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 MEDIA5, MEDIA6, MEDIA7, or MEDIA8 volume and there is no applicable recording technology being provided by the library's entry default data class, EFMT1 is passed to the exit; UNKNOWN might be passed for a scratch volume. If the exit returns with a recording technology for a MEDIA5, MEDIA6, MEDIA7, or MEDIA8 volume, and it is not EFMT1, EFMT2, or EEFMT2 (UNKNOWN is also allowed for a scratch volume), the specification is considered invalid, and the exit is disabled.

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; UNKNOWN might be passed for a scratch volume. If the exit returns with a recording technology for a MEDIA9 or MEDIA10 volume and it is not EFMT2 or EEFMT2 (UNKNOWN is also allowed for a scratch volume), the specification is considered invalid and the exit is disabled.

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 via register 1, the pointer to a parameter list mapped by CBRUXEPL.

If CBRXLCS FUNC=MCE is used to enter a volume into an MTL and its existing TCDB record has EEFMT2 recording technology or an unsupported media type (MEDIA9/MEDIA10, V1R4 system) and the software does not support the recording technology or the media type, the request fails with existing return code LCSFAIL (12) and existing reason code LCSFNSUP (310). If the CBRUXENT exit returns a unsupported recording technology or media type, the entry of the volume also fails.