises location information of the original block and location information of the replacement block, and is recorded in the information storage medium; wherein the replacement block is a recording or reproducing unit block, which comprises a data portion containing user data and an additional information portion containing the location information of the original block; wherein the additional information portion is recorded with an error correction structure different from an error correction structure of the user data portion, and wherein the error correction structure of the additional information portion has a better error correction capability than the error correction structure of the user data portion.