Persistent object state refers to information about an object that must be preserved beyond the object's lifetime. Persistent states are typically stored in nonvolatile memory, such as hard disks or battery-backed RAM. To make a persistent object in COM, the object must support a persistent object interface. COM uses the persistent object interface to coordinate operations for initializing, loading, and saving persistent objects. To conform to the COM persistent object protocol, client applications determine when and where an object should store its state and the object determines the format for data storage. A persistent object must also implement the IPersist interface because all persistent object interfaces inherit from it. In Windows CE, only structured storage can be made persistent.