Barcode operations
Barcode reading is mainly a function of the robot hardware instead of media and device management. When a robot has a barcode reader, it scans any barcode that is on a tape and stores the code in its internal memory. This associates the slot number and the barcode of the tape in that slot. NetBackup determines that association for its own use by interrogating the robot.
If a robot supports barcodes, NetBackup automatically compares a tape's barcode to what is in the EMM database as an extra measure of verification before you mount the tape. A request for the media that is in a robot that can read barcodes begins in the same manner as other requests.
The ltid command includes the media ID and location information in a mount request to the robotic daemon for the robot that has the media ID. This request causes the robotic daemon to query the robotic-control daemon or the robot for the barcode of the tape in the designated slot. (This is a preliminary check to see if the correct media is in the slot.) The robot returns the barcode value it has in memory.
The robotic daemon compares this barcode with the value it received from ltid and takes one of the following actions:
If the barcodes don't match, and the mount request is not for a NetBackup backup job, the robotic daemon informs ltid and a pending action request (Misplaced Tape) appears in the Device Monitor. An operator must then insert the correct tape in the slot.
If the barcodes don't match and the mount request is for a NetBackup backup job, the robotic daemon informs ltid and the mount request is canceled. NetBackup (bptm) then requests a new volume from nbjm and from EMM.
If the barcodes match, the robotic daemon requests the robot to move the tape to a drive. The robot then mounts the tape. At the start of the operation, the application (for example, NetBackup) checks the media ID and if it also matches what should be in this slot, the operation proceeds. For NetBackup, a wrong media ID results in a "media manager found wrong tape in drive" error (NetBackup status code 93).
