In IMSDB- PCB has a key role. Because this acts as program’s interface to the database. I-O PCB is the first one we need to give in Entry statement of a program.
There are 4 PCBs available:
- I-O- PCB : It will do DBCTL requests. If the program not using the IO PCB, so, no need to be defined in PSB generation. If the program is using IMSDC, so we need to define IO PCB in PSB generation.
- GSAM PCB: A PCB defines for GSAM applications. It is called GSAM PCB.
- Alternate PCB: If we want to divert the program flow to the other terminal, we use alternate PCB instead of I-O PCB.