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Interview Questions and Answers

IDCAMS (Integrated Data Cluster Access Method Services) is a utility used for managing VSAM datasets. It can be used to create, delete, backup, and restore VSAM datasets.

Security considerations include access control, data encryption, intrusion detection, and compliance with security regulations. Its crucial to protect sensitive data and prevent unauthorized access.

A mainframe systems programmer is responsible for installing, configuring, and maintaining the mainframe operating system and related software. They also handle security, performance tuning, and problem resolution.

Career opportunities include mainframe programmer, systems programmer, database administrator, security specialist, and application developer. There is a growing demand for mainframe skills as many organizations still rely on these systems.

DB2 is IBMs relational database management system (RDBMS) for the mainframe. It provides a robust and scalable platform for managing structured data.

RACF is a security system used on IBM mainframes to control access to resources such as datasets, programs, and terminals. It provides authentication, authorization, and auditing capabilities.

Common tools include TSO/ISPF (Time Sharing Option/Interactive System Productivity Facility), SDSF (System Display and Search Facility), CA-Endevor (for change management), and debugging tools like Abend-AID.

TSO/ISPF is an interactive environment used for developing, testing, and maintaining mainframe applications. It provides a menu-driven interface for accessing various tools and utilities.

SDSF (System Display and Search Facility) is a tool used to monitor and manage mainframe jobs. It allows users to view job status, output, and system logs.

File transfer protocols like FTP (File Transfer Protocol), SFTP (Secure File Transfer Protocol), and utilities like IND$FILE are commonly used to transfer files between mainframes and PCs.

A PDS is a type of dataset that consists of a directory and one or more members. Each member can contain data or executable code. PDS is often used to store programs and load modules.

JCL is a scripting language used on IBM mainframes to instruct the operating system on how to execute a batch job. It defines the programs to run, the input data sets, and the output destinations.

Datasets are the fundamental units of data storage on a mainframe. They can be sequential files, partitioned datasets (PDS), or VSAM (Virtual Storage Access Method) datasets.

VSAM is a file access method used on IBM mainframes to provide efficient storage and retrieval of data. It supports various access methods, including sequential, direct, and keyed access.

CICS is a transaction processing system that allows applications to interact with users and databases in real-time. It provides a platform for managing online transactions and applications.

IMS is a hierarchical database and transaction management system. It is used for managing large databases and supporting high-volume transaction processing.

A mainframe computer is a large, powerful computer primarily used by organizations for critical applications, typically for bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and transaction processing.

Key characteristics include high processing capacity, reliability, security, availability, and scalability. Mainframes are designed to handle large volumes of data and transactions efficiently.

The most common operating system is z/OS, developed by IBM. Others include z/VM, z/VSE, and Linux on IBM Z.

COBOL (Common Business-Oriented Language) is a programming language designed for business applications. Its still used on mainframes because many critical business systems were built with COBOL and continue to function reliably.

Mainframes are high-performance computers with large amounts of memory and processors that process billions of simple calculations and transactions in real time. The mainframe is critical to commercial databases, transaction servers, and applications that

Advantages of mainframe computer - Reliability, availability and serviceability.
High-end scalability
Security
Long-lasting performance
Continuing compatibility
Huge memory storage
Virtualization
Can run multiple OS<

DRDA - Distributed Relational Database Architecture. It is a connection protocol for relational database processing which IBM and vendor databases use. It consists of rules for communication between a remote relational DBMS and the application.

DC

LINKAGE SECTION defines the data items to receive the data from called program to the current program by using CALL. LINKAGE SECTION also defines the data items to receive the data from JCL through PARM operand.

An aggregate function accepts arguments and returns a single scalar value that is the result of an evaluation of a set of like values, such as those in a column within a set of one or more rows. The argument of an aggregate function is a set of values der

CICS can access DL/I databases with the CICS-DBCTL interface

VSAM performs better than DB2 when amount of data accessed by a task is less. But DB2 can perform better than VSAM when large amount of data is used by application.

Index Cardinality is defined as the number of distinct values of column(s) that make up a given index.

JCL

INCLUDE is executed at pre-compile time (by the SQL compiler), COPY is executed at compile time(by the COBOL compiler).

EVALUATE - EVALUATE statement is used for conditional processing which helps in avoiding a series of nested IF statements to test several conditions.

OCCURS - OCCURS clause specifies tables where elements can be referred by indexing or subscripting

DB2 imposes locks of four differing sizes: pages, tables, tablespace and for indexes subpage.

In Db2, an application program uses a cursor to point to one or more rows in a set of rows that are retrieved from a table. You can also use a cursor to retrieve rows from a result set that is returned by a stored procedure.

To run a program using Db2, you need a Db2 plan. The bind process creates the Db2 plan. Db2 first verifies whether the DL/I batch job step can connect to Db2. Then Db2 verifies whether the application program can access Db2 and enforce user identification

Through the RESTART parameter

Entry sequenced datasets (ESDS), Key sequenced datasets (KSDS), Relative record dataset (RRDS) and Linear dataset (LDS).

You can use symbolic cursor positioning instead of coding an explicit value on the CURSOR option of the EXEC CICS SEND MAP command. To do this: Specify MODE=INOUT in the DFHMSD macro. Set the length of the field (to which the cursor is to be positioned) t

It brings the entire datastream from the terminal buffer.

Explain with examples that sync with the job description.

Model–view–controller(MVC) is a software design pattern used for developing user interfaces that separate the related program logic into three interconnected elements. Each of these components is built to handle specific development aspects of an applicat

Explain specific instances with respect to the job JD.

Software testing is called the process or method of identifying errors in an application or system, such that the application works according to the requirement of end-users. It is an examination carried out to provide users the information on the quality

Explain specific instances with respect to the job JD.

The primary aim of the code review is to ensure that the codebase overall product quality is maintained over time. It helps give a fresh set of eyes to identify bugs and simple coding errors. All of the tools and processes of code review are designed to t

The most common software sizing methodology has been counting the lines of code written in the application source. Another approach is to do Functional Size Measurement, to express the functionality size as a number by performing Function point analysis.

Basecamp, Teamwork Projects, ProofHub, Zoho Projects, Nifty, Trello, JIRA, Asana, Podio, etc.

Functional requirements are the specifications explicitly requested by the end-user as essential facilities the system should provide. Non-functional requirements are the quality constraints that the system must satisfy according to the project contract,

Validation is the process of checking whether the specification captures the user's needs, while verification is the process of checking that the software meets the specification.

Different Types Of Software Testing - Unit Testing, Integration Testing, System Testing, Sanity Testing, Smoke Testing, Interface Testing, Regression Testing, Beta/Acceptance Testing.

Quality control can be described as part of quality management that is focused on fulfilling quality requirements. While quality assurance relates to how a process is performed or how a product is made.

Single Responsibility Principle (SRP), Open/Closed Principle (OCP), Liskov Substitution Principle (LSP), Interface Segregation Principle (ISP), Dependency Inversion Principle (DIP).