MainFrames Interview Questions

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If you're looking for MainFrames Interview Questions for Experienced or Freshers, you are in right place. There are a lot of opportunities from many reputed companies in the world. According to research MainFrames has a market share of about 1.8%. So, You still have the opportunity to move ahead in your career as MainFrames Developer. Mindmajix offers Advanced MainFrames Interview Questions 2024 that helps you in cracking your interview & acquire a dream career as MainFrames Developer.

Following are the topics we will be covering in this article

Top 5 Frequently Asked Mainframe Interview Questions

1) What is DRDA?

2) What is the utilization of the Linkage area in COBOL?

3) What is the distinction between INCLUDE and COPY?

4) What is the contrast between Delimited by Space and Delimited by Size?

5) What is the function of the DBCTL?

Mainframe Interview Questions for Freshers

1) What is DRDA?

DRDA means Distributed Relational Database Architecture. It is a connection protocol that is used for local database processing. IBM and other vendor databases use it. It contains a set of rules which is used for communication between an application and a DBMS distant relation.

2) Define WHERE and its usage?

The clause "WHERE" isolates a row or an element during the usage of a related system.

3) Define how the LIKE table could be created?

The usage of the LIKE parameter could create the LIKE table by the CREATE statement. These tables are usually required during the testing of the production environment.

4) Define the necessity of runstats among the environment test?

It is used for the clearing of the different values of the catalog columns. Since this column is already equipped with default values, the end result may not be as expected.

5) What is the utilization of the Linkage area in COBOL?

Linkage area is utilized as a part of COBOL if the program needs to speak with JCL by means of PARM parameter or program needs to speak with another program.

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6) What is the utilization of COPYBOOK in COBOL? Would we be able to utilize a similar?

COPYBOOK spares the format of any record and uses a similar design over any program. Indeed, we can elude the same copybook for various documents if the format is same and REPLACING choice is to be utilized alongside COPYBOOK for that.

7) What is the distinction between INCLUDE and COPY?

A minimal distinction is there in the way they work. They both help to extend design in a program.  The central contrast is INCLUDE gets extended at PRE-COMPILATION organize itself and is the motivation behind why all DCLGEN individuals are extended utilizing INCLUDE.

8) How to characterize tables in COBOL?

Happens condition is utilized to characterize tables or exhibits in COBOL. Table components can be eluded by utilizing either SUBSCRIPT or INDEX.

9) How do COMP fields help in COBOL?

COMP fields, for the most part, utilized for ideal utilization of room and for speed handling of arithmetic activities.

10) Where do you utilize 88 level things in COBOL?

88 levels are uncommonly implied for restrictive factors and take choices in view of specific conditions in a program. We can utilize SET to dole out an incentive to 88 level variables.

11) Can we move the Alphanumeric incentive to the Numeric field?

Indeed, we can move, and it won't make any issue as long it is just a MOVE statement. But the program may bomb some of the time in case the field is in utilized as a part of number-crunching computations.

12) How EVALUATE helps in COBOL?

Assess is utilized as a part of restrictive preparing, and it disentangles the way we compose IF – ELSE explanations.

13) How to distinguish whether a CALL proclamation is a STATIC or DYNAMIC call?

On the off chance that the program name is eluded explicitly in the CALL articulation then it is considered as a Static call and if a working stockpiling variable alludes in the CALL explanation then it is considered as a Dynamic call.

14) How TEST BEFORE/AFTER works with PERFORM UNTIL explanation in COBOL?

With TEST AFTER, Perform articulations are handled and after that conditions are checked. With TEST BEFORE, Condition is checked first, and afterward, in light of the outcome Perform explanations are prepared.

15) When is INSPECT verb is utilized as a part of COBOL?

Investigate is utilized to know the number of times a particular character happens or to supplant some bit of information.

16) How the number of juggling tasks is performed in COBOL?

We can do a wide range of number juggling activities in COBOL.

17) State the difference between GOBACK, STOP RUN, and EXIT PROGRAM in COBOL?

The fundamental differences between GOBACK, STOP RUN, and EXIT PROGRAM in COBOL are:

  • GOBACK returns control to the calling program

  • STOP RUN stops the present work unit and returns control to OS

  • EXIT PROGRAM is utilized to leave a program that has been called by another program

18) What is the contrast between Delimited by Space and Delimited by Size?

In delimited by Space, Space is considered as a delimiter. In delimited by measure, add up to the size of information thing is considered as a delimiter.

19) Define COMP - 3 fields and their utilization?

COMP-3 is a pressed decimal portrayal of information and is utilized to spare space.

20) Can the values of alphanumeric be moved to variable numeric?

Truly, it can be done. May confront particular information case (S0C7) blunder in the event that if the field is utilized as a part of any computation. This data answers COBOL inquiries questions identified with information development of various sort of factors.

Mainframe Interview Questions for Experienced 

21) Define INSPECT along with its utilization?

Investigate is a characterized COBOL verb, and it is utilized to discover number per times a specific string or character shows up or to supplant some segment of any information thing.  For finish data on the best way of working with INSPECT and COBOL inquiries on INSPECT in COBOL,

22) Can we utilize Min or Max along with the alphanumeric information?

Yes, MAX or MIN can be utilized with alphanumeric information. 

23) How to discover when COBOL program was gathered?

We can discover by utilizing WHEN-COMPILED work or via looking through the library LOAD. There is a characterized work in COBOL that can be utilized to discover the arrangement of the date and the time of any given program. The capacity is utilized during WHEN-COMPILED while it returns the 21 characters.

