Baseline Jcl Day1

8/4/2019 Baseline Jcl Day1

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JCL

DAY 1


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J C L

JOB CONTROL LANGUAGE


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Determinethejob

CreatetheJCL

SubmittheJOB

JESinterpretsJCL andpasses it

to

MVS

MVS does

the work

UserViews andInterprets

output

JEScollects

the outputand information

aboutthe JOB

SystemMessages


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WHY JCL ???

MVS operating system is designed to work

in the batch processing mode

JCL is a powerful and flexible language

that helps to customize the use of localand remote resources available to one or

more computers


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Difference between batch &

interactive processingBatch processing

Jobs submitted are

executed at later time User can not interact Performance measure is

throughput

Snapshot of output isused for debugging

Interactive processing

Jobs submitted are

executed immediately User can interact Performance measure is

response time

Interactive debugging


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Various stages of JCL execution

Input Conversion

Execution Output Hard copy Purge

f


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Input JES gives a unique jobnumber

Conversion Check syntax error & Place itin JES spool

Initiator Taking the job from the spooland sending it for execution

Output sends the output to printer

Purge After job is processed,it ispurged

Various stages of JCLexecution


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Stages of Job Processing - INPUT

Job entry or input is how jobs are entered

into the system.

Local and remote card readers

Via a started procedure

Internal readerFrom another system via network job entry

Several methods are :


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Stages of Job Processing - INPUT

INPUT

SPOOL

JCL

SYSINJES

MVS

During input processing , the job is placed out on spool.At this point in time, a job consists of :

Any JOB Control Language

Any JOB Entry Control Language (JECL) in the Input StreamAny data SYSIN in the Input Stream

An entry is initialized in the Jobqueue and the job is assigned a

JES Job Number as part of Input Processing


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Stages of Job Processing -CONVERSIONSPOOL

JCL

SYSIN

During conversion the JCL for a job is converted to its internal

form, known as Converter/Interpreter text. All of the jobs that

were marked awaiting conversion in the job Queue are converted

MVS

JES

PROCLIB

PROC

Full Syntax checking of the JCL is done at this time

Input to the conversion process consists of the Original JCL and

any cataloged procedure referenced by it


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Stages of Job Processing -CONVERSION

JOB INTERPRETER - JES2

JES2

ADDRESS

SPACE

INITIATOR

ADDRESS

SPACE

PAY

JCLINTERPRETER

PAY

CONTROL

BLOCKS

JES2 gives job to idle initiator

Initiator attaches the interpreter

to build control blocks

Control blocks used to start job

in initiator


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Stages of Job Processing -CONVERSION

JOB INTERPRETER - JES3

JES3

ADDRESS

SPACE

INITIATOR

ADDRESS

SPACE

PAY

JCL

INTERPRETER

PAY

CONTROL

BLOCKS

JES3 Attaches the interpreter

Interpreter builds the control

blocks in the JES3 address space

JES3 passes the CONTROL

blocks to an idle initiator to

start execution.


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Stages of Job Processing - EXECUTION

JES selects a job for execution , based upon job CLASS

and job selection PRTYex. //PAY JOB PRTY=8,CLASS=A

Allocation ( of data sets and devices necessary for execution )

is performed.

If the program reads any SYSIN data, a copy will be read

from Spool and presented to the program.

If the program creates any SYSOUT data, it will be

Spooled, rather than sent directly to an output device.


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Stages of Job Processing - OUTPUT

After the job has terminated, the output created isanalysed and grouped according to SYSOUTclass and output characteristics

Entries are then created in the Job Output Table(JOT) to reflect these various groupings


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Stages of Job Processing - HARDCOPY

During this phase, job output characteristics andthe output is sent to the physical devices.


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Stages of Job Processing - PURGE

During Purge processing, all of the resources allocatedto the job in earlier phases can be freed for re-use.These include :

Spool Space

Jobqueue space

JES job number


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JCL PROCESSING

JCL

SYSIN

SYSOUT

SPOOLJES2 /

JES3

JES2 /

JES3

INITIATOR1 INITIATOR2PRINTER

INPUT

STREAM


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JCL execution

JCL INITIATION

STEP INITIATION

ALLOCATION

PROGRAM EXECUTION

STEP TERMINATION

JOB TERMINATION

JCL

SYSIN

SYSOUT


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QUESTIONS ???

JCL is used to write an application program ?

Yes/No

What are the different stages of JCL processing ?


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JCL statements

JOB Job identification

EXEC Instruction for execution

DD Source of data to operate


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TYPE OF STATEMENTS

JOB CONTROL STATEMENTS

UTILITY CONTROL STATEMENTS


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Basic Format of a JCL :

JCL statements are coded in 80 byterecords -

Only 72 of the 80 chars available to codeJCL -

last eight columns of each record reserved foran optional sequence number


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JCL STATEMENT FORMAT

//P123 JOB 1234,AMLAN,CLASS=E

Name Parameters

Operation

Identifier Comment


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Basic Format of a JCL : ...

Identifier [Name] [Operation][Parameters] [Comments]

Identifier Two slashes ( // ) starting in col 1.

Exceptions -

1) For a delimiter statement, /* starting in col 1

2) For a comment statement , //* starting at col1

Name One to eight alphanumeric , starting with a

letter char. Must begin at col 3.


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Basic Format of a JCL : ...

OperationA valid operation code, such as JOB, EXEC or

DD. Must be preceded and followed by a space.

Parameters

One or more parameters depending on theoperation. Individual parameters are separatedfrom one another by commas, no interveningspaces.

