In IMS, only the following subfunctions are supported: NULL, "FINDbbbb", "PROGRAMb", "DBQUERYb".

For NULL subfunction, ART/IMS can only return the PCB related information that ART/IMS can support into the I/O area. "Terminal Location" and "Transaction Location" are only supported using "LOCAL".

For "FINDbbbb", the PCB address is returned in the AIBRSA1 field.

On 64-bit platform, the first 4 bytes of AIBRES3 is also used because the address length is 8 bytes.

Subfunction "PROGRAMb" returns the program name in the first 8 bytes of the I/O area.

For "DBQUERYb" subfunction, if there is no DBPCB in defined in PSB, "BJ" is returned in the IO PCB status. Otherwise, the IO PCB status is returned according to database availability.