---
title: "JCL GDG Required and Optional Parameters"
description: "Top parameters you need to give while using GDGs in a JCL"
url: https://srinimf.com/2015/12/19/jcl-gdg-required-and-optional-parameters/
date: 2015-12-19
modified: 2022-11-16
author: "Srini"
image: https://i0.wp.com/srinimf.com/wp-content/uploads/2015/12/jcl-parameters1.jpg?fit=1200%2C900&ssl=1
categories: ["JCL"]
tags: ["GDG Interview Questions", "How to create GDG in JCL"]
type: post
lang: en
---

# JCL GDG Required and Optional Parameters

The below is the list of GDG parameters that used in across different projects.

**Required:**

The below parameters are mandatory.

**NAME(entryname****)** Specifies the name of the GDG being defined.

**LIMIT(limit) **Specifies the maximum number, from 1 to 255, of GDSs that can be associated with the GDG being defined.

**Default parameters:**

NOEMPTY and SCRATCH are default parameters.

**Optional:**

**EMPTY** remove all GDS entries from GDG base when a new GDS is created that causes the GDG LIMIT to be exceeded.

**NOEMPTY** remove only the oldest GDS entry when a new GDS is created that causes GDG LIMIT to be exceeded.

**EXTENDED** allow up to 999 generation data sets (GDSs) to be associated with the GDG.

**NOEXTENDED** allow up to 255 generation data sets (GDSs) to be associated with the GDG. This is the default value.

**FIFO **The order is the oldest GDS defined to the newest GDS.

**LIFO** The order is the newest GDS defined to the oldest GDS. T**his is the default value.**

**Related:** **[Difference between GDG generation(+1) Vs Generation (+2).](http://srinimf.com/2015/11/29/ultimate-answer-for-gdg-1-vs-gdg-2-generation-in-jcl/)**

**PURGE|****NOPURGE** Specifies whether to override expiration dates when a generation data set (GDS) is rolled off and the SCRATCH parameter is set.

PURGE will override the expiration date and cause the VTOC entry to be deleted regardless of the expiration date.

** PURGE** is ignored when NOSCRATCH is specified, either explicitly or as the default.

The default **NOPURGE** can be changed with the Catalog parmlib member (IGGCATxx) variable GDGPURGE.

**SCRATCH|****NOSCRATCH** Specifies what action is to be taken for a generation data set located on disk volumes when the data set is uncataloged from the GDG base as a result of EMPTY/NOEMPTY processing. For generation data sets located on tape, this parameter has no effect.

You can override the SCRATCH|NOSCRATCH attribute when issuing the DELETE command.

**SCRATCH**The GDG is deleted from all disks it occupies when uncataloged from the GDG base, regardless of whether it is SMS-managed or not.

**NOSCRATCH**If the data set is a non-SMS managed data set it is not removed from any of the volumes it occupies. If the data set is an SMS-managed data set it is recataloged as a non-VSAM data set in rolled-off status, and is no longer associated with the GDG base. It is not deleted from any of the SMS-managed volumes it occupies.

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