The close routine is entered when the processing program issues a CLOSE macro. If the processing program terminates without closing the data set, the operating system calls the close routine, which restores the fields of the DCB to the conditions that existed before the data set was opened. It also logically disconnects the data set from the processing program, and creates output trailer labels, and provides for tape disposition. If DFSMSrmm is in use, statistics about processing are recorded in the DFSMSrmm control data set.