JCL - Overview
When to use JCL
JCL is used in a mainframe environment to act as a communication between a program (Example: COBOL, Assembler or PL/I) and the operating system. In a mainframe environment, programs can be executed in batch and online mode.Example of a batch system can be processing the bank transactions through a VSAM (Virtual Storage Access Method) file and applying it to the corresponding accounts. Example of an online system can be a back office screen used by staffs in a bank to open an account. In batch mode, programs are submitted to the operating system as a job through a JCL.
Batch and Online processing differ in the aspect of input, output and program execution request. In batch processing, these aspects are fed into a JCL which is in turn received by the Operating System.
Job Processing
A job is a unit of work which can be made up of many job steps. Each job step is specified in a Job Control Language (JCL) through a set of Job Control Statements.The Operating System uses Job Entry System (JES) to receive jobs into the Operating System, to schedule them for processing and to control the output.
Job processing goes through a series of steps as given below:
- Job Submission - Submitting the JCL to JES.
- Job Conversion - The JCL along with the PROC is converted into an interpreted text to be understood by JES and stored into a dataset, which we call as SPOOL.
- Job Queuing - JES decides the priority of the job based on CLASS and PRTY parameters in the JOB statement (explained in JCL - JOB Statement chapter). The JCL errors are checked and the job is scheduled into the job queue if there are no errors.
- Job Execution - When the job reaches its highest priority, it is taken up for execution from the job queue. The JCL is read from the SPOOL, the program is executed and the output is redirected to the corresponding output destination as specified in the JCL.
- Purging - When the job is complete, the allocated resources and the JES SPOOL space is released. In order to store the job log, we need to copy the job log to another dataset before it is released from the SPOOL.
JCL - Environment Setup
Installing JCL on Windows/Linux
There are many Free Mainframe Emulators available for Windows which can be used to write and learn sample JCLs.One such emulator is Hercules, which can be easily installed in Windows by following few simple steps given below:
- Download and install the Hercules emulator, which is available from the Hercules' home site - : www.hercules-390.eu
- Once you installed package on Windows machine, it will create a folder like C:\Mainframes.
- Run Command Prompt (CMD) and reach the directory C:\Mainframes on CMD.
- The complete guide on various commands to write and execute a JCL can be found on URL www.jaymoseley.com/hercules/installmvs/instmvs2.htm
Running JCL on Mainframes
A user can connect to a mainframe server in a number of ways such a thin client, dummy terminal, Virtual Client System (VCS) or Virtual Desktop System (VDS).Every valid user is given a login id to enter into the Z/OS interface (TSO/E or ISPF). In the Z/OS interface, the JCL can be coded and stored as a member in a Partitioned Dataset (PDS). When the JCL is submitted, it is executed and the output received as explained in the job processing section of previous chapter.
Structure of a JCL
The basic structure of a JCL with the common statements is given below://SAMPJCL JOB 1,CLASS=6,MSGCLASS=0,NOTIFY=&SYSUID (1) //* (2) //STEP010 EXEC PGM=SORT (3) //SORTIN DD DSN=JCL.SAMPLE.INPUT,DISP=SHR (4) //SORTOUT DD DSN=JCL.SAMPLE.OUTPUT, (5) // DISP=(NEW,CATLG,CATLG),DATACLAS=DSIZE50 //SYSOUT DD SYSOUT=* (6) //SYSUDUMP DD SYSOUT=C (6) //SYSPRINT DD SYSOUT=* (6) //SYSIN DD * (6) SORT FIELDS=COPY INCLUDE COND=(28,3,CH,EQ,C'XXX') /* (7)
Program Description
The numbered JCL statements have been explained below:(1) JOB statement - Specifies the information required for SPOOLing of the job such as job id, priority of execution, user-id to be notified upon completion of the job.
(2) //* statement - This is a comment statement.
