CICS Realtime (Scenario based) Interview Questions (21 - 30)
21. What is the difference between FSET and FRSET?
In CICS BMS, FSET and FRSET are attributes used to control field behavior in symbolic maps:
FSET (Force Set):
- Forces the Modified Data Tag (MDT) to be ON for a field, ensuring it is always transmitted to the program (even if unchanged).
- Set via ATTRB=FSET in the DFHMDF macro or programmatically by setting the attribute byte (fieldname+F) to X'01'.
- Guarantees the field is included in RECEIVE MAP.
FRSET (Field Reset):
- Forces the MDT to be OFF, meaning the field is not transmitted unless modified by the user.
- Set via ATTRB=FRSET in DFHMDF or by setting the attribute byte to X'00'.
- Excludes the field from RECEIVE MAP unless explicitly edited.
22. What is the difference between the enter key, the PF keys and the PA keys?
| Key Type | Purpose | CICS Handling |
|---|---|---|
| Enter | Submits the current screen data | Sets EIBAID=DFHENTER |
| PF Keys (PF1–PF24) | Triggers application-specific functions | Sets EIBAID=DFHPF1 to DFHPF24 |
| PA Keys (PA1–PA3) | Emergency/interrupt actions | Sets EIBAID=DFHPA1 to DFHPA3 |
23. What do the keywords MAPONLY and DATAONLY mean?
In CICS BMS, MAPONLY and DATAONLY are keywords used with the SEND MAP command to control screen output:
| Keyword | Purpose | Effect |
|---|---|---|
| MAPONLY | Sends only the map’s static fields (labels, fixed text) | Ignores variable data fields; redisplays the screen layout without updating dynamic content. |
| DATAONLY | Sends only variable data fields (user-input/output fields) | Skips static text; updates only modifiable fields (e.g., for partial screen refreshes). |
24. What are the two outputs created as a result of generation of a map?
When a BMS (Basic Mapping Support) map is generated, it produces two key outputs:
- Physical Map (Load Module) – Stored in the CICS load library, used by CICS to display the screen. Stored in a CICS load library (DFHRPL).
- Symbolic Map (Copybook) – Source code (e.g., COBOL/PL/I copybook) defining field names and attributes.
25. What is the use of DSECT parameter in BMS?
The DSECT parameter in BMS is used to generate the symbolic map only (copybook), without creating the load module. It is used when you only need the field definitions for program logic, not for actual screen display.
26. Can you use OCCURS in a BMS map?
Yes, you can use the OCCURS option within a BMS map definition to define repeated fields, essentially treating them as an array, but each element of the array is a single map field.
27. Can you define multiple maps in a BMS mapset?
Yes, you can define multiple maps (screens) in a single BMS mapset. Each map is defined with its own DFHMDI macro within the mapset's DFHMSD declaration.
28. What does the BUFFER option in RECEIVE mean?
The BUFFER option in the RECEIVE command tells CICS to place the entire inbound message into a specified storage area (buffer), without mapping it to a screen layout. Typically used in non-BMS applications or for raw data input.
29. What is the option that is used to erase all unprotected fields during a SEND MAP operation?
The ERASE option in the SEND MAP command is used to clear all unprotected fields on the screen before displaying the map.
30. What is DFHEIBLK?
DFHEIBLK (Execute Interface Block) is a CICS-provided control structure that supplies critical runtime information to a CICS program. It contains:
- Task/Transaction Data (e.g., transaction ID, terminal ID).
- Response Codes (e.g., EIBRESP, EIBRCODE for error handling).
- Command-Specific Details (e.g., length of data received).