Consists of an integrated computer-controlled system that combines the storage medium, transport mechanism, and controls with various levels of automation for fast and accurate random storage of products and materials
Storage/retrieval (S/R) machine in an AS/RS operates in narrow aisle, serving rack slots on both sides of aisle; can travel in horizontal (along the aisle) and vertical (up and down a rack) directions at same time
Advantages: fewer material handlers, better material control (including security), and more efficient use of storage space
Disadvantages: high capital and maintenance costs, and difficult to modify