(3) EXEC statement - Specifies the PROC/Program to be executed. In the above example, a SORT program is being executed (i.e., sorting the input data in a particular order)
(4) Input DD statement - Specifies the type of input to be passed to the program mentioned in (3). In the above example, a Physical Sequential (PS) file is passed as input in shared mode (DISP = SHR).
(5) Output DD statement - Specifies the type of output to be produced by the program upon execution. In the above example, a PS file is created. If a statement extends beyond the 70th position in a line, then it is continued in the next line, which should start with "//" followed by one or more spaces.
(6) There can be other types of DD statements to specify additional information to the program (In the above example: The SORT condition is specified in the SYSIN DD statement) and to specify the destination for error/execution log (Example: SYSUDUMP/SYSPRINT). DD statements can be contained in a dataset (mainframe file) or as in stream data (information hard-coded within the JCL) as given in above example.
(7) /* marks the end of in stream data.
All the JCL statements except in stream data starts with //. There should be at least one space before and after JOB, EXEC and DD keywords and there should not be any spaces in rest of the statement.
JOB Parameter Types
Each of the JCL statements is accompanied by a set of parameters to help the Operating Systems in completing the program execution. The parameters can be of two types:Positional Parameters
- Appears at pre-defined position and order in the statement. Example: Accounting information Parameter can appear only after the JOB keyword and before the programmer name parameter and the Keyword Parameters. If a positional parameter is omitted, it has to be replaced with a comma.
- Positional Parameters are present in JOB and EXEC statements. In the above example, PGM is a positional parameter coded after the EXEC keyword.
Keyword Parameters
- They are coded after the positional parameters, but can appear in any order. Keyword parameters can be omitted if not required. The generic syntax is KEYWORD= value. Example: MSGCLASS=X, i.e., the job log is redirected to the output SPOOL after the job completion.
- In the above example, CLASS, MSGCLASS and NOTIFY are keyword parameters of JOB statement. There can be keyword parameters in EXEC statement as well.
JCL - JOB Statement
JOB Statement is the first control statement in a JCL. This gives the identity of the job to the Operating System (OS), in the spool and in the scheduler. The parameters in the JOB statement help the Operating Systems in allocating the right scheduler, required CPU time and issuing notifications to the user.Syntax
Following is the basic syntax of a JCL JOB statement://Job-name JOB Positional-param, Keyword-param
Description
Let us see the description of the terms used in above JOB statement syntax.Job-name
This gives an id to the job while submitting it to the OS. It is can be length of 1 to 8 with alphanumeric characters and starts just after //.JOB
This is the keyword to identify it as a JOB statement.Positional-param
There are positional parameters, which can be of two types:| Positional Parameter | Description |
|---|---|
| Account information | This refers to the person or group to which the CPU time is owed. It is set as per the rules of the company owning the mainframes. If it is specified as (*), then it takes the id of the user, who has currently logged into the Mainframe Terminal. |
| Programmer name | This identifies the person or group, who is in charge of the JCL. This is not a mandatory parameter and can be replaced by a comma. |
Keyword-param
Following are the various keyword parameters, which can be used in JOB statement. You can use one or more parameters based on requirements and they are separated by comma:| Keyword Parameter | Description |
|---|---|
| CLASS | Based on the time duration and the number of resources required
by the job, companies assign different job classes. These can be
visualized as individual schedulers used by the OS to receive the jobs.
