CICS Interview Questions & Answers

CICS (Customer Information Control System) is a family of mixed-language application servers that provide online transaction management and connectivity for applications on IBM mainframe systems under z/OS and z/VSE. CICS family products are designed as middleware and support rapid, high-volume online transaction processing. Here you will find the most commonly asked CICS interview questions with answers which are faced by interviewee. Also these questions will get you acquainted with the nature of the questions you may be ask during your interview.

1. What is CICS?

Answer:- CICS stands for Customer Information Control System. CICS was developed in 1968 by IBM. CICS allows users to develop and execute online application in an MVS environment. CICS has become the most commonly used server for Internet applications. CICS is a transaction processing system which is also called as Online Transaction Processing (OLTP) Software. CICS is a data communication system that can support a network containing hundreds of terminals.

2. What is the IBM 3270 Terminal?

Answer:- The 3270 terminals were a non-programmable or dumb workstation. It was a display screen with a keyboard attached to control.The 3270-terminal had basic text-based communications capabilities. he 3270 data stream operations are designed primarily for transmitting data between an application program and a 3270 display with keyboard so end users can interact with mainframe-based applications. Below are the components of IBM 3270 terminal :

1. CRT Monitor : The CRT monitor displays the output or the input fields of the application program. Monitor is capable of displaying 1920 characters (as shown in below diagram – 24 rows x 80 columns).
2. Keyboard : Every monitor in IBM 3270 terminal is connected with a keyboard to control the processing. IBM separated the keyboard keys into two categories –
    i) Non-AID Keys : All other keys for alphabets, numeric, punctuation etc. are Non-Aid keys. When the user types text or numbers using non-aid keys, CICS will not even know if the user is typing anything or not.
    ii) AID Keys : AID keys are known as Attention Identifier Keys. CICS can detect only AID keys. After typing all the input, only when the user presses one of the AID keys, CICS takes control. AID Keys : ENTER, PF1 to PF24, PA1 to PA3, CLEAR.

3. What is a Program control program (PCP)?

Answer:- Program control program (PCP) governs the flow between CICS and CICS application programs. Application program name must be registered in processing program table (PCT). If the program is not registered, it won’t be recognized by the CICS.
When the program execution is requested, PCP searches the program and load the program for execution if the entry is made in PCT. PCP responsible for transferring the control to the program and CICS during the execution.

4. What is CICS file control?

Answer:- CICS File Control lets you read, update, add and browse data in VSAM and BDAM data sets, and delete data from VSAM data sets. You can also access CICS shared data tables and pairing feature data tables by using File Control.
FCP makes application programs independent of the file structure. FCP manages the exclusive control over the records to maintain the data integrity during record updates.

5. What is Transaction?

Answer:- Transaction is unique identifier used start execution of a particular task. Transaction is a 4-characters entry and no duplicates will be allowed in transaction names.
Transaction will have one to one or one to many mappings with the programs that needs to be executed when the transaction triggered. Same transaction can be triggered concurrently from different terminals but not from the same terminal.

6. Differentiate between CESN and CEMT?

CESN : CESN is known as CICS Execute Sign On. CESN is used to Sign on to the CICS region. We need to provide the User-Id and Password given by the CICS administrator to log on to CICS.
CEMT : CEMT is known as CICS Execute Master Terminal. It is used to inquire and update the status of CICS environments and also for other system operations.

7. What is meant by COMMAREA?

Answer:- COMMAREA is the name of the data area in which the data or information transferred from one program to another program. The maximum length of the data can be passed through COMMAREA is 64K.
COMMAREA is an option of the LINK, XCTL, and RETURN commands. The LINK and XCTL commands COMMAREA option specifies the data area name in which data is passed to the program being invoked. The RETURN command COMMAREA option specifies the data area name in which data is passed to the transaction identified in the TRANSID option.

8. Can a CICS program call a batch program?

Answer:- You can call a batch program from a CICS program if the batch program has no file access or other routine that would have to be handled by CICS.

9. What is TSQ in CICS?

Answer:- A TSQ is a queue of records that can be created, read and deleted by different tasks or programs in the same CICS region. A queue identifier is used to identify TSQ. A record within a TSQ is identified by the relative position known as the item number. The records in TSQ, remains accessible until the entire TSQ is explicitly deleted.

10. How are unusual conditions handled in CICS?

Answer:- Exception Handling : Exceptional Condition is generated when a CICS command encounters an unusual situation. Task is abnormally terminated. An Abend code is displayed that identifies the exceptional condition.
Handling Exceptional Conditions Exceptions can be handled in three ways :
1. Pass control to a specified label.
2. Let the application continue.
3. Do nothing, and rely on the system (CICS) default action.

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