The primitive operation Release is an operation in the reference layer. It notifies the end of manipulation of the grabbed object to the persistent storage. After the operation, the reference pointer which has been obtained by the grabbing operation of the object is no longer valid. For reduction of the usage of the main memory, the grabbed objects must be released as soon as their manipulations finish. The operations return True if successful.
There must be two types of releasing operations for the normal grabbing and the read-only grabbing.