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Chapter 17: JCL Support

Mainframe Express enables you to build and test an MVS mainframe application on your PC up to the point where it is ready to be transferred to your mainframe system for final testing and production. You can also perform any subsequent maintenance of the application at a PC.

An important part of an MVS application is the JCL jobstream that controls its execution. Mainframe Express provides facilities to support the use of batch JCL jobstreams on the PC. Within the integrated development environment (IDE) of Mainframe Express, you can:

All mainframe operations require you to have installed and configured the relevant mainframe-access products.

A major objective of the JCL support is to keep the operations on the PC as similar as possible to those done on the mainframe. Thus on your PC, you can:

Much of the information in the chapter Running a TSO Session also applies to JCL support. We recommend that you read that chapter before using JCL. In addition, you need to understand more about the following topics:

Each of these topics is discussed below.

17.1 JCL Jobstreams

You can run the same JCL jobstreams on the PC as you can on the mainframe. Mainframe Express checks the JCL statements for errors as far as possible. Several parameters, especially on DD statements, have no meaning in a PC environment and are ignored at run time. This section describes the differences that apply when using JCL jobstreams in the Mainframe Express environment instead of the MVS mainframe environment.

17.1.1 JCL Features

Mainframe Express supports the following JCL features:

Mainframe Express does not support the following JCL features:

More information about the JCL statements supported by Mainframe Express is given later in this section.

Mainframe Express supports the running of JCL jobstreams either directly or via the TSO SUBMIT command and the Micro Focus extension ASUBMIT. You can run these TSO commands in a TSO session and with the IKJEFT01 utility.

Files containing JCL jobstreams and cataloged procedures can be downloaded from the mainframe or created on the PC. Cataloged procedures should be stored as members of partitioned data sets, known as procedure libraries. The procedure libraries are defined to Mainframe Express in two different ways:

Mainframe Express searches these libraries in the order specified above. Unlike the mainframe, you cannot define procedure libraries for an individual job (with the JOBLIB DD statement) or job step (with the STEPLIB DD statement).

If the JCL references a program (such as utility) which does not have a comparable PC version, you can replace the program name with the MFJBR14 utility. This utility simply executes a return to the caller, but other parts of the job step (such as data set allocation and disposition) are tested.

The jobstream is processed in three phases:

  1. When you click Done, after adding one or more JCL files to a project, Mainframe Express scans the JCL statements to resolve any dependencies on other files (such as cataloged procedures and statements included by INCLUDE statements).

  2. During a Build operation Mainframe Express scans the JCL statements to construct the jobstream, find any errors and extract the information that it requires to run the job. You can perform a Build operation:

  3. During a Debug operation, if the Build was successful, Mainframe Express runs each job step, taking into account any conditional statements (IF, THEN, ELSE) or conditional parameters (COND) that apply.

More details of the second and third phases are given later.

17.1.2 JCL Statements

For a full description of JCL statements, please refer to your IBM OS/390 MVS JCL Reference manual.

Mainframe Express supports the following JCL statements:

Statement
Description

DD

Defines the allocation and disposition of a data set

EXEC

Defines a job step, including the program or cataloged procedure to be run

JCLLIB

Specifies procedure libraries and their search order

JOB

Defines a job. Mainframe Express supports only one job per jobstream

INCLUDE

Specifies where pre-defined JCL statements are to be included in the jobstream

IF/THEN/ELSE/ENDIF

Specifies conditional execution of JCL statements

PROC

Defines the start of an instream JCL procedure

PEND

Defines the end of an instream JCL procedure

SET

Defines the values to be assigned to symbolic parameters

OUTPUT

Mainframe Express treats this as a DD statement

Mainframe Express does not support the following JCL statements. They are checked only for correct syntax.

Statement
Description

COMMAND

Issues commands to MVS and JES2

CNTL

Defines the start of a set of program control statements

ENDCNTL

Defines the end of a set of program control statements

XMIT

Transmits records from JES3

17.1.3 Scanning a Jobstream

Mainframe Express performs the following functions when it scans a JCL jobstream:

17.1.4 Running a Job Step

Mainframe Express performs the following functions when it runs a job step:

17.1.5 Running a Job on the Mainframe

You can submit to the mainframe jobs that you have created on the PC. Any JCL procedures used by the job must reside in a procedure library on the mainframe and you should include a suitable //PROC statement in the jobstream, such as:

//PROC JCLLIB ORDER=procedure-library

Any application programs used by the job must reside in a load library on the mainframe and you should include a suitable //JOBLIB statement in the jobstream, such as:

//JOBLIB DD DSN=load-library,DISP=SHR

17.2 Data Sets

Mainframe Express supports most mainframe data set organizations and record formats, as described in the chapter Advanced Data Set Information in your IDE Technical Guide.

Mainframe Express also supports temporary data sets and in-stream data sets included in the jobstream.

17.3 Application Programs

Mainframe Express emulates the interface between application programs and MVS in order to allocate data sets and pass parameters. These facilities are described below for COBOL programs. Similar rules apply to Assembler programs.

17.3.1 Allocating Data Sets

MVS provides a direct connection between the filename used in the program and the corresponding data set name used in the JCL. For example, for SYSUT1 in a COBOL program:

SELECT INFILE ASSIGN TO UT-S-SYSUT1

connects to

//SYSUT1 DD DSN=DSNAME1,DISP=OLD

and allocates to the program the PC file representing the data set named DSNAME1.

And, for SYSUT2:

SELECT OUTFILE ASSIGN TO UT-S-SYSUT2

connects to

//SYSUT2 DD DSN=DSNAME2,DISP=(NEW,CATLG),...

and allocates to the program a PC file representing the data set named DSNAME2. The file is created and cataloged automatically when the jobstream is run.

17.3.2 Passing Parameters

Parameters specified in the JCL PARM parameter are passed to the program using the same rules as the mainframe. For information on the linkage area that is used, see the chapter Running a TSO Session.


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