Abstract: An improved carousel apparatus for use in carousel-type magnetic tape library systems and the like, including a cylindrical magazine carried by a rotatable turntable. The turntable includes a sprocket wheel that is engaged by a drive belt or chain connected to a stepper motor affixed to a rotatable base plate. Affixed to the sprocket is a shutter plate having a plurality of notches in its perimeter for detection by an optical-indexing sensor. The apparatus also includes a carousel-indexing sensor and a cartridge-in-carousel and cartridge-orientation sensor. Disposed within the central cavity of the carousel magazine unoccupied by cartridges is a cartridge-onloading/offloading mechanism which is rotatably mounted concentric with the carousel turntable.