Mainframe Interview Questions and Answers

Mainframe Interview Questions and Answers

Mainframe Interview Questions : Mainframe computers (colloquially referred to as “big iron”) are computers used primarily by large organizations for critical applications; bulk data processing, such as census, industry and consumer statistics, enterprise resource planning; and transaction processing. They are larger and have more processing power than some other classes of computers: minicomputers, servers, workstations, and personal computers. The term originally referred to the large cabinets called “main frames” that housed the central processing unit and main memory of early computers. Later, the term was used to distinguish high-end commercial machines from less powerful units. Most large-scale computer system architectures were established in the 1960s but continue to evolve. Mainframe computers are acting as servers.

Several manufacturers produced mainframe computers from the late 1950s through the 1970s. The group of manufacturers was first known as “IBM and the Seven Dwarfs”:p.83 usually Burroughs, UNIVAC, NCR, Control Data, Honeywell, General Electric and RCA, although some lists varied. Later, with the departure of General Electric and RCA, it was referred to as IBM and the BUNCH.

IBM mainframes are large computer systems produced by IBM since 1952. During the 1960s and 1970s, the term mainframe computer was almost synonymous with IBM products due to their market share. Current mainframes in IBM’s line of business computers are developments of the basic design of the IBM System/360.


What is Mainframe?

What is Distributed Relational Database Architecture? And components?

Explain IBM Z?

What is Z/OS?

What is difference between static call and dynamic call?

What is Database Descriptor?

How do you find whether any generations exist under a GDG base?

What is use of linkage section?

How to get the last record in VSAM file in cluster? And how can u get the KSDs file records into COBOL program?

Write about the self-referencing constraint?

Can we give +2 instead of +1 while creating a new GDG file?

How JOINKEYS helps in SORT?

How are start and XCTL different?

What is difference between file-aid tool and file-aid utility?

Can you explain referential integrity?

How to find all duplicate records?

What is the function of the verb INITIALIZE?

Can you define Notcat 2?

How can we describe comp sync?

What difference exists between control area and control interval?

What is the difference between HIDAM and HDAM databases?

What is the need to code COMMITS in batch programs?

Can you define foreign keys?

Can you define an alias?

Can you define SPUFI?

Can you explain function of DBCTL?

Can you define path?

How to compare two files by using SORT?

Explain identify whether a CALL statement is a STATIC or DYNAMIC call?

Can you explain create an Empty file by using SORT?

What is SQLCA and why is it needed in any COBOL-DB2 program?

How an Empty file to be checked?

While creating a table, by mistake you have given size of one field as 10. But as per requirement size should be 8. What is your next step?

When is INSPECT verb is used in COBOL?

What is the difference between Goback, Stop Run and Exit Program in COBOL?

Can you explain function of IEBGENER?

What is the difference between INREC and OUTREC?

When do you get -811 SQLcode and how to resolve it?

How to handle -911 (deadlock) error in a db2 program so that the program will never ABEND?

What Optimum Values Can We Find for Freespace, Ci Etc?

How can we repair a soc-7 error?

Why is free space left in KSDS Dataset?

How are TYPE 1 and TYPE 2 indexes different?

Can you define a GDG?

How can we increment subscript and index?

What is label record is standard or omitted in file description of data division?

What are the Mainframe Computing Pros and Cons?