Tape applications should release MTC devices after they have been completed to prevent operation of the archive system from being impaired.
The following command helps the operator to ensure smooth operation of the archive system (see also “Commands” [3]):
/MODIFY-MOUNT-PARAMETER UNLOAD-RELEASED-TAPE=*REGARDLESS-OF-USER-REQUEST(TAPE-FAMILY=*MBK), NEXT-TAPE-MOUNT=*LEAST-RECENTLY-USED-DEVICE, PREMOUNT-MSG=*IGNORE-USER-REQUEST
These settings cause cartridges to be unloaded immediately after they have been used, the devices to be reserved one after the other, and the display of the PREMOUNT message to be suppressed.
An unload operation is performed as follows:
By a console message (NKVT097 or NKVT011, if applicable) it is indicated that the BS2000 system initiated an unload request. In response, ROBAR sends a KEEP statement to the archive system, causing the robot to remove the cartridge from the specified device and place it to its original storing position.
In the default configuration of the ROBAR rule files, ROBAR initiates unloading of the cartridge only in exceptional cases (e.g. during a mount job on a device which is still loaded or after a serious device error). Since in ROBAR operation unloading is only possible via the BS2000 system, ROBAR-SV enters the /UNLOAD-TAPE command in the BS2000 system for this purpose. The KEEP statement which ROBAR-SV sends to the archive system only causes the cartridge which has just been unloaded to be returned to its storage location.