  • Test:

    Technique division proclamation:


  • Yield:

    PROGRAM COMPILED ON 2013122412433857+0000

    This data answers COBOL inquiries questions identified with the program assemblage.

24) Define the procedure to pass an incentive from JCL to COBOL?

  • We can go by utilizing RETURN-CODE.

  • There’s a characterized word RETURN-CODE in COBOL that can be utilized to pass information from the program to the JCL. This is particularly valuable when some particular return code is accounted for in an occupation.

  • Typically the activity returns 0 or 4 or in some cases 8 or 12 return code if any irregularity happens. This can be changed by utilizing the RETURN-CODE of the program. This data answers COBOL inquiries questions identified with passing information from COBOL to JCL.

25) Define DELIMITED BY SPACE and DELIMITED BY SIZE along with their utilization?

DELIMITED BY SPACE or DELIMITED BY SIZE will be utilized alongside the STRING for controlling the information in case it is replicated.

  • DELIMITED BY SIZE: Total size of information things would be considered as the delimiter,

  • DELIMITED BY SPACE: Space would be considered as the delimiter

26) What are the situations which can bring about an Infinite circle by utilizing PERFORM?

With PERFORM TIMES and PERFORM UNTIL a large circle can be created.

27) Define the utilization of TEST BEFORE as well as TEST AFTER in the PERFORM explanations?

TEST BEFORE and TEST AFTER are utilized to characterize when the condition to be checked.

28) Define deadlock in DB2?

When there is an independent process that gets contended for the same or reserved resource of one another, that is when it is called deadlock. The SQL codes for deadlock are -911 and -913.

29) What is the function of the DBCTL?

DBCTL is used for accessing the IMS filed for the CICS transactions, and they are fixed in the DBTCL for accessing files. Now in case, it is an IMS call that is generated by the CICS programs, then the processing is transferred to be carried by the DBCTL and a reply is sent as an outcome.

30) Differentiate Between HDAM and the HIDAM databases?

HIDAM is a separated index file that is based on the segmented root. The HIDAM is equipped with the information of the pointers that are based on the marks of the position of the data. While on the other hand, the HDAM has separated index files, but, all the key fields of the very records are passed through a random which places the records of a particular position of the databases.

31) Clarify bolt dispute?

The DBD enables passage to one question at a specific time. Bolt conflict is said to happen when in excess of one protest looks for consent for execution at the same time.

32) Define SPUFI?

SPUFI is an abridged type of SQL Processing Using File Input.  It's a menu-driven instrument which the designer uses for making objects in the database.

33) Define Alias?

It is auxiliary to an equivalent word. Nom de plumes are produced for appropriated situations in order to maintain a strategic distance from the utilization of the area frontrunner of a view or table. It isn't released when the table is erased.

34) Define the place of a VSAM KSDS?

The place of a VSAM is in the BSDS.

35) Name and clarify the sort of locks?

Typically, there are 3 sorts of LOCKS in particular:

  • Shared – This sort of bolt allows at least two projects to peruse from the bolted space, however, does not enable them to transform it.
  • Refresh – This bolt is more indulgent. It allows the program to peruse and change the bolted space.
  • Selective – This bolt confines all clients from getting to the bolted space.

36) Clarify confinement level?

Confinement level is how much the initiation assembles in the center if it is disconnected from the actuation bunches executing in the meantime.

37) Define NOTCAT2?

It remains a VMS note that demonstrates the nearness of a copy inventory in the database. This issue can be settled by evacuating one of the passages and after that including another one.

38) What will happen if both STEPLIB and JOBLIB are determined?

JOBLIB is a Data Definition proclamation. It decides the area of the database, which is called the EXEC articulation. JOBLIB is applicable to all means introduce in that entire employment. It isn't conceivable to utilize it for detailed methodology. STEPLIB is fundamentally the same as JOBLIB. It decides the dataset within which this program exists. It applies to just one stage, not the total employment. STEPLIB could be utilized in any situation in the action step and also can likewise be utilized for detailed methodology.
In a circumstance when both the STEPLIB and JOBLIB are indicated, the JOBLIB will be overlooked by the framework.

39) Express the distinction between JES2 and JES3?

In the JES3, the distribution of informational indexes for the means happens prior to the activity is planned for executing. While in the JES2, this assignment happens prior to the execution of each progression.

40) Express all of the OPEN file modes?

The 4 File Open strategies are:

  • Information
  • Yield
  • Broaden
  •  I-O

41) Is the request of the WHEN clause critical in an EVALUATE proclamation?

Truly, the request is critical as the assessment happens in the through and through way and, hence, the request has a vast effect on the assurance of results.

42) At what point are extension eliminators mandatory?

They are obligatory for EVALUATE articulations along with the in-line PERFORMS. Extension eliminators are announced continuously unequivocally to enhance intelligibility.

43) Define linkage segment?

It is a piece of the program which is being called and also maps to information things in the program's (calling) working stockpiling. Linkage Sections are the places where shared things are pronounced and characterized.

44) Define NEXT SENTENCE and the CONTINUE unique?

The NEXT SENTENCE handles the stream of control into the statement that takes the following time frame. Then again, CONTINUE handles the stream of control of the following articulation after the extension eliminator.

About Author

Ravindra Savaram is a Technical Lead at His passion lies in writing articles on the most popular IT platforms including Machine learning, DevOps, Data Science, Artificial Intelligence, RPA, Deep Learning, and so on. You can stay up to date on all these technologies by following him on LinkedIn and Twitter.

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