This part of IEC 62702 specifies a method of data-quality assurance for writable DVD disks (hereinafter disks) which are specified for long-term data storage, and a data migration method which can sustain the recorded data on disks for long-term audio data preservation. The writable disks include recordable disks such as DVD-R, and +R format, and rewritable disks such as DVD-RW, +RW format and DVD-RAM.