CLASS Parameter

Purpose

The CLASS parameter in JCL specifies a job class for the job. It determines which job queue the job will be placed in, the processing priority it will receive, and often dictates resource limitations or special processing requirements. Job classes are defined by the installation and are used to categorize and manage workload.

Syntax

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//jobname JOB (accounting-information),programmer-name,CLASS=class

Format

CLASS is a keyword parameter on the JOB statement
class: A single alphanumeric character (A-Z, 0-9) or special character ($, #, @)
Installation-defined meaning for each class value
Default class is installation-defined, often 'A'

Examples

Basic Usage

jcl

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//PAYROLL JOB (ACCT123),'JOHN SMITH',CLASS=A

Submits the job to run in CLASS A

With Multiple Parameters

jcl

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//REPORT  JOB (ACCT456),'JANE DOE',
//             CLASS=B,MSGCLASS=X,NOTIFY=USER01

Submits the job to run in CLASS B with additional parameters

High Priority Job

jcl

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//URGENT  JOB (ACCT789),'OPS TEAM',CLASS=1,PRTY=15

Submits a high-priority job to run in CLASS 1 (typically for urgent processing)

Long-Running Batch

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//BIGBATCH JOB (ACCT321),'BATCH OPS',CLASS=L,TIME=1440

Submits a long-running job to a class for jobs with extended runtime (CLASS L)

Common Class Assignments

While these can vary by installation, common class assignments include:

Class	Typical Usage
A	Default class, short-running jobs
B	Medium-sized batch jobs
C	Compile jobs
P	Production jobs
L	Long-running jobs
T	Test jobs
0-9	Numeric classes often indicate priority (9 highest)

System Considerations

Classes are defined in JES2 initialization parameters (JES2PARM)
JES2: JOBCLASS(x) statement defines class attributes
JES3: CLASS statement defines class attributes
Certain classes may have special properties:
- Resource limits (memory, time)
- Execution priority
- Output handling
- SMF recording options
- System affinities (which system in a sysplex can run the job)

Notes

CLASS is an optional parameter on the JOB statement
If omitted, the default class is used (installation-defined)
The assigned class affects:
- Job scheduling priority
- Resource limits
- Execution characteristics
- Performance expectations
Classes may be held or released by operators
Some classes may only be available during certain time periods
Security systems may restrict which classes users can submit jobs to
WLM (Workload Manager) may use class for service level management

Common Mistakes

Using a class that doesn't exist in the installation
Using a class for which the user doesn't have authority
Specifying an inappropriate class for the job characteristics
Not understanding the resource limits associated with a class
Using a high-priority class for low-priority work

Related Concepts

JOB Statement - Contains the CLASS parameter
PRTY Parameter - Job priority, often used with CLASS
MSGCLASS Parameter - Controls job output class
SYSAFF Parameter - System affinity, may interact with CLASS
SCHENV Parameter - WLM scheduling environment