ACB is a consolidation of PSB and DBD information.

► For online programs

ACBs must be prebuilt using the ACBGEN utility i.e., ACBGEN must be run which will merge DBD and PSB and generate ACB.

► For batch programs

ACBs can be generated either at execution time (dynamically using IMS.DBDLIB and IMS.PSBLIB as input (PARM=DL/I)) or ahead of time (prebuilt ACB from IMS.ACBLIB can be used (PARM=DBB)).