CICS Interview Questions

Introduction

CICS is a database/database system that is utilized in online applications. CICS was created because batch operating systems can only run batch programs. Its programs can be written in COBOL(Common Business-Oriented Language), C, C++, Java, and other languages. Users nowadays expect information in seconds and in real time. 

We need a system that can process information online to deliver such speedy service. CICS enables users to interface with the back-end system to obtain the required information. Online programs include online banking, flight reservations, and so on.

Let's look into some interesting questions for the topic CICS Interview Questions.

CICS Interview Questions for Freshers

1. What is CICS, and what is its primary aspect?

Ans. CICS, which stands for Customer Information Control System, is IBM software that monitors telecommunications. Time-sharing and batch are IBM mainframe operating systems.

CICS is primarily concerned with the execution and development of online applications. It creates a communication channel through the terminal and allows for the receipt and sending of structured data. One of the essential components of CICS is the accessibility of databases and the files they contain.

2. What does the CICS translator do?

Ans. The CICS translator turns EXEC( executive) CICS commands into call statements for a particular programming language.

3. What is the type of ppt in CICS, and what are the uses of the ppt?

Ans. Processing Programming Table (PPT) in CICS, the PPT comprises information such as the name of a program, Mapset names, task use counter, language, size, the primary storage address, and so on.

The following are the most common use of PPT in CICS:

• All must be entered into CICS and programmed into the Processing Programming Table.
   
• A PCP, or Program Control Program, is a type of program that mainly pertains to the PPT.
   
• You must register for the program here. If it is not noted, the CICS will not recognize it.

4. What is the definition of COMMAREA?

Ans. COMMAREA is usually a communication area since it is a temporary storage place. It serves as a data transfer medium between many applications loaded by a group of transactions or a single transaction.

5. What is the difference between multitasking and multithreading?

Ans. The operating system supports multitasking, which allows you to run multiple tasks at the same time. Under the multitasking environment, multithreading is the system environment in which tasks share the same program load module. It is a subset of multitasking since it involves tasks that use the same program.

6. What’s the CICS command used to access the current date and time?

Ans. The ASKTIME command is used to obtain the current date and time.

7. What does the CICS translator do?

Ans. The CICS translator turns EXEC CICS commands into call statements for a particular programming language.

8. Distinguish between an EXEC CICS XCTL command and an EXEC CICS LINK command.

Ans. The EXEC CICS XCTL  command transfers control to an application program at the same logical level without expecting power back. Still, the EXEC CICS  LINK command gives authority to an application program at the next logical level with the expectation of receiving control back. 

9. What is the purpose of DCT?

Ans. DCTs are Destination Control Tables, which are visually used in CICS to specify TDQ(Transient Data Queue).

10. In CICS, how are ENQ and DEQ used?

Ans. ENQ(Enquiry) and DEQ are task control commands that make a resource serially recyclable.

11. How can you turn on the MDT option even if no data is entered?

Ans. In DFHMDF(Defined Field Hierarchy Map Definition Fields), mention the FSET(Fieldset) option, or set it dynamically in the application using the FIELD+A attribute field.

12. What happens when the NOHANDLE option is used in a CICS command?

Ans. No action will be taken if an extraordinary condition occurs while this command is being executed. Even if an EXEC CICS HANDLE condition exists, the abnormal condition will be ignored. It has the same effect as the EXEC CICS IGNORE condition, except that it does not cancel the prior HANDLE CONDITION for any other command.

CICS Interview Questions for Experienced 

13. What are the classifications of the CICS program?

Ans. The following are some of the classifications of the CICS:

• Conversational programs
• Pseudo conversational programs
• Non Conventional programs

14. What are Non-conventional Programs?

Ans. Human intervention is not necessary when using Non-conventional programs. Non-conventional programs are identical to batch programs and likewise execute in batch mode. They are only used to display a sequence on the screen at regular intervals. 

15. What is a mapset?

Ans. A mapset is a group of maps that have been linked and altered to create a load module. There ought to be a PPT entry. Its names might be 1 to 7 characters long.

