Ignoring obsolete messages (DISCARD_MSG)

If the message queue contains obsolete messages, then you can delete them with the ROBAR-SV statement DISCARD_MSG, see section "DISCARD_MSG Discard obsolete messages from the message queue" in chapter "File message_resp". For this, messages contained in the message queue (.../cmx/robar.mess) are compared with the parameters of the DISCARD_MSG statement. The entries that refer to the same device or cartridge and that have not yet been processed are marked as invalid.
Note that only the messages present in the file at the time the command is issued are deleted, not the messages that are added after the command was issued.

If an error occurs (e.g. LDCK- Load Check) while a cartridge is being mounted in a device, the following events ensue:

• NDM issues message NKVT013 and instructs ROBAR to mount the cartridge in a device.

• The robot inserts the cartridge in a device. This causes an LDCK error.

• The device error recovery issues message EXC0858. Via inserts, this message informs you of the error that occurred and of the affected device.

• The TM (tape monitor) task deletes the current NKVT013 message and NDM issues a new NKVT013 message with the same information for the archive number and the mnemonic device name.

• The new NKVT013 message is added to the ROBAR-SV message queue.

ROBAR’s reaction depends on the value set for action key MRV21 (see the ROBAR rule file message_resp on "File message_resp"):

• delete current job option
  If ROBAR receives message EXC0858 for an archive number, the relevant current job is deleted using the /CHANGE-TAPE-MOUNT ACTION=CANCEL,UNIT=mn command, as a result of which the MOUNT process for the cartridge has no basis. The commands UNLOAD-TAPE to the BS2000 system and KEEP to the archive system cause the defective cartridge to be removed from the device. The new message NKVT013 for the archive number and for the device is removed from the message queue. This stops ROBAR from causing the cartridge to be mounted again as this would have undesired side effects (LDCK would occur again, the wrong cartridge would be mounted, etc.).

• retry on another device option
  ROBAR issues the /CHANGE-TAPE-MOUNT ACTION=MOVE,UNIT=mn command in order to have the cartridge mounted in another device. This allows ROBAR to find out whether the error was caused by the cartridge or by the device. In this case, too, it is not necessary for the MOUNT to be completed on the first device. However, before the cartridge can be mounted on another device, it has to be removed from the device (by issuing the UNLOAD-TAPE command to the BS2000 system and KEEP to the archive system). The new message NKVT013 for the archive number and for the first device is removed from the message queue.