Provided is a storage mechanism that readably migrates a content of data from one recording medium to another over generations in a readable manner and provides the contents of the records from a current recording medium. A read/write controller comprises a mechanism for preparing an archive recording medium of a first generation having a plurality of records recorded therein and a mechanism for migrating the records from the recording medium of the first generation to a recording medium of the next generation (the third generation subsequent to the first generation) and further to recording media of following generations one by one. The migration mechanism generates migration information including a mapping table between record numbers of the first generation and a current generation and holds the migration information as data in the recording medium of the current generation.