research MEDIA_ID_BARCODE_CHARS
from page 400 of the media manager admin guide
MEDIA_ID_BARCODE_CHARS = robot_num barcode_length media_ID_rule
Note To use this entry, the robot must support barcodes and the robot type cannot be one of the API robots. If this entry is specified in vm.conf, it controls Media Manager media ID generation. This entry is read and interpreted on the host where vmcheckxxx and vmupdate are running as part of the robot inventory operation. You choose how media IDs are created by defining rules that specify which characters of a barcode on tape will be used. You also can specify alphanumeric characters to be inserted in the ID. Multiple media ID creation entries can be specified, allowing media ID generation to be specific for each robot; or for each barcode format having different numbers of characters in the barcode. This allows flexibility for multi-media. If MEDIA_ID_BARCODE_CHARS entries are not present in vm.conf or you enter an invalid entry, Media Manager uses the right-most (the last) six characters of the barcode to create its media ID as the default. robot_num is the robot number. barcode_length is the length of the barcode.
A media_ID_rule consists of a maximum of six fields delimited by colons. Numbers in the fields of the rule define the positions of the characters in the barcode that are to be extracted (numbering is from the left). For example, 2 in a field extracts the second character from the barcode. The numbers can be specified in any order. Characters prefixed by # in a field, result in that character being inserted in that position in the generated ID. Any alphanumeric characters that are specified must be valid for a media ID. You can use rules to create media IDs of many varied formats, but keep in mind that the difference in the label on the media and the generated media ID may make it difficult to manage your media. The following is an example rule and the resulting generated media ID: Barcode on the tape: 032945L1
Media ID rule: #N:2:3:4:5:6
Generated media ID: N32945Message was edited by:
Bob Stump