The z/OS® DFSMS Open/Close/End-of-Volume (OCE) component is a set of system routines that builds the control block structure that connects the application, access method, and the operating system. OCE modifications include passing the media type and recording technology to DFSMS, DFSMSrmm, OAM/Library Automation Communication Services, and to the tape installation exits. OCE also supports performance scaling and performance segmentation with MEDIA5 and MEDIA9 cartridges and also ensures that performance scaling or performance segmentation persists across all volumes of a multivolume data set. During CLOSE of file sequence 1 on a performance scaled or performance segmented cartridge, performance scaling or performance segmentation is externalized in message IEC205I.

The OCE routines also include the IFGTEP macro with several fields for mapping installation exit parameter lists. Values that can be returned are: EFMT1 and EFMT2 in TEPMRECTK recording technology, MEDIA5, MEDIA6, MEDIA7, MEDIA8, MEDIA9 and MEDIA10 in TEPMMEDT media type.

Related reading:

• See z/OS DFSMS Using Data Sets and z/OS DFSMS Using Magnetic Tapes for additional information about the OCE routines.
• See z/OS DFSMS Installation Exits for more information on OCE installation exit parameter lists.
• See z/OS DFSMS OAM Planning, Installation, and Storage Administration Guide for Tape Libraries for more information on tape volume records.
• See OCE modifications for 3592 Model J for more information on the existing WORM tape support.