MainFrame
The term ‘MainFrame’ brings to mind a giant room of electronic parts that is a computer, referring to the original CPU cabinet in a computer of the mid-1960’s. Today, Mainframe refers to a class of ultra-reliable large and medium-scale servers designed for carrier-class and enterprise-class systems operations. Mainframes are costly, due to the support of symmetric multiprocessing (SMP) and dozens of central processors existing within in a single system. Mainframes are highly scalable. Through the addition of clusters, high-speed caches and volumes of memory, they connect to terabyte holding data subsystems.
The first mainframe vendors were GE, Control Data, IBM, NCR, RCA, Burroughs, Honeywell and Univac. Collectively known as “IBM and the Seven Dwarfs”. Through mergers, these vendors shifted within the industry, becoming “IBM and the BUNCH”. Running a version of Unix or Linux, these vendors led by IBM now include Amdahl (Fujitsu), Unisys and Sun among others.
Online training includes the History of Mainframes, Job Control Language (JCL) and thorough tutorials on the components, transactions and functions of the Customer Information Control System (CICS). Mainframe professionals can find well-paid work in highly respected and breakthrough technology companies throughout the world as Mainframe Systems Programmers and Project Managers.
CICS Overview and Functions CICS is called as Customer Information Control System. The main functionality of CICS is it acts as an interface between the Operating System and application programs. Functions of CICS Acts as interface between operating system and application programs. Does the function of data communication and therefore handle data. In other words CICS can support number of terminals or systems and acts as a data communication system between them. Take care of application program functions along with that take care of system functions also Also help in the task of monitoring Acts as a specialized operating system…
CICS Components and Transactions There are three major components associated with CICS namely Management Modules, Control Tables and Control Blocks. These three are very essential in CICS environment and so let us see an overview of the function of each. We have seen that CICS act as an interface between operating system and application program and this is achieved by management module. In other words Management Modules are programs that act as interface between operating system and application program. Control table is associated with management module and is used to define the CICS environment. A control block is used…
Customer Information Control System (CICS) In this tutorial you will learn about Customer Information Control System (CICS) – CICS – An overview, Functions of CICS, Task, Transaction and CICS Components. CICS – An overview CICS is called as Customer Information Control System. The main functionality of CICS is it acts as an interface between the Operating System and application programs. Functions of CICS Acts as interface between operating system and application programs . Does the function of data communication and therefore handle data. In other words CICS can support number of terminals or systems and acts as a data communication…
Introduction to JCL This article provides a basic coverage on concepts of MVS/JCL .The topics covered in this article are – Introduction to Job Control language, Basic concepts of JCL, Job & Job steps, Concepts of Job Statements and Positional & Keyword parameters. JES2/JES3 It is a Batch operating environment. In batch mode we submit or send processing request (JCL) to the system and then we can do some other tasks namely, one can read a book, do some other program etc. Our processing request is put into queue along with the line of other requests submitted by other people….
Mainframe Introduction In this Mainframe tutorial you will learn about mainframes and its concepts and some of the early mainframes describing the evolution and history of mainframes in detail. History and Evolution of Mainframes, Mainframe Channel, Direct Access Storage Device – DASD and Logical Partition – LPAR. What is Mainframe? As we all know the term mainframe when said to a layman would give a feeling of a large computer, but the question arise how large it is and what is the specialty of these mainframes. The answer to this question lies in the term "Mainframe" itself. As the name…
Mainframe Features In this Mainframe tutorial, you will learn about features of Mainframe – Processing power, memory capacity, performance, computing, multiple operating system, time sharing, reliability, serviceability, availability, clustering technology and other features available in Mainframe. Large Number of CPU with Greatest Processing Power: The mainframe has greatest processing capacity and to support this there is large number of CPU’s with high processing power embedded within the frame. Huge Memory Capacity: As explained before the mainframe applications takes its presence in large scale operations and to support this facility the memory capacity embedded within mainframe is very huge, in some…
VSAM Introduction In this Mainframe tutorial, you will learn about VSAM, what is VSAM, VSAM structure, types of VSAM datasets, Entry Sequenced Data Set (ESDS), Key Sequenced Data Set (KSDS), Linear Data Set (LDS) and Relative Record Data Set (RRDS). What is VSAM? VSAM stands for Virtual Storage Access Method. The VSAM is a method used for managing files in mainframe system. That is in other words VSAM is a data management system used in mainframe systems and this was introduced by IBM. VSAM also known as Virtual Storage Access Method is an access method for IBM’s mainframe operating system…
VSAM Catalogs In this Mainframe tutorial, you will learn about VSAM Catalogs, Master Catalog, User Catalog and Data Space of VSAM. Master Catalog Master Catalog in VSAM is like captain of a ship, since all files used in VSAM is controlled by this master catalog. The attributes of files like password authorization for files, monitoring of operation performed on files, VSAM access for files, location of the file, space management of file, available free space in file are all monitored, managed and present in Master catalog. The above attributes are maintained and updated as and when the attributes of files…
VSAM Structure In this Mainframe tutorial, you will learn about VSAM Structure, four major areas of VSAM structure, what is VSAM cluster, VSAM components, Defining VSAM cluster and Example for defining VSAM clusters. There are four major areas in the structure of VSAM. They are: The Master catalog The User catalog The Data space The file also called as cluster What is VSAM Cluster? VSAM dataset which we have seen in detail in our earlier section when defined logically takes up the form as a VSAM cluster. Before proceeding to see about VSAM cluster it is very important to know…
VSAM Control Interval and Control Area In this Mainframe tutorial, you will learn about VSAM Control Interval, What is a Control Interval in VSAM? and Control Area, what is VSAM control area, attributes in the control area index component. What is a Control Interval in VSAM? Control Interval in VSAM is a unit of data that is transferred when an I/O request is made between auxiliary storage and virtual storage. It contains records, free space and control information. The data records are grouped into control intervals. That is in other words in non-VSAM method the unit of data that is…
JES : Job Entry Subsystem In this MainFrame tutorial, you will learn about JES : Job Entry Subsystem, Job Scheduler, types of JES, HASP, ASP, Job management of MVS, General Phases in a Job viz Input, Conversion, Processing, Output, Print and Purge. Job Entry Subsystems: Job Scheduler: JES is an MVS component which keeps track of jobs that enter the system. The job entry subsystem also called as JES in short is used by MVS operating system. The JES is the component which presents jobs for MVS processing and sends the job’s spooled output back to the correct destination. A…