Placing the jobs in the right scheduler will aid in easy execution of
the jobs. Some companies have different classes for jobs in test and
production environment. Valid values for CLASS parameter are A to Z characters and 0 to 9 numeric (of length 1). Following is the syntax: CLASS=0 to 9 | A to Z |
| PRTY | To specify the priority of the job within a job class. If this
parameter is not specified, then the job is added to the end of the
queue in the specified CLASS. Following is the syntax: PRTY=N Where N is a number in between 0 to 15 and higher the number, higher is the priority. |
| NOTIFY | The system sends the success or failure message (Maximum
Condition Code) to the user specified in this parameter. Following is
the syntax: NOTIFY="userid | &SYSUID" Here system sends the message to the user "userid" but if we use NOTIFY = &SYSUID, then the message is sent to the user submitting the JCL. |
| MSGCLASS | To specify the output destination for the system and Job messages when the job is complete. Following is the syntax: MSGCLASS=CLASS Valid values of CLASS can be from "A" to "Z" and "0" to "9". MSGCLASS = Y can be set as a class to send the job log to the JMR (JOBLOG Management and Retrieval: a repository within mainframes to store the job statistics). |
| MSGLEVEL | Specifies the type of messages to be written to the output destination specified in the MSGCLASS. Following is the syntax: MSGLEVEL=(ST, MSG) ST = Type of statements written to output log
|
| TYPRUN | Specifies a special processing for the job. Following is the syntax: TYPRUN = SCAN | HOLD Where SCAN and HOLD has the following description
|
| TIME | Specifies the time span to be used by the processor to execute the job. Following is the syntax: TIME=(mm, ss) or TIME=ss Where mm = minutes and ss = seconds This parameter can be useful while testing a newly coded program. In order to ensure that the program does not run for long because of looping errors, a time parameter can be coded so that the program abends when the specified CPU time is reached. |
| REGION | Specifies the address space required to run a job step within the job. Following is the syntax: REGION=nK | nM Here, region can be specified as nK or nM where n is a number, K is kilobyte and M is Megabyte. When REGION = 0K or 0M, largest address space is provided for execution.In critical applications, coding of 0K or 0M is prohibited to avoid wasting the address space. |
Example
//URMISAMP JOB (*),"tutpoint",CLASS=6,PRTY=10,NOTIFY=&SYSUID, // MSGCLASS=X,MSGLEVEL=(1,1),TYPRUN=SCAN, // TIME=(3,0),REGION=10KHere, JOB statement is getting extended beyond the 70th position in a line,so we continue in the next line which should start with "//" followed by one or more spaces.
Miscellaneous Parameters
There are few other parameters, which can be used with JOB Statement but they are not frequently used:| ADDRSPC | Type of storage used: Virtual or Real |
| BYTES | Size of data to be written to output log and the action to be taken when the size is exceeded. |
| LINES | Maximum number of lines to be printed to output log. |
| PAGES | Maximum number of pages to be printed to output log. |
| USER | User id used to submit the job |
| PASSWORD | Password of the user-id specified in the USER parameter. |
| COND and RESTART | These are used in conditional job step processing and are explained in detail while discussing conditional Processing. |
JCL - EXEC Statement
Each JCL can be made of many job steps. Each job step can execute a program directly or can call a procedure, which in turn executes one or more programs (job steps). The statement, which holds the job step program/procedure information is the EXEC statement.The purpose of the EXEC statement is to provide required information for the program/procedure executed in the job step. Parameters coded in this statement can pass data to the program in execution, can override certain parameters of JOB statement and can pass parameters to the procedure if the EXEC statement calls a procedure instead of directly executing a program.
Syntax
Following is the basic syntax of a JCL EXEC statement://Step-name EXEC Positional-param, Keyword-param
Description
Let us see the description of the terms used in above EXEC statement syntax.STEP-NAME
This identifies the job step within the JCL. It can be of length 1 to 8 with alphanumeric characters.EXEC
This is the keyword to identify it as an EXEC statement.POSITIONAL-PARAM
These are positional parameters, which can be of two types:| Positional Parameter | Description |
|---|---|
| PGM | This refers to the program name to be executed in the job step. |
| PROC | This refers to the procedure name to be executed in the job step. We will discuss it a separate chapter. |
KEYWORD-PARAM
Following are the various keyword parameters for EXEC statement. You can use one or more parameters based on requirements and they are separated by comma:| Keyword Parameter | Description |
|---|---|
| PARM | Used to provide parametrized data to the program that is being
executed in the job step. This is a program dependant field and do not
have definite rules, except that the PARM value has to be included
within quotation in the event of having special characters. For example given below, the value "CUST1000" is passed as an alphanumeric value to the program. If the program is in COBOL, the value passed through a PARM parameter in a JCL is received in the LINKAGE SECTION of the program. |
| ADDRSPC | This is used to specify whether the job step require virtual or
real storage for execution. Virtual storage is pageable whereas real
storage is not and is placed in the main memory for execution. Job
steps, which require faster execution can be placed in real storage.
