Abstract: A method for storing inventory items in an inventory system includes receiving a replenish request identifying an inventory item to be stored in an inventory system and determining a classification of the inventory item to be stored. The method also includes selecting an inventory holder from a plurality of inventory holders based, at least in part, on the classification of the inventory item to be stored and a classification of one or more other inventory items currently stored in the selected inventory holder. Additionally, the method includes transmitting information identifying the selected inventory holder to a mobile drive unit.

Abstract: A method for retrieving inventory items within an inventory system includes receiving a retrieval request that identifies an inventory item and selecting, from a plurality of inventory stations, an inventory station to fulfill an order associated with the retrieval request. The method also includes selecting an inventory holder from a plurality of inventory holders that store the inventory item and selecting, from a plurality of mobile drive units, a mobile drive unit to move the selected inventory holder to the selected inventory station.

Abstract: A method for storing inventory items in an inventory system includes detecting that an inventory holder is available for storage and determining a classification of the inventory holder. The method also includes determining a classification of each of a plurality of storage locations and selecting a storage location for the inventory holder based, at least in part, on the classification of the inventory holder and the classification of the selected storage location. The method additionally includes transmitting information identifying the storage location to a mobile drive unit associated with the inventory holder.

Abstract: A system for transporting inventory includes an inventory holder and a mobile drive unit. The inventory holder includes a frame capable of storing inventory items and a docking plate capable of receiving a docking head from underneath. The mobile drive unit, includes a docking head capable of coupling to the docking plate and a drive module capable of propelling the mobile drive unit. The mobile drive unit is further capable to move the inventory holder when the docking head is coupled to the inventory holder.