When a volume is entered into an IBM automated or manual tape library, the cartridge entry installation exit (CBRUXENT) is invoked to approve or deny an enter request, and to set or verify the recording technology to be associated with a volume.

If a volume TCDB record does not exist for the entry of a private MEDIA9 or MEDIA10 volume, and there is no applicable recording technology being provided by the library's entry default data class, EFMT2 is passed to the exit. If the exit returns with a recording technology for a MEDIA9 or MEDIA10 volume and it is not EFMT2, EEFMT2, EFMT3, EEFMT3, EFMT4, or EEFMT4, the specification is considered invalid and the exit is disabled.

If a volume TCDB record does not exist for the entry of a private MEDIA11, MEDIA12, or MEDIA13 volume, and there is no applicable recording technology being provided by the library's entry default data class, EFMT4 is passed to the exit. If the exit returns with a recording technology for a MEDIA11, MEDIA12, or MEDIA13 volume and it is not not EFMT4 or EEFMT4, the specification is considered invalid and the exit is disabled.

If a volume TCDB record does not exist for the entry of a volume and the volume is being entered as a scratch volume, UNKNOWN will be passed to the exit and will be assigned when the volume is used during job processing.

If a TCDB volume record exists and the volume's recording technology or media type is not supported on the system processing the volume, in an ATLDS, the volume is left in the library manager insert category to be processed by a system with appropriate support.

The cartridge entry installation exit (CBRUXENT) is passed by register 1, the pointer to a parameter list mapped by CBRUXEPL.