Abstract: A lightweight carousel is disclosed for use in an automatic cartridge library system, featuring a system of guide blocks and springs to hold tape cartridges securely but permit their removal and replacement by bidirectional manipulators. The manipulators carry hinged hooks that can be used to push cartridges radially outward, or upon flexing of the hinges, expand to grip the cartridge for pulling radially inward. A reflective optical sensor is used to confirm that each cartridge in the carousel is properly placed. Optical sensors also verify proper rotation of the carousel, index the carousel, and detect the presence of cartridges in the tape drives. The carousel carries drive pins which seat in tapered holes in an index plate, and is driven by a zero-backlash belt.