Abstract: Apparatus and method for storing magnetic tape format data separately stores the tape data from the tape-related information, such as file markers and interblock gap signals. The data and data-related signals are stored in separate finite length buffer memories, which when filled to a predetermined capacity are transferred to a write-once read-many (WORM) optical disk, and stored in contiguous locations beginning at one end of the addressable space on the optical disk. A separately generated tape record map list, including the WORM optical disk address of the aforementioned tape data and tape-related signals is created and stored on the optical disk in sequentially contiguous locations corresponding to sequential tape reel numbers beginning at the opposite end of the addressable space on the optical disk. The data thus recorded on the WORM optical disk is recoverable in the original magnetic tape format by recomposing the data stored in the WORM optical disk in the original magnetic tape data format.