The MOUNT command is the only type of library request that can be used to request a specific system-managed tape library device. (Requesting a specific device is also called demand allocation.) The request must specify a system- managed tape library volume.
Table 1 shows the possible volume and device combinations you can specify on the MOUNT command, and how the system will handle those inputs.
| Volume location: | Device location: | System action: |
|---|---|---|
| Non-library | Non-library | Processing continues |
| Non-library | Library | Issues error message IEF120I |
| Library | Non-library | Issues error message IEF113I |
| Library A | Library B | If volume and device are in different libraries — issues error message IEF111I |
| Library A | Library A | If volume and device are in the same library but the volume record for the device could not be obtained from the tape configuration data base — issue error message IEF150I. |
| Library A | Library A | If the requested device is not found in the device pools returned by the system – issue error message IEFA106I. |