Abstract: A number of data storage cassettes are held in a removeable magazine that forms part of a tape drive by which the magnetic tapes are recorded or played. The magazine holds two parallel vertically-displaced decks of cassettes that are moved under positive driving force along a rectangular pathway formed by the two decks. From a pick-up position in the magazine, a cassette is automatically extracted by a robotic arm and placed in the tape platform for reading or writing by a conventional tape drive mechanism. When the use of the cassette is finished and it is ejected by the tape drive, a sensor activates the robotic arm to return the cassette to the pick-up position. Each deck has one unoccupied cassette space. If during the sequence of operations, the cassettes on the lower deck are moved by the width of one cassette in one direction, the cassettes on the upper deck are moved the same distance in the opposite direction.