Running a TSO Session

REXX Support

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:

• Download jobstreams from the mainframe to the network server or PC

• Create new jobstreams at your PC

• Scan the jobstreams for syntax errors and dependencies

• Submit the jobstreams for running on the PC and view the spool output files

• Submit the jobstreams for running on the mainframe and view the spool output files

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:

• Use mainframe data set names in the jobstream, even though the data is held in a file on the PC

• Process jobstreams as if they were being run on the mainframe

• Use an output management system, similar to the mainframe's job entry system (JES), to view the SYSOUT listing and any other printed output produced by the jobstream

• View the spool output files in the same way irrespective of whether the jobs were run on Mainframe Express or the mainframe

• Use the functions of the many mainframe batch utilities

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:

• JCL jobstreams

• Data sets

• Application programs

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:

• Instream procedures

• Cataloged procedures

• Symbolic parameters

• EXEC statement overrides

• DD statement overrides

• Conditional execution (specified by IF, THEN, ELSE, and ENDIF statements)

• Job restart after execution failure

• Concatenated data sets

• Instream data sets (preceded by a DD * or DD DATA statement)

• Partitioned data sets

• Generation data groups

• Temporary data sets

• Comments (indicated by //*)

• Normal mainframe nesting limits (that is, 15 levels of nested procedures and 15 levels of nested INCLUDE statements)

Mainframe Express does not support the following JCL features:

• Multiple jobs in one jobstream

• Program control statements (enclosed by CNTL and ENDCNTL statements)

• Generated SYSIN DD * statements for instream data sets

• JOBLIB and STEPLIB DD statements

• All system DD statements used by IMS Option

• Other special DD statements that are not relevant to the PC or that are implemented differently by Mainframe Express. These statements have the following DD names:
  • JOBCAT

  • STEPCAT

  • SYSABEND

  • SYSMDUMP

  • SYSUDUMP

  • SYSCHK

  • SYSCKEOV

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:

• The libraries defined in the JCLLIB statement, for a single job

• The libraries defined to Mainframe Express, for all jobs. These libraries can be defined using Add Dependency Folder on the Workgroup View. Right-click the Dependency Libraries folder to see this.

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:
   • Explicitly, by selecting Scan or Rebuild All on the Build menu

   • Implicitly, when you request debugging, if a Build has not already been performed on the current version of the file

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:

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

17.1.3 Scanning a Jobstream

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

• Syntax checks the JCL statements for errors in the statement format, statement order, statement and parameter keywords. Checks the parameter values for each statement as indicated later in this section.

• For the JOB statement, checks all parameter values except the accounting information and programmer's name. It then extracts the job-name, message level (MSGLEVEL), message class (MSGCLASS), type of run (TYPRUN), restart step-name (RESTART) and any conditional expression (COND). A jobstream can contain only one job; a second JOB statement causes a JCL error and all subsequent statements are ignored.

• For each EXEC statement, checks all parameter values except ACCT. Extracts the program-name (PGM), any parameters to pass to the program (PARM) and any conditional expression (COND).

• For each DD statement, checks the values for the AMP, COPIES and RETPD parameters and the parameters from which it extracts the data set-name (DSN or DSNAME), SYSOUT class (SYSOUT), record format (RECFM or DCB=(RECFM)), logical record length (LRECL or DCB=(LRECL)), and data set disposition (DISP).

• Searches the procedure libraries for cataloged procedures, procedures specified by INCLUDE statements and resolves any symbolic parameters (on SET and PROC statements). A missing procedure causes a JCL error. Mainframe Express searches the procedure libraries in the following order:
  1. Libraries listed in the JCLLIB statement

  2. Libraries defined to Mainframe Express with Add Dependency Folder on the Workgroup View

• Includes instream procedures and resolves any symbolic parameters. An incorrect procedure causes a JCL error.

• Processes overrides to EXEC and DD statements in the normal way.

• Copies instream data, following a DD * or DD DATA statement, to a temporary data set. Ignores instream data that is not preceded by a DD * or DD DATA statement. On the mainframe, the system would automatically generate a SYSIN DD * statement.

17.1.4 Running a Job Step

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

• For the first job step in a job, assigns a job number and creates a spool file which can be viewed on the Spool View.

• Allocates any existing data sets (defined with DISP=SHR, OLD or possibly MOD).

  If Mainframe Express does not find a data set that is defined with DISP=SHR or OLD, the run terminates.

• Creates files for any new data sets (DISP=NEW or possibly MOD) and adds entries to the catalog

• Locates the program (by its actual name or an alias) by searching directories and procedure libraries in a predefined sequence.

• Constructs a linkage area for the PARM parameter, if specified, in the same way as on the mainframe and invokes the program.

• After the program has completed, retains data sets with DISP=KEEP, PASS or CATLG and deletes data sets with DISP=DELETE. In Mainframe Express, all data sets used by a job step are cataloged, thus KEEP and CATLG have the same meaning.

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.

Running a TSO Session

REXX Support