16. Define the CICS transaction initiation procedure.

Ans. Following is the CICS initiation procedure:

• TCP(transmission control protocol) stores data in TIOA(terminal input/output)  and creates corresponding entries in TCT(total cost technology). 
• KCP(Task Control program)  obtains the transaction identification from TIOA and checks to see if it exists in PCT.
• SCP acquires Storage in Task Control Area (TCA), where KCP creates task control data.
• KCP then looks for the application programs indicated in PCT in PPT and loads them. 
• Suppose there is no permanent storage memory location in the PPT. Control is passed to PCP(Program Control Program), which loads the application programs from the physical storage location address specified in the PPT.
• Control is subsequently transferred to the application software (LOAD module).

17. What exactly is MDT?

Ans. MDT is an abbreviation for Modified Data Tag.

• Only one attribute character is preserved.
• It has two values: 0 and 1.
• If it is 0, the terminal operator has not changed this field.
• If it is 1, the terminal operator has changed this field.
• If MDT is set to 1, data from the field is transferred from the terminal to the host computer.

18. Difference between TSQ and TDQ.

19. What is meant by program reentrance?

Ans. A program is termed reentrant if more than one task can run the code without interfering with the execution of the other processes. 

20. What is Quasi-reentrancy?

Ans. A program that is in a consistent condition upon entrance, before and after each EXEC CICS command is known as a quasi-reentrant program. 

21. What are the different forms of DFHMDF in the CICS?

Ans. The following are some of the DFHMDF kinds found in the CICS set:

• POS: In the CICS, POS stands for “position”. The POS parameter indicates the row and column position in the field about the map's upper left corner.
• Length: The length always represents the number of characters in the field. Because the attribute bytes are not present in length, each length will take one more column than its length value.
• ATTRB: ATTRB is an abbreviation for the field attribute. In most cases, the field attribute is optional in the BMS(Basic mapping support). This is because the BMS always employs the default settings for auto-skip protection, average intensity, and the customized tag.
• Initial: In the BMS, an initial is likewise not required. Only the initial in the label and title fields that already have a constant value in the BMS can be used.
• Picout: Picout is one of the filed CHG definitions. It helps inform the BMS about the primary types of images utilized to generate the fields. The Picout will also assist you in editing the COBOL(Common Business-Oriented Language) or PL/I facilities as you move the data into the map.
• GRPNAME and OCCURS: The GRPNAME and OCCURS options are usually absent from the simple example because they are among the most sophisticated forms. The GRPNAME is always used within the program to subdivide a map field for further processing, and the OCCURS is primarily used to define neighboring.

22. What are the primary applications of the transaction in the CICS?

Ans. The following are some of the applications of the transaction in the CICS:

• A transaction is a one-of-a-kind identifier primarily used to perform or initiate a specific job.
• A transaction is the type of four-character input, and no duplication is permitted, notably in transaction names.
• A transaction can be triggered by many systems simultaneously but not from the same system.
• A transaction will mostly have one-to-one or multiple mappings to the program that must be performed when the transaction trigger occurs.

23. What is the primary relevance of intra-partition and extra-partition TDQs?

Ans. CICS contains several batch areas, and particular datasets are primarily utilized for communication routes between CICS and batch regions outside CICS's domain.

• Extra-partition TDQs aid in the preceding step.
• Intra-partition TDQs, on the other hand, are communication channels within the CICS region. These channels are organized into several queues.

24.  Each map is divided into numerous fields, with three common working storage fields for each. Mention them?

Ans. In CICS, the three most frequent working storage fields are attribute, length, and output/input field. Without these three fields, the maps cannot be classified.

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25. Explain re-entry as it relates to CICS.

Ans. A reentrant program does not modify itself to reenter itself and continue processing after an interruption by the operating system, which executes other OS duties, including OS tasks of the same program, during the interruption. It is also a “reentrancy" or "reusable" program.

• A reentrant program in the CICS environment is a quasi-reentrant program.
• To put it another way, a quasi-reentrant program is a CICS program that does not modify itself. 
• That way, it can reenter and continue processing after an interruption by CICS. It executes other activities, including CICS tasks from the same program, during the interruption. A CICS application software must adhere to the following convention to sustain quasi-reentrancy:
  
  
  • Variable in Dynamic Working Storage: By issuing the CICS macro counterpart GETMAIN, the quasi-reentrant program dynamically acquires a unique storage space for each task. For each task, all variables will be placed in this DWS. After the DWS is obtained, all counters must be initialized.
  • Program Alteration Restrictions: The program may not change the program itself. If it modifies a CICS macro or command, it must restore the change before the following CICS macro or command.