The most important thing to remember when setting up or changing the SCRPOOL ASSIGN file is that as soon as a record is found that matches the criteria specified on the MOUNT command, the volser is chosen from that pool when a specific pool is not included.
VM:Tape reads the records in the file one at a time starting from the top until one is found that matches the DataSetName (DSN) / User ID (JOB) on the MOUNT command. A record with no specific value will be chosen if found before a record that has a specific value.
MOUNT from USERID HIDRO DSN HIDRO.WEEKLY.OFFSITE
SCRPOOL ASSIGN records"
For VM:Tape to default and pick volsers from POOL=HIDRO for the above mount request, the first record needs to be moved below the current second record in the SCRPOOL ASSIGN file. If you need to leave the file as-is so that every mount request will default to picking volsers from POOL=SCRATCH, then any mount request needing a tape from a different pool will have to include the POOL option on the MOUNT command. In the above example, POOL HIDRO would have to be included on the MOUNT command. A corresponding record authorizing the DSN / User ID combination to use a pool must be coded somewhere in the SCRPOOL ASSIGN file, otherwise the mount request will be rejected.
MEDIA and DENSITY values do not influence the pool selection if they are included on the MOUNT command. After the pool has been selected, then VM:Tape confirms if tapes of the requested MEDIA and DENSITY are available in that pool. If none exist, an error message is issued indicating no tapes of the requested MEDIA/DENSITY exist in the selected pool and the mount request is cancelled.