ALTERING GDG DEFINITION 5. DELETING GDG 6. IMPORTANT PRACTICAL QUESTIONS 1. INTRODUCTION Generation Data Groups or GDGs are a group. This facility is called Generation Data Groups (GDG). . There are two types of mainframe processes: Batch Processing Online Transaction Processing. JCL & VSAM: Hi all, I want to know the major difference between the dataset and GDG. reagrds akshatha.

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The preceding job that is described in Step 6 created an output file. The input used by this suite of programs is generated within the programs. Outdated or obsolete generations can be automatically deleted by the operating system. A typical mainfarme of events is to submit the jobs described in Steps to Enterprise Server and then review the results.

JCL Defining Datasets

Hence, the dataset is deleted when the job completes execution. GDG is created as the output. The operating system is able to keep the generations in chronological order. In a standardised JCL, the program to be executed and its related datasets are placed within a cataloged procedure, which is called in the JCL. Older data sets have smaller absolute numbers. Demonstrate how to access generations individual files within a group. The two zeroes on the end of the name are used to represent a volume number that is used when the file is stored on media requiring the use of multiple volumes.

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What is a GDG?

If the attributes and organizations of all generations in a group are identical, the generations can be retrieved together as a single data set. Explore the Glossary of Terms for a list of terms and definitions used in this suite of documents and white papers.


We reserve the right to make changes without notice at any time. Once the fee is received by SimoTime the latest version of the software, documentation or training material will be delivered and a license will be granted for use within an enterprise, provided the SimoTime copyright notice appear on all copies of the software. In that case, the dataset in the procedure can be overridden in the JCL.

This section includes links to documents with additional mainfrae that are beyond the scope and purpose of this document. If the attributes and organizations of all generations in a group are identical, the generations or individual data sets may be retrieved together as a single data set. An initial model DCB can be defined to be used by all versions, but it can be overridden when creating new versions.

The remaining generation data sets will be retained.

Software Agreement and Disclaimer. Process a Generation Data Group. Before you create the files that attach to a GDG base you may want to create a model dataset that contains the DCB information for the files. All of the data sets in the group can be referred to by a common name.

That is, each data set is historically related to the others in the group. The purpose of this suite of programs is to provide examples for creating and processing Generation Data Groups GDG’s.

The data will need to be transferred between the systems and may need to be converted and validated at various stages within the process. The SCRATCH parameter specifies that the oldest generation data set will be uncatalogued and deleted when the generation limit is exceeded.


The documentation and software were developed and tested on systems that are configured for a SIMOTIME environment based on the hardware, operating systems, user requirements and security requirements. If a user has a SimoTime Enterprise License the Documents and Program Suites may be available on a local server and accessed using the icon.

Submit the jobs described in steps and review the results.

Following is the syntax:. This suite of programs and documentation is available to download for review and evaluation purposes. For new non-system-managed data sets, if you do not specify a volume and the data set is not opened, the system does not catalog the data set.

The preceding job uses the IEFBR14 program a system supplied program that simply does a return to caller with a return code of zero in conjunction with a DD statement to create the model.

JCL – Defining Datasets

Program Input and Output. The document may be used assist as a tutorial for new programmers or as a quick reference for experienced programmers. SimoTime Technologies was founded in and is a privately owned company.

A good place to start is The SimoTime Home Page for access to white papers, program examples and product information. Quite often, to mainfraem larger markets or provide a higher level of service to existing customers it requires the newer Internet technologies to work in a complementary manner with existing corporate mainframe systems. Delete Functions, Use with Caution.