Following is the syntax: ADDRSPC=VIRT | REAL When an ADDRSPC is not coded, VIRT is the default one. |
| ACCT | This specifies the accounting information of the job step. Following is the syntax: ACCT=(userid) This is similar to the positional parameter accounting information in the JOB statement. If it is coded both in JOB and EXEC statement, then the accounting information in JOB statement applies to all job steps where an ACCT parameter is not coded. The ACCT parameter in an EXEC statement will override the one present in the JOB statement for that job step only. |
Common Keyword Parameters of EXEC and JOB Statement
| Keyword Parameter | Description |
|---|---|
| ADDRSPC | ADDRSPC coded in JOB statement overrides the ADDRSPC coded in EXEC statement of any job step. |
| TIME | If TIME is coded in an EXEC statement, then it applies to that job step only. If it is specified in both JOB and EXEC statement, then both will be in effect and can cause time-out error due to either of it. It is not recommended to use TIME parameter in both the JOB and EXEC statement together. |
| REGION | If REGION is coded in an EXEC statement, then it applies to that job step only. REGION coded in JOB statement overrides the REGION coded in EXEC statement of any job step. |
| COND | Used to control the job step execution based on the return-code of the previous step. If a COND parameter is coded in an EXEC statement of a job step, then the COND parameter of the JOB statement (if present) is ignored. The various tests that can be performed using a COND parameter is explained in conditional Processing. |
Example
Following is a simple example of JCL script along with JOB and EXEC statements://TTYYSAMP JOB 'TUTO',CLASS=6,MSGCLASS=X,REGION=8K, // NOTIFY=&SYSUID //* //STEP010 EXEC PGM=MYCOBOL,PARAM=CUST1000, // ACCT=(XXXX),REGION=8K,ADDRSPC=REAL,TIME=1440
JCL - DD Statement
Datasets are mainframe files with records organised in a specific format. Datasets are stored on the Direct Access Storage Device (DASD) or Tapes of the mainframe and are basic data storage areas. If these data are required to be used/created in a batch program, then the file (i.e., dataset) physical name along with the file format and organisation are coded in a JCL.The definition of each dataset used in the JCL is given using the DD statement. The input and output resources required by a job step needs to be described within a DD statement with information such as the dataset organisation, storage requirements and record length.
