Jcl stands for Job Control Statements

For your program to execute on the computer and perform the work you designed it

to do, your program must be processed by your operating system.

Your operating system consists of an MVS/SP base control program (BCP) with a

job entry subsystem (JES2 or JES3) and DFSMS/MVS DFSMSdfp installed with it.

For the operating system to process a program, programmers must perform certain

job control tasks. These tasks are performed through the job control statements,

which consist of:

JCL statements

JES2 control statements

JES3 control statements

Jobs

A job is a collection of related job steps. A job is identified by a JOB statement.

Job Steps

You enter a program into the operating system as a job step. A job step consists

of the job control statements that request and control execution of a program and

request the resources needed to run the program. A job step is identified by an

EXEC statement. The job step can also contain data needed by the program. The

operating system distinguishes job control statements from data by the contents of

the records.

Steps in a Job

A job can be simple or complex; it can consist of one step or of many steps that

call many in-stream and cataloged procedures. A job can consist of up to 255 job

steps, including all steps in any procedures that the job calls. Specification of a

greater number of steps produces a JCL error.

A JCL statement consists of one or more 80-byte records. Each record is in the

form of an 80-column punched-card image. Each JCL statement is logically divided

into the following five fields. All five fields do not appear on every statement

Identifier field

The identifier field indicates to the system that a statement is a JCL statement

rather than data. The identifier field consists of the following:

_ Columns 1 and 2 of all JCL statements, except the delimiter statement,

contain //

_ Columns 1 and 2 of the delimiter statement contain either /* or two other

characters designated in a DLM parameter to be the delimiter

_ Columns 1, 2, and 3 of a JCL comment statement contain //*

Name field

The name field identifies a particular statement so that other statements and

the system can refer to it. For JCL statements, code the name as follows:

_ The name must begin in column 3.

_ The name is 1 through 8 alphanumeric or national ($, #, @) characters.

_ The first character must be an alphabetic or national ($, #, @).

_ The name must be followed by at least one blank.

Operation field

The operation field specifies the type of statement, or, for the command

statement, the command. Code the operation field as follows:

_ The operation field consists of the characters in the syntax box for the

statement.

_ The operation follows the name field.

_ The operation must be preceded and followed by at least one blank.