Answering questions in front of your entire class was too difficult for you in your school or college days because you were not prepared at the time when the teacher or lecturer used to ask questions to you. Similarly, in an interview, you never know what an interviewer may ask you to judge your skills and expertise. However, with the help of our Mainframe interview questions and answers, it has just become easier for you to determine what are the questions usually asked in the interview and how to answer them appropriately so that you get the job that you are waiting for.
The mainframe is basically computers that are used primarily by large companies and organizations to perform critical tasks in complex applications. They use mainframe computers to process bulk data like census, consumer statistics, industry and market statistics, planning of enterprise resources, transactions processing, and lots more processes that deal with a huge amount of data. They are quite larger in size and have more amount of processing capabilities than servers, minicomputers, or any other workstations. These system architectures were introduced in the early 1960s but continued to develop for years together. These mainframe computers are often utilized as servers in these huge companies and organizations.
DRDA stands for Distributed Relational Database Architecture. It works as a connection protocol for local database processing. Database vendors like IBM use it. This architecture contains a set of rules that helps communicate between any application and database relation.
While working with a relational database system, the clause “WHERE” isolates an element or a row.
You can use the LIKE parameter and the CREATE statement to create the LIKE table. These tables are needed during the testing phase of the production environment.
The catalog columns are filled with default values and the end result during environment testing may not produce accurate results. Runstats is used to clear the default values of these columns.
It is a substitute path into any IMS database. It can be used as a file to acquire required data.
Foreign keys are properties of a particular table having matching entries to a primary key in some another table. This results in the formation of a relation between the two tables.
It limits the changes that can be made to the primary key from a foreign key. For this purpose, the foreign key has to define a DELETE CASCADE rule.
When two independent processes contend for the same resource or the resources reserved by one another, it is called a deadlock. -911 and -913 are the SQLcode for a deadlock.
It is used to access IMS files for CICS Transactions and it is an address space. PSBs, DBDs, IMS files and ACBs are fixed into DBCTL for file access. Now if an IMS call is generated by a CICS program the processing gets transferred to DBCTL to be carried, and the result is sent as reply.
TYPE 2 index is available for DB2V4. In this type, the data pages get locked, but the index pages are not locked. Therefore, TYPE 2 index are faster.
There are three table spaces, namely:
HIDAM has a separate index file which is based on the root segment. This file has information regarding the pointer that marks the position of the data. On the other hand, HDAM file does not have separate index file, but the key field of every record is passed through a randomizer which places the record to a particular position in the database.
It is the rule that states that consistency needs to be conserved between the foreign and primary keys. This means that each foreign key entry needs to have a fitting primary key entry.
Multiple index are two indexes, one each for a column of the same table. Composite index is only one index, which consists of combined values of 2 columns of a table.
It lowers the requirement for executing intensive relational joins. It also cuts the number of required foreign keys.
DBD, short for Database Descriptor, restricts access to the database when objects get altered, created or dropped.
Volumes can be inserted up to 133. Practically though, only 3-4 volumes, when added to an STOGROUP, becomes hard to manage and monitor.
Tables, which are related through a foreign key, are known as delete-connected tables. This is because whenever any entry in the primary key is deleted, it affects the values in the foreign key table too.
The DBD only allows entry to one object at a particular time. Lock contention is said to happen when more than one object seeks permission for execution simultaneously.
SPUFI is the abbreviated form of SQL Processing Using File Input. It is a menu-driven tool which the developers use to make objects in the database.
It is a substitute to a synonym. Aliases are developed for distributed environments so as to avoid the use of location qualifier of a view or table. It is not dropped when the table gets deleted.
It is the BSDS.
There are three types of lock, namely:
Custom fields are also known as post meta. Post meta is a feature in Mainframe which allows post authors to add additional information at the time writing a post. Mainframe stores this information as metadata in key-value pairs. Users can later display this metadata by using template tags in their Mainframe themes if required.
Isolation level is the degree to which the activation group in focus is isolated from the activation groups executing at the same time.
It is an MVS message that indicates the presence of a duplicate catalogue in the database. This problem can be fixed by removing one of the entries and then adding a new one.
JOBLIB is a Data Definition statement. It determines the location of the program, which called the EXEC statement. JOBLIB applies to all steps present in that whole job. It is not possible to use it for catalogued procedures. STEPLIB is very similar JOBLIB. It determines the dataset in which the program exists. It applies only to one step and not the entire job. STEPLIB can be used at any position in the job step and can also be used for catalogued procedures.
In a situation when both STEPLIB and JOBLIB are specified, JOBLIB will be ignored by the system.
In JES3, the allocation of data sets for the steps takes place even before the job is scheduled for execution. While in JES2, this allocation takes place just before the execution of each step.
The four File Open methods are:
With the growth in the computer industry sector over a period of time, mainframe computers are considered as the backbone for most of the companies who rely on servers. Although, all the companies rely on servers to carry out their daily tasks, however, it depends on the usage of the mainframe computers. Therefore, there are many companies who are hiring developers and system architects who are well-versed in handling these mainframe computers. Hence, the scope and opportunities for you getting a job are high. As a fresher, you can earn up to 78,000 dollars to 80,000 dollars per annum, and if you are experienced, then you can up to 163,000 dollars per annum.
There are a lot of scopes and opportunities for you to work in this specific sector if you want to pursue a career. However, cracking the interviews is the most difficult task, which can be dealt with if you follow our Mainframe interview questions and answers.