Syntax
Following is the basic syntax of a JCL DD statement://DD-name DD Parameters
Description
Let us see the description of the terms used in above DD statement syntax.DD-NAME
A DD-NAME identifies the dataset or input/output resource. If this is an input/output file used by a COBOL/Assembler program, then the file is referenced by this name within the program.DD
This is the keyword to identify it as an DD statement.PARAMETERS
Following are the various parameters for DD statement. You can use one or more parameters based on requirements and they are separated by comma:| Parameter | Description |
|---|---|
| DSN | The DSN parameter refers to the physical dataset name of a newly
created or existing dataset. The DSN value can be made up of sub-names
each of 1 to 8 characters length, separated by periods and of total
length of 44 characters (alphanumeric). Following is the syntax: DSN=Physical Dataset Name Temporary datasets need storage only for the job duration and are deleted at job completion. Such datasets are represented as DSN=&name or simply without a DSN specified. If a temporary dataset created by a job step is to be used in the next job step, then it is referenced as DSN=*.stepname.ddname. This is called Backward Referencing. |
| DISP | The DISP parameter is used to describe the status of the
dataset, disposition at the end of the job step on normal and abnormal
completion. DISP is not required in a DD statement only when the dataset
gets created and deleted in the same job step (like the temporary
datasets). Following is the syntax: DISP=(status, normal-disposition, abnormal-disposition) Following are valid values for status:
|
| DCB | The Data Control Block (DCB) parameter details the physical
characteristics of a dataset. This parameter is required for datasets
that are newly created in the job step. LRECL is the length of each record held within the dataset. RECFM is the record format of the dataset. RECFM can hold values FB, V or VB. FB is a fixed block organisation where one or more logical records are grouped within a single block. V is variable organisation where one variable length logical record is placed within one physical block. VB is Variable Block organisation where one or more variable length logical records are placed within one physical block. BLKSIZE is the size of the physical block. The larger the block, greater is the number of records for a FB or VB file. DSORG is the type of dataset organisation. DSORG can hold values PS (Physical Sequential), PO (Partitioned Organisation) and DA (Direct Organisation). When there is a need to replicate the DCB values of one dataset to another within the same jobstep or JCL, then it is specified as DCB=*.stepname.ddname where stepname is the name of the job step and ddname is the dataset from which the DCB is copied. Check below example where RECFM=FB,LRECL=80 forms the DCB of dataset OUTPUT1. |
| SPACE | The SPACE parameter specifies the space required for the dataset
in the DASD (Direct Access Storage Disk). Following is the syntax: SPACE=(spcunits, (pri, sec, dir), RLSE) Here is the description of all the used parameters:
|
| UNIT | The UNIT and VOL parameters are listed in the system catalog for
catalogued datasets and hence can be accessed with just the physical DSN
name. But for uncataloged datasets, the DD statement should include
these parameters. For new datasets to be created, the UNIT/VOL
parameters can be specified or the Z/OS allocates the suitable device
and volume. The UNIT parameter specifies the type of device on which the dataset is stored. The device type can be identified using Hardware Address or Device type group. Following is the syntax: UNIT=DASD | SYSDA Where DASD stands for Direct Access Storage Device and SYSDA stands for System Direct Access and refers to the next available disk storage device. |
| VOL | The VOL parameter specifies the volume number on the device identified by the UNIT parameter. Following is the syntax: VOL=SER=(v1,v2) Where v1, v2 are volume serial numbers. You can use the following syntax as well: VOL=REF=*.DDNAME Where REF is the backward reference to the volume serial number of a dataset in any of the preceding job steps in the JCL. |
| SYSOUT | The DD statement parameters discussed so far corresponds to data
being stored in a dataset. The SYSOUT parameter directs the data to
output device based on the class specified. Following is the syntax SYSOUT=class Where if class is A then it directs output to printer, and if class is * then it directs output to same destination as that of the MSGCLASS parameter in the JOB statement. |
Example
Following is an example, which makes use of DD statements along with various parameters explained above://TTYYSAMP JOB 'TUTO',CLASS=6,MSGCLASS=X,REGION=8K, // NOTIFY=&SYSUID //* //STEP010 EXEC PGM=ICETOOL,ADDRSPC=REAL //* //INPUT1 DD DSN=TUTO.SORT.INPUT1,DISP=SHR //INPUT2 DD DSN=TUTO.SORT.INPUT2,DISP=SHR,UNIT=SYSDA, // VOL=SER=(1243,1244) //OUTPUT1 DD DSN=MYFILES.SAMPLE.OUTPUT1,DISP=(,CATLG,DELETE), // RECFM=FB,LRECL=80,SPACE=(CYL,(10,20)) //OUTPUT2 DD SYSOUT=*
JCL - Base Library
Base Library is the Partitioned Dataset (PDS), which holds the load modules of the program to be executed in the JCL or the catalogued procedure, which is called in the program. Base libraries can be specified for the whole JCL in a JOBLIB library or for a particular job step in a STEPLIB statement.JOBLIB Statement
A JOBLIB statement is used in order to identify the location of the program to be executed in a JCL. The JOBLIB statement is specified after the JOB statement and before the EXEC statement. This can be used only for the in stream procedures and programs.Syntax
Following is the basic syntax of a JCL JOBLIB statement://JOBLIB DD DSN=dsnname,DISP=SHR
The JOBLIB statement is applicable to all the EXEC statements within
the JCL. The program specified in the EXEC statement will be searched in
the JOBLIB library followed by the system library.For example, if the EXEC statement is executing a COBOL program, the load module of the COBOL program should be placed within the JOBLIB library.
