CICS Realtime (Scenario based) Interview Questions (11 - 20)

11. What is a two Phase commit in CICS?

A two-phase commit in CICS ensures atomicity across multiple resources (like VSAM, DB2, MQ) by coordinating updates in two phases:

  • Prepare Phase – CICS asks all participating systems if they're ready to commit. Each system votes "YES" (can commit) or "NO" (must abort)
  • Commit/Abort Phase – If all vote "YES": CICS tells all systems to permanently commit changes. If any vote "NO": CICS forces all systems to rollback changes

12. What is the purpose of the Program List Table?

The Program List Table (PLT) in CICS defines initialization programs that run when:

  • CICS starts up
  • A CICS region shuts down
  • A transaction is initiated for the first time

13. Which CICS system program is responsible for handling automatic task initialization?

The CICS system program (DFHSIP) responsible for automatic task initiation during system startup or when certain events (like file triggers) occur. It manages initial task scheduling and region control.

14. I have written a CICS program. What tables should I setup to run this program?

To run a CICS program, you need to define entries in the following control tables:

  • PPT (Program Processing Table) – Defines the program name and its attributes.
  • PCT (Program Control Table) – Maps the transaction ID (TransID) to your program.
  • FCT (File Control Table) (if files are used) – Defines the files your program will access.
  • RCT (Resource Control Table) (if DB2 tables are used) – Defines the plan your program will access.
  • DCT (Destination Control Table) (if TDQs are used) – Defines any Transient Data Queues used.

15. In which table would you make an entry for a BMS map?

A BMS map is defined in the PPT, just like application programs, to make it available for execution in CICS.

16. What is the option of the DFHDCT macro which makes it possible to recover logically deleted records from an Intrapartition TDQ?

Use REUSE=YES in the DFHDCT macro to enable recovery of logically deleted records in an Intrapartition TDQ.

17. What is the primary function of the Sign-on Table?

The Sign-on Table (SNT) in CICS is a security control table that:

  • Validates user IDs and passwords during login.
  • Associates users with security profiles or permissions.
  • Supports resource-level security using RACF or external security managers.

18. Which is the program which determines whether a transaction should be restarted?

The Restart Manager (DFHREST) is the CICS system program that determines whether a transaction should be automatically restarted after a failure.

19. Mention the 5 fields available in the symbolic map for every 'NAMED' field in the DFHMDI macro?

For every NAMED field defined in a DFHMDI BMS macro, the symbolic map automatically generates these 5 standard fields:

  • fieldnameO – Output field (data to be displayed)
  • fieldnameI – Input field (data entered by the user)
  • fieldnameA – Attribute byte (display/input characteristics)
  • fieldnameL – Length of data entered
  • fieldnameF – Modified Data Tag (MDT) flag

20. Name three ways the Modified Data Tag can be set on?

The Modified Data Tag (MDT) in CICS BMS maps can be set ON in three primary ways:

  • User Input: - Automatically set when the user types into an unprotected field.
  • FSET Attribute: - Use the FSET option in the map field to force MDT ON, even if the user doesn't type.
  • IC Attribute with Cursor: - When the cursor is placed in a field using the IC attribute, and the user presses Enter, MDT is set ON.