How To Find I-O PCB in IMS DB Program

A PSB must contain at least one PCB. If there is any system service calls or if there is any transaction management calls present in a program, then IO PCB must be defined in PSB.

The sequence of PCBs should be as below in a program:

Entry DLITCBL  Using   IO PCB

Alternate PCB

DB PCB

GSAM PCB

  • The definition of PCB is available in PSB.
  • If COMPAT=YES defined in a PSB of PSBGEN, means “IO PCB” is present in the program. Say, the program is IMSDC program.

PCB TYPE=TP   ==> IO PCB or Alternate PCB

PCB TYPE=DB   ==> DB PCB

PCB TYPE=GSAM   ==> GSAM PCB

  • Once, my friend has been asked a question in an interview- How could we say a program is involved IMSDC ?
  • The answer is, if “IO PCB” is present in the PCBs list, we can say that IMSDC is involved in that program.
  • COMPAT=NO, means, program should contain IOPCB that is for BMP programs
  • Alternate PCB ( TP PCB) also involved in BMP and MPP (IMSDC) programs.

Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.