STEPLIB Statement
A STEPLIB statement is used in order to identify the location of the program to be executed within a Job Step. The STEPLIB statement is specified after the EXEC statement and before the DD statement of the job step.Syntax
Following is the basic syntax of a JCL STEPLIB statement://STEPLIB DD DSN=dsnname,DISP=SHR
The program specified in the EXEC statement will be searched in the
STEPLIB library followed by the system library. STEPLIB coded in a job
step overrides the JOBLIB statement.Example
The following example shows the usage of JOBLIB and STEPLIB statements://MYJCL JOB ,,CLASS=6,NOTIFY=&SYSUID //* //JOBLIB DD DSN=MYPROC.BASE.LIB1,DISP=SHR //* //STEP1 EXEC PGM=MYPROG1 //INPUT1 DD DSN=MYFILE.SAMPLE.INPUT1,DISP=SHR //OUTPUT1 DD DSN=MYFILES.SAMPLE.OUTPUT1,DISP=(,CATLG,DELETE), // RECFM=FB,LRECL=80 //* //STEP2 EXEC PGM=MYPROG2 //STEPLIB DD DSN=MYPROC.BASE.LIB2,DISP=SHR //INPUT2 DD DSN=MYFILE.SAMPLE.INPUT2,DISP=SHR //OUTPUT2 DD DSN=MYFILES.SAMPLE.OUTPUT2,DISP=(,CATLG,DELETE), // RECFM=FB,LRECL=80Here, the load module of the program MYPROG1 (in STEP1) is searched in the MYPROC.SAMPLE.LIB1. If not found, it is searched in the system library. In STEP2, STEPLIB overrides JOBLIB and load module of the program MYPROG2 is searched in MYPROC.SAMPLE.LIB2 and then in the system library.
INCLUDE Statement
A set of JCL statements coded within a member of a PDS can be included to a JCL using an INCLUDE statement. When the JES interprets the JCL, the set of JCL statements within the INCLUDE member replaces the INCLUDE statement.Syntax
Following is the basic syntax of a JCL INCLUDE statement://name INCLUDE MEMBER=member-nameThe main purpose of INCLUDE statement is reusability. For example, common files to be used across many JCLs can be coded as DD statements within INCLUDE member and used in a JCL.
Dummy DD statements, data card specifications, PROCs, JOB, PROC statements cannot be coded within an INCLUDE member. An INLCUDE statement can be coded within an INCLUDE member and further nesting can be done up to 15 levels.
JCLLIB Statement
A JCLLIB statement is used to identify the private libraries used in the job. It can be used both with instream and cataloged procedures.Syntax
Following is the basic syntax of a JCL JCLLIB statement://name JCLLIB ORDER=(library1, library2....)The libraries specified in the JCLLIB statement will be searched in the given order to locate the programs, procedures and INCLUDE member used in the job. There can be only one JCLLIB statement in a JCL; specified after a JOB statement and before EXEC and INCLUDE statement but it cannot be coded within an INCLUDE member.