Comments

comments may follow parameters, preceded byone space and not extending beyond col 71


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JCL parameters :

JCL parameters : 1) Positional parameters - Must occur at a specific position within the

parameters field

account for a missing parameter by a comma

2) Keyword parameters -

UNIT=SYSDA ( no spaces ) UNIT is a keyword parameter of value SYSDA

Keyword parameters to come only after allpositional parameters have been coded, order ofkeyword parameters immaterial


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JCL subparameters :

DCB=(DSORG=PO,LRECL=80,BLKSIZE=6160)

DCB=(DSORG=PO)DCB=DSORG=PO

DISP=(,DELETE)

Comma place holders are required only for missingpositional subparameters.


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Continuing JCL statements: ... Break the parameter field with the comma

that follows a parameter or sub-parameter

Slashes in column 1 & 2 of following line Next parameter or sub parameter starting

anywhere between columns 4 - 16

//SYSUT2 DD DSNAME=...,DISP=...,// UNIT=SYSDA,VOL=SER=MPS800,

// SPACE=(CYL,(10,5,2)),// DCB=DSORG=PO

( X ) Avoid continuing comments from line to line.

G id li


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Guidelines :

JCL cryptic :

Code just one or two parameters per line

align the operation and parameters fields

of each statement

begin job with a group of commentstatements that document a job thoroughly

Name, date of coding, what each job stepdoes, any special processing requirements

Dont forget to update comments !


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JCL statements

JOB Job identification

EXEC Instruction for execution

DD Source of data to operate


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JOB STATEMENT

ACCT CLASS

NAME NOTIFY

MSGLEVEL TYPRUNMSGCLASS PRTY

COND RESTART

USER REGION

PASSWORD PERFORM

TIME


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IMPORTANT JOB PARAMETERS

positional parameters

( a/c inf ),name

ex. //TCSABCDA JOB (A123),AMLAN

All these parameters are optional as far as JCL is concerned,

they are probably required by your installation.


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keyword parameters

( CLASS )

ex. //TCSABCDA JOB CLASS=A

CLASS specifies the job class that is the nature of the job.

Installation will specify which of the 36 possible classes to use

which is from A to Z and 0 to 9 .

Installation establishes a default class that is in effect if CLASS

is omitted.


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keyword parameters

( MSGCLASS )

ex. //TCSABCDA JOB MSGCLASS=A

MSGCLASS specifies the job scheduler message output class.

Job scheduler messages include all messages not printed by the

job steps being executed but the JCL messages and system messages

Installation establishes a default class that is in effect if CLASS

is omitted.


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keyword parameters

( MSGLEVEL )

ex. //TCSABCDA JOB MSGLEVEL=(1,1)

MSGLEVEL(jcl,allocations) specifies the printing of JCLstatements and allocation messages.

ex. MSGLEVEL(0,1) will print only JOB statement, and

all the allocation,JES,SMS and operator messages

By default it is MSGLEVEL(1,1)


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keyword parameters

( NOTIFY )

ex. //TCSABCDA JOB NOTIFY=TCS

NOTIFY notifies you at a time-sharing terminal when the job is

completed.



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keyword parameters

( TYPRUN )

ex. //TCSABCDA JOB TYPRUN=SCAN

TYPRUN checks the JCL and holds the job in the input queue.

TYPRUN = SCAN checks the JCL for syntax errors and suppresses execution

of the job

TYPRUN = HOLD holds the JCL in the input queue for later execution.It is helduntil the operator releases it.

TYPRUN = JCLHOLD(JES2 only) similar to HOLD but the difference is it is

checked while it is not with the HOLD option.

TYPRUN = COPY(JES2 only) lists or duplicates the lines placed in the JOBstatement to the class assigned in the MSGCLASS parameter and suppressesexecution.

SOME OTHER keyword JOB PARAMETERS


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PRTY=priority : is related to the CLASS parameter. It assignspriority to jobs which belong to the same class.priority numbers

range from (0-14) or (0-15) depending on installations.

TIME=(min,sec) : signifies how much time the JOB must take to

run.

RESTART=STEP3 :Forces the JOB execution to start from STEP3.



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REGION=96K :To override the default amount of workspace

assigned for the job.

COND=(4,LT) :Permits the execution of a steps to depend on the

return code from the previous steps.Will be dealt in detail in Day2.

ADDRSPC=REAL : It is used to specify whether the program is

to use REAL or VIRTual ADDRess SPaCe. Default is Virtual. If

Real is coded then the REGION parameter is also to be coded.


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Various stages of JOBProcessing

Input Conversion

Execution Output Hard copy Purge


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JOB ENTRY SUBSYSTEM

JES2 / JES3

JES2 or JES3 statements can be includedto communicate with JES concerning...

INPUT

OUTPUT PROCESSING


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JES2 Control Statements

$COMMAND OUTPUT SIGNOFF

JOBPARAM PRIORITY SIGNON

MESSAGE ROUTE XEQ

NETACCT SETUP XMIT

NOTIFY


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JES2 Control Statements

NOTIFY - direct jobs notification messages to a user.

PRIORITY or PRTY -Assign a selection priority for yourjob. Within a job class, a job with a higher priority is

selected for execution sooner.

JES2 Control statements are precededwith /* in col1 & col2.


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Errors

JCL syntax errors.

JOB will not be submitted

JCL allocation errors.

JES2-subsequent steps will not get executed.JES3-detects errors in the beginning.


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Abend Failures

An ABEND failure occurs under the following

conditions:

A program while executing, attempts to perform an

instruction or operation which the system recognizes

as being impossible or unacceptable.

Causes of Abend


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Causes of Abend

FailuresLogic error

JCL error

Resource unavailabilityExceeding limits (Time or Space on DASD)

Hardware Malfunction

User ABENDSOperator intervention

Operating System failure


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Thats all for

DAY

1

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Baseline Jcl Day1

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