Tapes released to scratch without HSM

Cause

This happens occasionally and it is not very easy to determine how it happened.

First, it is important to know what type of tape management system the customer is using. When HSM is done with a tape, it returns the tape to the tape management system through an exit.  If RMM is being used, the tape is returned via the EDGTVEXT exit.  For all other OEM  tape management systems, a tape is returned via the ARCTVEXT.  RMM supplies the EDGTVEXT exit.  the ARCTVEXT is "user written", and it is typically supplied by the OEM vendor that owns the tape management system.

The only way HSM can return a tape back to the tape management system is through the tape exit (EDGTVEXT or ARCTVEXT).  For a BACKUP, ML2, or DUMP tape, the exit is called only after the tape successfully goes through DELVOL processing.  During DELVOL processing, the volume record is deleted (MCV for ML2 tape, MCT for BACKUP tape, and DVL for DUMP tape), and the TTOC record is deleted for ML2 and BACKUP tapes.  

So if a tape is in scratch status in the tape management system, but HSM still has a volume record and (for ML2 and BACKUP tapes) a TTOC record, then the tape did not go through DELVOL processing and was not returned via the HSM tape exit.  This process is single threaded.  If anything fails during DELVOL processing, the tape exit is not called and the tape is retained by HSM.

ML2 tapes:   FIXCDS V volser
                         LIST TTOC(volser)

B/U tapes:   FIXCDS X volser
                        LIST TTOC(volser)

Dump tape: FIXCDS Y volser

If any of the volume records above are still in HSM, then HSM didn't DELVOL the tape, and HSM didn't return it to scratch via the exit.

Tapes issued to HSM from the tape management system should be marked "EDM" and have a 'never expire' expiration date.  Thus, the tape is completely under HSM control until it is returned to the TMS via ARCTVEXT or EDGTVEXT.

For the customer to have a tape that TMS says is scratch, but HSM has records of it, means the tape was returned to the TMS outside of HSM control.  This could have been done manually.  But something outside of HSM returned the tape to the TMS.  

The customer should engage the OEM vendor of the tape management system that is being used to get help to determine when the tape was returned.  Unfortunately, the tape may have been issued out more than once, so the last time it was returned may not be the time that it was returned to scratch from underneath HSM control.  

If the customer is using RMM, one common way tapes get returned to scratch without HSM's knowledge is because of a lack of an ABEND VRS that is needed to protect HSM tapes.  When a problem occurs during tape access, RMM will set the expiration date for the tape to 2 days.  An ABEND VRS that covers HSM tapes prevents this action.   RMM also has "Facility Classes" that can be set up to prevent a user from outside of HSM from returning an HSM tape to scratch.  I'm unaware of OEM tape management systems having this capability.