Mainframe CICS Interview Questions asked in companies like IBM, HP, Dell.
Explain what is a 2 phase commit in CICS?
Answer : Nornally, a two-phase commit ensures that all nodes in a distributed network have the same data. In a CICS/COBOL environment, the only time when it is needed is when there's a distributed database environment involved.
Can you tell me if there any entry for TSQs in CICS tables?Answer : Nornally, a two-phase commit ensures that all nodes in a distributed network have the same data. In a CICS/COBOL environment, the only time when it is needed is when there's a distributed database environment involved.
Answer : Yes, we have it in the DFHTST macro.
What is the use of Destination Control Table(DCT) in CICS?
Answer : In CICS, The DFHDCT macros are supported for migration purposes. Destination Control Table are used to define transient data destination. A destination can be extrapartition, intrapartition, remote or indirect.
What is ENQ, DEQ command?
Answer : ENQ and DEQ areTask control commands to make resources serially reusable, used to serialize access to a shared resource.
Can you use SQL COMMIT from a CICS program?
Answer : Yes, we can, however we should not use EXEC SQL COMMIT or EXEC SQL ROLLBACK commands.
Can you tell me what is the other way of terminating a transaction?
Answer : We can terminate it by using EXEC CICS SYNCPOINT. We have to assume it is a LUW. However, it will not end the Xn.
What is an AEY9 abend in CICS ? Answer : When DB2/IDMS is not up and running, the AEY9 is issued .
What are the conditions under which the command NEWCOPY is required ?
Answer : NEWCOPY brings in the recent load module into CICS region. Hence, when a program has been used in CICS at least once and then changed and recompiled, the command is required.
What is EXEC CICS RETRIEVE ?
Answer : RETRIEVE command retrieves data stored by expired START commands. Used by STARTed tasks to get the parameters passed to them.
What are some of the important fields in the EIB block ?
Answer : EIBTIME, EIBTASK, EIBCALEN, EIBRESP, EIBRRCDE, EIBDATE,
Can you use DYNAMIC calls in CICS ?
Answer : Yes, for this, the called routine must be defined in Processing program table and the calling program must use the CALL identifier. The COBPATH environment variable must be set properly.
How can you handle errors in CICS pgms ?
Answer : Check EIBRESP after the call or use the HANDLE condition.
How do you execute a background CICS txn ?
Answer : With a START or ATI.
Explain what is the difference between XCTL and START in CICS?
Answer : The command XCTL is used to pass control to a program within the same task and hence it is a program control command. The command START is used to start a new task, as such a interval control command.
What is the usage of language in the Processing program table entry?
Answer : Call parameters and Language interface.
Can you have CICS code in a copybook? If yes, what happens during compilation?
Answer : Yes, we can have CICS code in a copybook. It needs to be pre-processed.
What is an AICA abend in CICS?
Answer : If there is a transaction that terminated with abend code AICA, the transaction is most likely to have been in a loop.
Explain how would you resolve an ASRA abend?
Answer : In COBOL II start with CEBR, and get the offset/instruction.
Consider a transaction from CICS. The program has a code: MOVE DFHCOMMAREA TO WS-AREA. What happens to this transaction and other transactions?
Answer : In the current transaction, junk may get moved in. For other transactions, it will cause storage violation.
When you do a START, what is the value of EIBCALEN?
Answer : Zero.
How are VSAM files Read in CICS programs?
Answer : By using File Control Commands. They are Random, Sequential, forward and backward.
How would you access a VSAM file in CICS using an alternate index?
Answer : We can access a VSAM file through the path. Define path as an FCT and use normal File control commands.
Explain how can you rollback data written to an ESDS file?
Answer : For this you have to define the file as recoverable. There may be cases where records have been inserted into the file, you may need to run a batch program to logically delete the inserted records.
Can you access QSAM (seq ) files from CICS? Can you access ESDS files from CICS ?
Answer : QSAM (seq ) files cannot be accessed, but ESDS files can be accessed from CICS.
Finally, I want to ask you a very basic question which you should explain in detail. Explain what is CICS ?
Answer : CICS the abbreviated form of Customer Information Control System.
CICS is a telecom monitoring software from IBM. IBM mainframe OS comes either as batch and time-sharing. CICS itself is a batch job running on the operating system supports the development and execution of online applications.CICS achieves this by communicating with terminals and sending/receiving the formatted data - accessing files and the database. CICS also has got a important feature of scheduling of programs that run under the CICS region.
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