The storage and retrieval system includes an enclosure housing multiple carousel assemblies mounted on the top of each other, a control system, a first set of drive mechanisms, a second set of drive mechanisms, and an authentication device. The control system receives input and user identification information from the user from the authentication device and stores it in a memory. During storage access, the control system identifies an available storage compartment that is nearest to the door of the enclosure and allocates it for the user. During retrieval access, the control system identifies the allocated compartment to the user. The control system then monitors the drive system to rotate the corresponding carousel assembly so that the allocated storage compartment is positioned in front of the door of the enclosure. The control system then unlocks the door and the user can access the storage compartment.