Abstract: This disclosure describes an item drop location for placing items that have been picked from an inventory location within a material handling facility but have not yet been transitioned from the materials handling facility and a return location for returning items that have been transitioned from the materials handling facility. Likewise, described is a system and method for identifying an item placed at a drop location or an item placed at a return location, processing the placed item and providing confirmation to a user that placed the item and facilitating a return of the item or a removal of the item from an item identifier list associated with the user.

Abstract: This disclosure describes a system for determining an estimated user departure time from a materials handling facility. For example, a user may enter a materials handling facility to pick one or more items from the materials handling facility. Those items may be provided to an agent for processing, such as packing, while the user picks other items within the materials handling facility. To ensure that the items are processed in a timely manner and made available to the user when the user is ready to depart from the materials handling facility, the implementations discussed determine an anticipated user departure time and compare that time with an estimated processing time needed to process the items.

Abstract: This disclosure describes an item drop location for placing items that have been picked from an inventory location within a material handling facility but have not yet been transitioned from the materials handling facility and a return location for returning items that have been transitioned from the materials handling facility. Likewise, described is a system and method for identifying an item placed at a drop location or an item placed at a return location, processing the placed item and providing confirmation to a user that placed the item and facilitating a return of the item or a removal of the item from an item identifier list associated with the user.

Abstract: The application describes a system and process for anticipating when a user will leave a selection area within a materials handling facility and determining if a notification requesting that the user provide a tote of picked items to a drop off location should be presented to the user. For example, a user may be asked to provide items picked from a selection area for processing, such as packing, while the user is picking items from other selection areas of a materials handling facility.

Abstract: This disclosure describes an item drop location for placing items that have been picked from an inventory location within a material handling facility but have not yet been transitioned from the materials handling facility and a return location for returning items that have been transitioned from the materials handling facility. Likewise, described is a system and method for identifying an item placed at a drop location or an item placed at a return location, processing the placed item and providing confirmation to a user that placed the item and facilitating a return of the item or a removal of the item from an item identifier list associated with the user.

Abstract: Methods and apparatus for distributed locking interfaces are disclosed. A state manager implements programmatic interfaces for distributed locking operations. In response to a queue-for-lock request for a registry element received via an interface, the state manager provides to the requester, a reference to a first asynchronous computation. The first asynchronous computation comprises an insertion of a lock request into a queue of waiters for a lock on the element. In response to a blocking request for a result of the computation, the state manager transmits, after the lock request has been inserted into the queue of waiters, a notification of the insertion of the request. The notification in turn includes a reference to a second asynchronous computation. The second asynchronous computation comprises a grant of the lock on the particular element to the requester.

Abstract: Methods and apparatus for distributed locking interfaces are disclosed. A state manager implements programmatic interfaces for distributed locking operations. In response to a queue-for-lock request for a registry element received via an interface, the state manager provides to the requester, a reference to a first asynchronous computation. The first asynchronous computation comprises an insertion of a lock request into a queue of waiters for a lock on the element. In response to a blocking request for a result of the computation, the state manager transmits, after the lock request has been inserted into the queue of waiters, a notification of the insertion of the request. The notification in turn includes a reference to a second asynchronous computation. The second asynchronous computation comprises a grant of the lock on the particular element to the requester.

Abstract: Methods and apparatus for a semaphore mechanism in a distributed computing environment are disclosed. A state manager coordinating accesses to objects from distributed clients implements programmatic interfaces for semaphore operations. A client process submits a permit record directed to a semaphore instance protecting a shared resource. The client process receives a representation of permit records associated with the resource. The permit records provide an indication of an order in which permit requests for the resource were processed. The client process uses the permit records to determine whether it has been granted a permit, and if it determines that the permit has been granted, performs operations on the resource.