Abstract: Techniques for controlling mobile drive units (e.g., robots) in proximity to humans in a physical area are described. A management device may send an activity message to the mobile drive units instructing the mobile drive units to perform a set of activities. If a human is detected in the physical area, the management device or another mobile drive unit may send an activity command instructing a mobile drive unit to stop, reduce the speed at which it is traveling, to change its path of travel, or to continue performing its set of activities. If the mobile drive units do not receive the activity command, the mobile drive units may stop performing the set of activities. After the management device determines that the human has left the physical area, the management device may resume sending the activity message.

Abstract: Techniques and systems for storing and retrieving data storage devices of a data storage system are disclosed. In some embodiments, inventory holders are used to store data storage devices used by a data storage system. When data is to be transacted with the data storage devices, mobile drive units locate appropriate inventory holders and transport them to a device reading station, where an appropriate device retrieval unit transacts the data. After the data has been transacted, the data storage devices are returned to the appropriate inventory holders, and the inventory holders are placed by the mobile drive units in locations where they may be accessed in response to further data transactions.

Abstract: Techniques for controlling mobile drive units (e.g., robots) in proximity to humans in a physical area are described. A management device may send an activity message to the mobile drive units instructing the mobile drive units to perform a set of activities. If a human is detected in the physical area, the management device or another mobile drive unit may send an activity command instructing a mobile drive unit to stop, reduce the speed at which it is traveling, to change its path of travel, or to continue performing its set of activities. If the mobile drive units do not receive the activity command, the mobile drive units may stop performing the set of activities. After the management device determines that the human has left the physical area, the management device may resume sending the activity message.

Abstract: Techniques and systems for storing and retrieving data storage devices of a data storage system are disclosed. In some embodiments, inventory holders are used to store data storage devices used by a data storage system. When data is to be transacted with the data storage devices, mobile drive units locate appropriate inventory holders and transport them to a device reading station, where an appropriate device retrieval unit transacts the data. In some embodiments, each inventory holder includes a plurality of trays that are independently accessible to the device retrieval unit. After the data has been transacted, the data storage devices are returned to the appropriate inventory holders, and the inventory holders are placed by the mobile drive units in locations where they may be accessed in response to further data transactions.

Abstract: Techniques for making a physical area safe for a human to enter when mobile drive units (e.g., robots) are operating in the physical area are described. A management device may send an activity message to the mobile drive units instructing the mobile drive units to perform a set of activities. If a human is detected in the physical area, the management device may stop sending the activity command. If the mobile drive units do not receive the activity command, the mobile drive units may stop performing the set of activities. After the management device determines that the human has left the physical area, the management device may resume sending the activity message.

Abstract: Techniques and systems for storing and retrieving data storage devices of a data storage system are disclosed. In some embodiments, inventory holders are used to store data storage devices used by a data storage system. When data is to be transacted with the data storage devices, mobile drive units locate appropriate inventory holders and transport them to a device reading station, where an appropriate device retrieval unit transacts the data. The inventory holders are configured such that any of the mobile drive units may interchangeably interact with any of the inventory holders and/or the data device reading stations. After the data has been transacted, the data storage devices are returned to the appropriate inventory holders, and the inventory holders are placed by the mobile drive units in locations where they may be accessed in response to further data transactions.

Abstract: Techniques for making a physical area safe for a human to enter when mobile drive units (e.g., robots) are operating in the physical area are described. A management device may send an activity message to the mobile drive units instructing the mobile drive units to perform a set of activities. If a human is detected in the physical area, the management device may stop sending the activity command. If the mobile drive units do not receive the activity command, the mobile drive units may stop performing the set of activities. After the management device determines that the human has left the physical area, the management device may resume sending the activity message.