Job Control Language Bhargava KC Extension 52067 E R

Job Control Language Bhargava KC Extension: 52067 E&R Rotunda, II Floor, Cubicle 15 Email: bhargava_sastry@infy. com 3/19/2018 3 ER/CORP/CRS/OS 02/003 -1

JOB CONTROL LANGUAGE For IBM Mainframe System 390 3/19/2018 4 ER/CORP/CRS/OS 02/003 -1

Pre-requisites § Programming Fundamentals. § MVS Operating system and its subsystem TSO. § Navigating through ISPF. 3/19/2018 5 ER/CORP/CRS/OS 02/003 -1

Evaluation Scheme § Quiz : 20 Marks ( Conducted after 2 sessions of Input ) § OLE : 80 Marks 3/19/2018 6 ER/CORP/CRS/OS 02/003 -1

References # Title Authors Publishers 1. MVS JCL Doug Lowe Mike Murarch and Associates 2. System 370/390 JCL GD Brown 3. IBM Manuals 3/19/2018 7 ER/CORP/CRS/OS 02/003 -1

Objectives of the Course 1. To acquaint participants to the specific nature of Job Control Language. 2. To illustrate the syntax of JCL. 3. To demonstrate the JCL programs, procedures, Various Data set allocation mechanisms, IBM Utilities 4. To acquaint the participants regarding the importance of VSAM, GDGs, and concepts of SMS. 3/19/2018 8 ER/CORP/CRS/OS 02/003 -1

Objectives of the Session 1. To learn about JES as a Sub system and its functions. 2. About JCL syntax in general 3. About Job statement. 4. Some sample examples. 3/19/2018 9 ER/CORP/CRS/OS 02/003 -1

JOB AND A JCL A JOB is the execution of one or more related programs in sequence. Each Program to be executed by a Job is Called a Step. Ex: The first program sorts customer names in a sequence The second program generates a report. Job Control Language is a set of control statements that Provides specifications necessary to process a Job. ER/CORP/CRS/OS 02/003 -1 3/19/2018 10

J JOB C CONTROL ER/CORP/CRS/OS 02/003 -1 L LANGUAGE 3/19/2018 11

Determine the job Create the JCL JES interprets JCL and passes it to MVS Submit the JOB System Messages User Views and Interprets output ER/CORP/CRS/OS 02/003 -1 MVS does the work JES collects the output and information about the JOB 3/19/2018 12

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 local and remote resources available to one or more computers ER/CORP/CRS/OS 02/003 -1 3/19/2018 13

Difference between batch & interactive processing Batch processing • Jobs submitted are executed at later time • User can not interact • Performance measure is throughput • Snapshot of output is used for debugging Interactive processing • Jobs submitted are executed immediately • User can interact • Performance measure is response time • Interactive debugging ER/CORP/CRS/OS 02/003 -1 3/19/2018 14

Various stages of JCL execution • • • Input Conversion Execution Output Hard copy Purge ER/CORP/CRS/OS 02/003 -1 3/19/2018 15

Various stages of JCL execution • Input • Conversion • Initiator • Output • Purge JES gives a unique job number Check syntax error & Place it in JES spool Taking the job from the spool and sending it for execution sends the output to printer After job is processed, it is purged ER/CORP/CRS/OS 02/003 -1 3/19/2018 16

• Stages of Job Processing - INPUT Job entry or input is how jobs are entered into the system. Several methods are : • Local and remote card readers • Via a started procedure • Internal reader • From another system via network job entry ER/CORP/CRS/OS 02/003 -1 3/19/2018 17

Stages of Job Processing - INPUT MVS INPUT SPOOL JES JCL SYSIN 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 Stream • Any data SYSIN in the Input Stream An entry is initialized in the Jobqueue and the job is assigned a 3/19/2018 JES Job Number as part of Input Processing 18 ER/CORP/CRS/OS 02/003 -1

Stages of Job Processing -CONVERSION MVS JES SPOOL JCL SYSIN PROCLIB PROC • Input to the conversion process consists of the Original JCL and any cataloged procedure referenced by it • Full Syntax checking of the JCL is done at this time • 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 ER/CORP/CRS/OS 02/003 -1 3/19/2018 19

Stages of Job Processing -CONVERSION JOB INTERPRETER - JES 2 PAY JCL INTERPRETER • JES 2 gives job to idle initiator • Initiator attaches the interpreter to build control blocks PAY CONTROL BLOCKS JES 2 ADDRESS SPACE • Control blocks used to start job in initiator INITIATOR ADDRESS SPACE ER/CORP/CRS/OS 02/003 -1 3/19/2018 20

