DSNPDSM
DSNPDSM controls Data Services Manager (DSM) access for physical data set access.
The Data Manager Address Space controls all physical allocation and actual I/O. If DSNPDSM was called, physical I/O was required and that action had to be taken to obtain access to the physical data set.
Reference Sources
IBM Db2 for OS/390, Installation Guide, GC26-8970
IBM Db2 for OS/390, Messages and Codes, GC26-8979
IBM Db2 for OS/390, Application Programming and SQL Guide, SC26-8958
IBM Db2 for OS/390, Administration Guide, SC26-8957