Example
In the following example, the program MYPROG3 and INCLUDE member MYINCL is searched in the order of MYPROC.BASE.LIB1, MYPROC.BASE.LIB2, system library.//MYJCL JOB ,,CLASS=6,NOTIFY=&SYSUID //* //MYLIB JCLLIB ORDER=(MYPROC.BASE.LIB1,MYPROC.BASE.LIB2) //* //STEP1 EXEC PGM=MYPROG3 //INC INCLUDE MEMBER=MYINCL //OUTPUT1 DD DSN=MYFILES.SAMPLE.OUTPUT1,DISP=(,CATLG,DELETE), // RECFM=FB,LRECL=80 //*
JCL - Procedures
The JCL Procedures are set of statements inside a JCL grouped together to perform a particular function. Usually, the fixed part of the JCL is coded in a procedure. The varying part of the Job is coded within the JCL.You can use a procedure to achieve parallel execution of a program using multiple input files. A JCL can be created for each input file, and a single procedure can be called simultaneously by passing the input file name as a symbolic parameter.
Syntax
Following is the basic syntax of a JCL procedure definition://* //Step-name EXEC procedure nameThe contents of the procedure are held within the JCL for an instream procedure. The contents are held within a different member of the base library for a cataloged procedure. This chapter is going to explain two types of procedures available in JCL and then finally we will see how we can nest various procedures.
Instream Procedure
When the procedure is coded within the same JCL member, it is called an Instream Procedure. It should start with a PROC statement and end with a PEND statement.//SAMPINST JOB 1,CLASS=6,MSGCLASS=Y,NOTIFY=&SYSUID //* //INSTPROC PROC //*START OF PROCEDURE //PROC1 EXEC PGM=SORT //SORTIN DD DSN=&DSNAME,DISP=SHR //SORTOUT DD SYSOUT=*MYINCL //SYSOUT DD SYSOUT=* //SYSIN DD DSN=&DATAC LRECL=80 // PEND //*END OF PROCEDURE //* //STEP1 EXEC INSTPROC,DSNME=MYDATA.URMI.INPUT1, // DATAC=MYDATA.BASE.LIB1(DATA1) //* //STEP2 EXEC INSTPROC,DSNME=MYDATA.URMI.INPUT2 // DATAC=MYDATA.BASE.LIB1(DATA1) //*In the above example, the procedure INSTPROC is called in STEP1 and STEP2 using different input files. The parameters DSNAME and DATAC can be coded with different values while calling the procedure and these are called as symbolic parameters. The varying input to the JCL such as file names, datacards, PARM values, etc., are passed as symbolic parameters to procedures.
While coding symbolic parameters, do not use KEYWORDS, PARAMETERS or SUB-PARAMETERS as symbolic names. Example: Do not use TIME=&TIME but yes you can use TIME=&TM and it is assumed as a right way of coding symbolics.
User-defined symbolic parameters are called JCL Symbols. There are certain symbols called system symbols, which are used for logon job executions. The only system symbol used in batch jobs by normal users is &SYSUID and this is used in the NOTIFY parameter in the JOB statement.
Cataloged Procedure
When the procedure is separated out from the JCL and coded in a different data store, it is called a Cataloged Procedure. A PROC statement is not mandatory to be coded in a cataloged procedure. Following is an example of JCL where it's calling CATLPROC procedure://SAMPINST JOB 1,CLASS=6,MSGCLASS=Y,NOTIFY=&SYSUID //* //STEP EXEC CATLPROC,PROG=CATPRC1,DSNME=MYDATA.URMI.INPUT // DATAC=MYDATA.BASE.LIB1(DATA1)Here, the procedure CATLPROC is cataloged in MYCOBOL.BASE.LIB1. PROG,DATAC and DSNAME are passed as symbolic parameters to the procedure CATLPROC.
//CATLPROC PROC PROG=,BASELB=MYCOBOL.BASE.LIB1 //* //PROC1 EXEC PGM=&PROG //STEPLIB DD DSN=&BASELB,DISP=SHR //IN1 DD DSN=&DSNAME,DISP=SHR //OUT1 DD SYSOUT=* //SYSOUT DD SYSOUT=* //SYSIN DD DSN=&DATAC //*
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