Links To Wiki On Mainframe


MVS Operating System

Job Control Language




MQ Series


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COBOL Software Tools Directory 


Mainframes (often colloquially referred to as Big Iron) are computers used mainly by large organizations for critical applications, typically bulk data processing such as census, industry and consumer statistics, ERP, and financial transaction processing.

MVS Operating System - Multiple Virtual Storage

MVS (Multiple Virtual Storage) was the most commonly used operating system on the System/370 and System/390 IBM mainframe computers. It is unrelated to IBM's other mainframe operating system called VM/CMS.

First released in 1974, MVS was later renamed by IBM, first to MVS/XA (eXtended Architecture), next to MVS/ESA (Enterprise Systems Architecture), then to OS/390 when UNIX System Services (USS) were added, and finally to z/OS when 64-bit support was added on the zSeries models. Its core remains fundamentally the same operating system. By design, programs written for MVS can still run on z/OS without modification.

MVS descends from SVS (Single Virtual Storage), which in turn descends from MVT, one of the original variants of OS/360. The first variant of OS/360, PCP (Primary Control Program), did not support multitasking: one job (i.e. program, or task) occupied the machine's entire memory.
Job Control Language

Job Control Language (JCL) is a scripting language used on IBM mainframe operating systems to instruct the Job Entry Subsystem (that is, JES2 or JES3) on how to run a batch program or start a subsystem.

JCL is characterized by a pair of slashes "//" that indicate the start of each statement. The slashes date back from when punched cards were used to submit JCL code for execution. If the cards were mistakenly put back to front in the reader the slashes wouldn't be read first (instead, the sequence numbers would be), the card deck would be rejected.

For backward compatibility, the basic syntax of JCL for z/OS hasn't changed since the 1960s. It is the same as JCL for OS/360.

DOS/VSE also has a JCL language. Its syntax is entirely different, the only similarity being that statements still start with two slashes: "//".

- JCL For Programmers.doc

- JCL Training.doc

- JCL Users Manual.doc

COBOL (pronounced /kəʊbɒl/) is a third-generation programming language, and one of the oldest programming languages still in active use. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments.

The COBOL 2002 standard includes support for object-oriented programming and other modern language features.

DB2 is one of IBM's lines of relational database management system (or, as IBM now calls it, data server) software products within IBM's broader Information Management Software line. Although there are different "editions" and "versions" of DB2 which run on devices ranging from handhelds to mainframes, most often DB2 refers to DB2 Enterprise Server Edition or the top-of-the-line DB2 Data Warehouse Edition (DB2 DWE), which runs on Unix, Windows or Linux servers; or DB2 for z/OS. Beside DB2 there exists Informix which has been acquired by IBM in 2001.
CICS - Customer Information Control System

CICS (Customer Information Control System) is a transaction server that runs primarily on IBM mainframe systems under z/OS or z/VSE. CICS on distributed platforms is called TXSeries and it is available on AIX, Windows, Solaris and HP-UX. CICS is also available on other operating systems, notably i5/OS, OS/2. The z/OS implementation, ie, CICS Transaction Server for z/OS is by far the most popular and significant. It is known foremost as a pseudo-conversational computer application.

CICS is a transaction processing system designed for both online and batch activity. A transaction is basically a set of operations performing a task. Usually, the majority of transactions are relatively simple tasks such as updating the balance of an account. On large IBM zSeries and System z9 servers, CICS easily supports thousands of transactions per second, making it a mainstay of enterprise computing. CICS applications can be written in numerous programming languages, including COBOL, PL/I, C, C++, IBM Basic Assembly Language, REXX, and Java.
MQ Series

IBM WebSphere MQ is a network communication technology launched by IBM in March 1992. It was previously known as MQSeries, which is a trademark that was rebranded by IBM in 2002 to join the suite of WebSphere products. WebSphere MQ is IBM's Message Oriented Middleware offering. It allows independent and potentially non-concurrent applications on a distributed system to communicate with each other. MQ is available on a large number of platforms (both IBM and non-IBM), including z/OS (mainframe), UNIX (AIX, HP-UX, Solaris), HP NonStop, OpenVMS, Linux, and Microsoft Windows.
Introduction to Java Programming

Java is a programming language originally developed by Sun Microsystems and released in 1995. Java applications are typically compiled to bytecode, although compilation to native machine code is also possible. At runtime, bytecode is usually either interpreted or compiled to native code for execution, although direct hardware execution of bytecode by a Java processor is also possible.

The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities. JavaScript, a scripting language, shares a similar name and has similar syntax, but is not directly related to Java.

The original and reference implementation Java compilers, virtual machines, and class libraries were developed by Sun from 1995. As of May 2007, in compliance with the specifications of the Java Community Process, Sun made available most of their Java technologies as free software under the GNU General Public License. Others have also developed alternative implementations of these Sun technologies, such as the GNU Compiler for Java and GNU Classpath.


IBM Program Management Ver01.pdf