https://www.ibm.com/docs/en/ims/15.1.0?topic=types-partitions-in-phdam-phidam-psindex-databases
IMS 15 - Database administration - Partitions in PHDAM, PHIDAM, and PSINDEX databases
You can view a HALDB database, whether it is a PHDAM, PHIDAM, or a PSINDEX database, as a single database whose records are divided into manageable sections...
database administrationimspartitions