Stages of Job Processing -CONVERSION JOB INTERPRETER - JES 3 • JES PAY JCL • Interpreter builds the control blocks in the JES address space INTERPRETER PAY CONTROL BLOCKS JES 3 ADDRESS SPACE Attaches the interpreter INITIATOR ADDRESS SPACE • JES passes the CONTROL blocks to an idle initiator to start execution. ER/CORP/CRS/OS 02/003 -1 3/19/2018 21

Stages of Job Processing - EXECUTION 1. Initiator Invokes a program called Interpreter which goes thru the Job Input and creates a series of Control blocks in Scheduler Work Area , a part of Address space Private Area. 2. It then invokes Allocation routines that decides on what resources the Job step needs in terms of Units , Volumes and Data sets. 3. Initiator then builds a User region where the User’s program is loaded , control is transferred to Program and the program gets executed. 4. When the Program execution is over Initiator invokes deallocation routines to release all the resources that are used. ER/CORP/CRS/OS 02/003 -1 3/19/2018 22

Stages of Job Processing - EXECUTION • INITIATOR is responsible for the EXECUTION step of the Job Initiator Eligible Job classes 1 A 2 B, C, D, H, L, T 3 B, C, D, H, L, T 4 B, C 5 B, C 6 C ER/CORP/CRS/OS 02/003 -1 3/19/2018 23

Stages of Job Processing - EXECUTION • JES selects a job for execution , based upon job CLASS and job selection PRTY ex. //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. ER/CORP/CRS/OS 02/003 -1 3/19/2018 24

Stages of Job Processing - OUTPUT • • After the job has terminated, the output created is analysed and grouped according to SYSOUT class and output characteristics Entries are then created in the Job Output Table (JOT) to reflect these various groupings ER/CORP/CRS/OS 02/003 -1 3/19/2018 25

Stages of Job Processing - HARDCOPY • During this phase, job output characteristics and the output is sent to the physical devices. ER/CORP/CRS/OS 02/003 -1 3/19/2018 26

Stages of Job Processing - PURGE • During Purge processing, all of the resources allocated to the job in earlier phases can be freed for re-use. These include : – Spool Space – Jobqueue space – JES job number ER/CORP/CRS/OS 02/003 -1 3/19/2018 27

JCL PROCESSING INPUT STREAM JES 2 / JES 3 SPOOL JCL SYSIN SYSOUT PRINTER JES 2 / JES 3 INITIATOR 1 ER/CORP/CRS/OS 02/003 -1 INITIATOR 2 3/19/2018 28

JCL execution JCL INITIATION STEP INITIATION JCL SYSIN SYSOUT ALLOCATION PROGRAM EXECUTION STEP TERMINATION ER/CORP/CRS/OS 02/003 -1 JOB TERMINATION 3/19/2018 29

QUESTIONS ? ? ? • JCL is used to write an application program ? Yes/No • What are the different stages of JCL processing ? ER/CORP/CRS/OS 02/003 -1 3/19/2018 30

JCL statements JOB Job identification EXEC Instruction for execution DD Source of data to operate ER/CORP/CRS/OS 02/003 -1 3/19/2018 31

TYPE OF STATEMENTS • JOB CONTROL STATEMENTS • UTILITY CONTROL STATEMENTS ER/CORP/CRS/OS 02/003 -1 3/19/2018 32

Basic Format of a JCL : • JCL statements are coded in 80 byte records – Only 72 of the 80 chars available to code JCL • last eight columns of each record reserved for an optional sequence number ER/CORP/CRS/OS 02/003 -1 3/19/2018 33

Basic Format of a JCL : JCL FIELD NAMES 1. 2. 3. 4. Identifier field NAME field OPERATION field PARAMETER field – Positional – Keyword 5. COMMENT field ER/CORP/CRS/OS 02/003 -1 3/19/2018 34

JCL STATEMENT FORMAT //P 123 JOB 1234, AMLAN, CLASS=E JOBSTATEMENT Name Parameters Operation Identifier Comment ER/CORP/CRS/OS 02/003 -1 3/19/2018 35

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 col 1 • Name • One to eight alphanumeric , starting with a letter char. Starts from col 3. Valid chars A-Z, 0 -9 or national characters ( # , @ , $ ) ER/CORP/CRS/OS 02/003 -1 3/19/2018 36

Basic Format of a JCL : . . . – Operation • A valid operation code, such as JOB, EXEC or DD. Must be preceded and followed by a space. – Parameters • One or more parameters depending on the operation. Individual parameters are separated from one another by commas, no intervening spaces. – Comments • comments may follow parameters, preceded by one space and not extending beyond col 71 ER/CORP/CRS/OS 02/003 -1 3/19/2018 37

