Mainframe Interview Questions and Answers

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Last updated

Feb 6, 2023

Mainframe testing is somewhat similar to web-based testing. It is actually defined and designed for mainframe system testing. It has a major role in application development. It comes into action to test the test case which is developed. To get into complete the complete details about the mainframe interview questions we are mentioning Questions and Answers that can be a help to you. Mainframe testing action usually takes place over the code which has already been deployed. Various sets of data combinations are used in the input file. A terminal emulator is usually used to access the applications running on the mainframe. The only thing that is required in the client’s system is Emulator installed in it. The tester must be aware of the CICS screen navigation while starting Mainframe testing.

You will get to about the complete details of Mainframe Testing in Mainframe interview questions that we are mentioning below.

Most Frequently Asked Mainframe Interview Questions

Here in this article, we will be listing frequently asked Mainframe Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

Q1. What is meant by DRDA?
Answer

DRDA means Distributed Relational Database Architecture, It is essentially a protocol for connection for relational database processing which many vendor databases and the IBM database use.

This is one of the most important mainframe developer interview questions.

Q2. What is the term “WHERE” for?
Answer

“WHERE” is a clause that is used which is meant to isolate a particular row or an element whenever it is used along with a relational statement

Q3. How do you create a LIKE table?
Answer

The LIKE table can be created It can be made by the use of the LIKE parameter in the statement CREATE. These tables are generally required for testing the production environment.

Q4. In a test environment, is there a need to run a runstats?
Answer

It is required to run a runstats because you have to clear the default values from the catalog columns. The existence of a default value in a column may result in an unexpected answer

Q5. Why do you need a secondary index in an IMS?
Answer

A secondary index is like an alternative path into any IMS database. It is a substitute path into any IMS database. It can be used as a file to acquire the required data.

Q6. Name the various types of tables spaces.
Answer

There are mainly three types of tablespaces

  • Simple
  • Segmented
  • Partitioned
Q7. What is the difference between HDAM and HIDAM databases?
Answer
HDAM database HIDAM database
HDAM databases do not have a separate index file. The key field in these files are passed through a randomizer and that places the record in its specific position in the database HIDAM databases have their own separate file indexes and they are based on the root segment. Each file has a piece of information about the pointer that shows the position of the data.
Q8. What is meant by referential integrity?
Answer

Referential integrity is a rule that states that there needs to be followed between the primary and foreign keys. This means that every foreign key needs to have a specific primary entry key

Q9. Explain the meaning of SPUFI
Answer

SPUFI stands for SQL Processing Using File Input. It is basically a tool driven by menus that the developers use to create objects in the database

Q10. What do you mean by an alias?
Answer

An alias is an alternative or a substitute to a synonym. They are created especially for distributed environments so that the developers can avoid using location qualifiers for tables or views.

Q11. Where is the VSAM KSDS placed?
Answer

The VSDM KSDS is placed at the BSDS. This question acts as a mainframe support interview question

Q12. List the type of locks and explain each of them.
Answer

There are primarily three types of locks:

  • Shared lock - The shared lock allows two or more programs to be read from the locked space itself but it does not allow the viewer to modify it
  • Update lock - It is a relatively more lenient type of lock, it slows the program to be read and it can also be modified
  • Exclusive lock - As the name states, it restricts any user to access the locked space and its contents
Q13. What is meant by an isolation level?
Answer

Isolation level is a degree by which the focused activation group is separated or isolated from the executed activation group at the same time is called an isolation level.

Q14. Name all the file-OPEN modes
Answer

There are four file OPEN modes, they are:

  • INPUT
  • OUTPUT
  • EXTEND
  • I-O
Q15. Is the order of the WHEN clause important in an EVALUATE statement? Is the order of the WHEN clause significant in an EVALUATE statement?
Answer

Yes, the order of the WHEN clause is significant in an EVALUATE statement. It has to take place from the top to the bottom and thereby, the order of the values has an effect on the results and may impact the outcome

Q16. Are scope terminators compulsory? If they are, when?
Answer

Scope terminators are mandatory for EVALUATE statements and in-line PERFORMS. These are always declared with complete transparency to improve its readability

Q17. What do you mean by linkage section?
Answer

The linkage is a part of a program that maps to the specific data in the program's working storage.

A linkage section is an area where any shared data item is defined and declared.

Q18. Explain how you can characterize tables in COBOL
Answer

The happens condition is used to characterize exhibits or tables in COBOL. The components of the table can be eluded by using INDEX or SUBSCRIPT

Q19. What is the usage of COMP fields in COBOL?
Answer

The COMP fields are usually used for the optimum utilization for speed and space handling for arithmetic operations

Q20. In which area will you utilize 88 level items in COBOL?
Answer

88 level items indicate restrictive factors and it helps in making choices for specific conditions in a program. You can use SET to increase the incentive for 88 level elements

Q21. Is it possible to move an alphanumeric incentive to a numeric field?
Answer

Yes, it is possible to move an alphanumeric incentive to a numeric field with a MOVE statement.

Q22. What is the difference between Delimited by size and Delimited by space?
Answer

When it comes to delimited by size, the delimiter is when you add up to the size of information in the field. When it comes to delimited by space, the space itself is the delimiter

Q23. What is meant by COMP-3 and what is it used for?
Answer

COMP-3 is used to share space and is a pressed decimal portrayal of information

Q24. Is it possible to move the alphanumeric variables to a numeric variable?
Answer

Yes, it is possible. If the field is used as part of the computation, you may face an information case problem (S0C7). This data provides a solution to COBOL queries with information development of many factors

Q25. What is INSPECT and what is it used for?
Answer

INSPECT is termed as a COBOL verb and it is used to discover the number of times a certain string shows up to supplant a certain segment of an information thing.

Q26. Can Min or Max be used with alphanumeric data?
Answer

Yes, you can use MIN or MAX with alphanumeric information

Q27. What is meant by deadlock in DB2?
Answer

A deadlock is a situation when an independent process is contended for a reserved or the same resource of one another. -911 and -913 are the SQL codes for a deadlock.

Q28. What is meant by a bolt dispute?
Answer

A bolt dispute is said to happen when an excess of one protest asks for consent for its execution simultaneously. The DBD passage only allows one question at a time

Q29. Explain a linkage segment
Answer

A linkage segment is a part of a program that maps to information things in the working stockpile of the program.

Q30. What is NEXT SENTENCE and CONTINUE unique?
Answer

NEXT SENTENCE is a code which handles the time frame and the stream of control into the statement. And the CONTINUE unique is responsible for the stream of control after the extension eliminator