jcl & jes basics

8/3/2019 Jcl & Jes Basics

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Introduction To JCL

JCL - JOB CONTROL LANGUAGE

JCL is a language that directs the operating system in the handling of application programs. It is a means of communication between an

application program and the operating system of the computer.

z/OS uses a job entry subsystem or JES to receive jobs into the system,schedule them for processing, and control their output processing.

Provides specifications necessary to process a job.

Job is a collection of JCL statements that executes one or morerelated programs.


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Purpose of JCL

JCL does the following:

Directs the operating system on what is to be done in terms

of running applications and scheduling resources.

A means for telling operating system:Who you are (allows priority distinctions)Space and time requirementsThe programs to executeThe Input/output data sets are needed by programs


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Jobstream, Jobs, and Job Steps

JOBSTREAM:A set of JOBS that are run by the computer one after another .

JOB:A set of one or more tasks that are run in sequence.

JOB STEP:Each program executed by a JOB.


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What is JES?

A Job Entry Subsystem Manages I/O Job Queues and Data:

Receiving Jobs Into The O/S

Schedule for ProcessingControlling Output Processing

Versions Of JES:JES2 and JES3


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General JCL Rules

Must begin with // (except for the /* statement) in columns 1and 2.Is case-sensitive (lower-case is just not permitted).

NAME field is optional.Must begin in column 3 if used.Must code one or more blanks if omitted.OPERATION field must begin on or before column 16.

OPERATION field stands alone.OPERANDS must end before column 72.OPERANDS are separated by commas.All fields, except for the operands, must be separated by oneblank.


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Basic JCL Statements

The three basic JCL statements are:JOBEXEC

DD


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Structure of JCL Statements

Each JCL statement is divided into several fields like[Identifier], [Name], [Operation], [Parameters], and[Comments].

Identifier Field:Identifies a record as a JCL statement.Occupies first two character positions:

// -: Usual JCL statement//* -: Comment statement/* -: Delimiter statement


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Nam e Field:Must begin in column three.Consists of one to eight characters, which may be letters,

numbers or national characters (#,@, and $).

Operation Field:The three different operation fields are:

JOBEXECDD


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Pa r am eters Field:

Begins at least one position after the end of the operation

field and can extend up to column 71.

Individual parameters are separated by commas.

Two types of parameters are:Po siti o na l: Must occ ur in spe cifi c positi o n.Keyw o rd : M a y no t be in spe cifi c po siti on.


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Format of a JCL statement


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JOB Statement Parameters

CLASS : Tells to OS about the nature of job:CLASS=jobclass [Here jobclass:A-Z,0-9]

MSGCLASS : Determines the output device to which written.MSGCLASS=class [Here class:A-Z,0-9]

NOT IFY:Specifies the userid to which the message has to be

sent upon Job completion.NOTIFY = userid


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EXEC Statement Syntax


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EXEC Statement Parameters

PG M: S pe cify the Pr og r am t o be exe cuted:PGM=program-name

PRO C : S pe cify the ca t a l og ued o r In-stre am Pr oc edure t o exe cute:

PROC=Procedure-nameP A RM: S pe cify the input p a r am eters t o the pr og r am :

PARM=(parm1,parm2, )


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EXEC Statement Examples

An EXEC that executes program PAY5B10 in step PAYLIST://PAYLIST EXEC PGM=PAY5B10

An EXEC that passes a parameter value of LINECT=0050 toprogram IEBDG:

//DATAGEN EXEC PGM=IEBDG,PARM='LINECT=0050

An EXEC statement passing three parameters to programHEWL:

//LINKED EXEC PGM=HEWL,PARM='LET,MAP,XREF'


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DD Statement Syntax


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DD Statement Parameters

D S N A ME: Nam es the d a t a set:{DSNAME}=dataset-name{DSN}={data-set-name(member)}

U N IT : Requests a ll oc a ti on t o a spe cifi c devi ce, a type o r a g r oup o f devi ces:

UNIT=device-name/device-type/device-number

V O LU ME/ V O L: Identifies the v o lum es o n whi ch the d a t a set resides o r will reside:

VOL=SER=serial-number


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SPACE: Requests space for a new dataset on the DASD:

SPACE=({TRK, } (primary-qty [,second-qty] [,directory])[,RLSE] [,CONTIG] [,ROUND] ){CYL, } [, ] [,index ]

[, ] [,MXIG ]{blklgth,} [,ALX ]{reclgth,} [, ]DCB: Completes information in Data Control Block:

DCB=(option1,option2..)


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D ISP: T his is the disp ositi o n p a r am eter th a t spe cifies wh a t a cti o n needs t o be t ak en o n a d a t a set o n d a t a set on n o r ma l a nd a bn o r ma l ter m ina ti o n.

DISP =(Status,Normal,Abnormal)

S t a tus: T he st a tus o f a d a t a set a t the be g innin g o f j o bNEW,OLD,SHR,MOD

N o r ma l: S pe cifies wh a t t o d o with the d a t a set if the pr og r am ter m ina tes n o r ma lly:

KEEP,PASS,DELETE,CATLGA bn o r ma l: S pe cifies wh a t t o d o with the d a t a set if the

pr og r am ter m ina tes a bn o r ma lly:KEEP,DELETE


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DD Statement Example

A DD statement that allocates an existing data set://INVMAST DD DSNAME=MM01.INVNTORY.MASTER,DISP=SHR

A DD statement that allocates a new data set://INVMAST DD DSNAME=MM01.ACCOUNT.MASTER,DISP=(NEW,CATLG),

// UNIT=SYSDA,VOL=SER=MPS8BV,// SPACE=(CYL,(10,2)),// DCB=(DSORG=PS,RECFM=FB,LRECL=100)


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JCL Basics Info

A JCL member consists of a file of 80-byte, fixed-lengthrecords.The JCL statements are written in positions 1-71.Position 72 is reserved for continuation, a non-space

character indicates the next statement, which will be acontinuation of the current statement.A JCL statement begins with two slashes in positions 1 and 2.Every JCL member must begin with a '"Job Card" that specifies

the job name and other information about how the job willexecute.Each step executes a program or procedure (PROC).The JCL is completed by using '//' in positions 1 and 2 or, when

the last statement is processed.

jcl & jes basics

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