Option to turn off checkpointing for GSAM files

Currently, IMS sets the DS1CPOIT flag in the Format-1 DSCB for all GSAM files used by an IMS program, such as a BMP. This flag is left on regardless of whether the program terminates normally or not, leading to many thousands of checkpoint files left in the system, even though in the vast majority of cases these files have no checkpoint value since the program can't be restarted anyway.
In order to avoid DASD management issues, DFSMShsm and DFSMSdss have included options to ignore the checkpoint flag (DS1CPOIT) while doing housekeeping such as space management or similar. This has led to an absurd situation where IMS indicates datasets are checkpointed, and DASD management outright ignores the indicator. Now, this would not be a problem if it weren't for the (theoretical) case where a program ends abnormally (thus leaving a pending restart situation), and HSM needs to migrate the dataset before a restart happens. This would mean that the checkpointed dataset is no longer valid, and a potential data corruption might ensue.

We suggest that IMS introduce an option to not leave the DS1CPOIT flag if the program terminates normally. (We leave it up to IMS development to define what constitutes 'normally', though we feel it should be along the same lines as DBRC or similar use to define a run as not-restartable.) This would give us the option to instruct HSM/DSS to not ignore the bit, and we would thus ensure data integrity.
The option could be 3-tiered:
- An IMS system option defining a default behaviour,
- An option on the PSB to override system default, and/or,
- An invocation option on DFSRRC00 to override the option for a specific run only.
We would prefer it if we could get the option in all 3 places, if possible.