If existing subsystems are physically removed from a library, then perform the following steps to accurately reflect the new configuration:

1. Use HCD to delete all devices from the library.
2. Activate the IODF that has the devices from the library removed by activating from the ISPF HCD panels, or by entering the MVS ACTIVATE command on the z/OS console.
3. Use HCD to add all of the devices that are now in the library.
4. Activate the IODF that has all the devices defined by activating from the ISPF HCD panels, or by entering the MVS ACTIVATE command on the z/OS console.
5. Vary the devices online to MVS using the MVS VARY command.
6. Once again, activate the IODF containing all of the tape devices to complete the configuration activity by activating from the ISPF HCD panels, or by entering the MVS ACTIVATE command on the z/OS console.
   Note: Steps 1–6 can be replaced with a system IPL using an IODF that has the deleted devices removed.

   If the deleted subsystems are then added to another library, follow the steps documented in Adding subsystems to a library.

The sections above assume that as subsystems are added, moved, or deleted, previously existing subsystems may now be associated with different subsystem IDs. The sections above also document the steps necessary regardless of whether the subsystem IDs at the library manager have changed.

If the steps documented in the sections above are not followed, you may have the same device being configured in multiple device pools or the appearance of more drives then are actually in the library, or both, resulting in subsequent failures during library processing.