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 all positional parameters have been coded, order of keyword parameters immaterial ER/CORP/CRS/OS 02/003 -1 3/19/2018 38

JCL subparameters : • DCB=(DSORG=PO, LRECL=80, BLKSIZE=6160) • DCB=(DSORG=PO) DCB=DSORG=PO • DISP=(, DELETE) Comma place holders are required only for missing positional subparameters. ER/CORP/CRS/OS 02/003 -1 3/19/2018 39

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 //SYSUT 2 DD DSNAME=. . . , DISP=. . . , // UNIT=SYSDA, VOL=SER=MPS 800, // SPACE=(CYL, (10, 5, 2)), // DCB=DSORG=PO ( X ) Avoid continuing comments from line to line. ER/CORP/CRS/OS 02/003 -1 3/19/2018 40

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 comment statements that document a job thoroughly • Name, date of coding, what each job step does, any special processing requirements • Don’t forget to update comments ! ER/CORP/CRS/OS 02/003 -1 3/19/2018 41

JCL statements JOB Job identification EXEC Instruction for execution DD Source of data to operate ER/CORP/CRS/OS 02/003 -1 3/19/2018 42

JOB STATEMENT ACCT NAME MSGLEVEL MSGCLASS COND USER PASSWORD TIME CLASS NOTIFY TYPRUN PRTY RESTART REGION PERFORM ER/CORP/CRS/OS 02/003 -1 3/19/2018 43

IMPORTANT JOB PARAMETERS positional parameters ( a/c inf ), name ex. //INFOSYSA JOB (A 123), AMLAN • All these parameters are optional as far as JCL is concerned, they are probably required by your installation. ER/CORP/CRS/OS 02/003 -1 3/19/2018 44

IMPORTANT JOB PARAMETERS keyword parameters ( CLASS ) ex. //INFOSYSA 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. ER/CORP/CRS/OS 02/003 -1 3/19/2018 45

IMPORTANT JOB PARAMETERS keyword parameters ( MSGCLASS ) ex. //INFOSYSA 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. ER/CORP/CRS/OS 02/003 -1 3/19/2018 46

IMPORTANT JOB PARAMETERS keyword parameters ( MSGLEVEL ) ex. //INFOSYSA JOB MSGLEVEL=(1, 1) • MSGLEVEL(jcl, allocations) specifies the printing of JCL statements 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) ER/CORP/CRS/OS 02/003 -1 3/19/2018 47

keyword parameters ( MSGLEVEL ) MSGLEVEL=(X, Y) Where X is 0 thru 2 , Y is 0 thru 1 X = 0 , Lists Job statements only. X = 1 , Lists all User JCL + All catalogued procedures. X = 2 , Lists all User JCL but no catalogued procedures. Y = 0 , No Initiator/terminator messages to be listed. Y = 1 , All initiator/terminator messages to be listed. ER/CORP/CRS/OS 02/003 -1 3/19/2018 48

IMPORTANT JOB PARAMETERS keyword parameters ( NOTIFY ) ex. //INFOSYSA JOB NOTIFY=INFOSYS • NOTIFY notifies you at a time-sharing terminal when the job is completed. ER/CORP/CRS/OS 02/003 -1 3/19/2018 49

IMPORTANT JOB PARAMETERS keyword parameters ( TYPRUN ) ex. //INFOSYSA 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 held until the operator releases it. • TYPRUN = JCLHOLD(JES 2 only) similar to HOLD but the difference is it is checked while it is not with the HOLD option. • TYPRUN = COPY(JES 2 only) lists or duplicates the lines placed in the JOB statement to the class assigned in the MSGCLASS parameter and suppresses execution. 3/19/2018 ER/CORP/CRS/OS 02/003 -1 50

SOME OTHER keyword JOB PARAMETERS • PRTY=priority : is related to the CLASS parameter. It assigns priority 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=STEP 3 : Forces the JOB execution to start from STEP 3. ER/CORP/CRS/OS 02/003 -1 3/19/2018 51

SOME OTHER keyword JOB PARAMETERS • ADDRSPC=REAL : It is used to specify whether the program is to use REAL or VIRTual ADDRess SPa. Ce. Default is Virtual. If Real is coded then the REGION parameter is also to be coded. • REGION=96 K : 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 Day 2. ER/CORP/CRS/OS 02/003 -1 3/19/2018 52

Errors • JCL syntax errors. JOB will not be executed • JCL allocation errors. JES 2 -subsequent steps will not get executed. JES 3 -detects errors in the beginning. ER/CORP/CRS/OS 02/003 -1 3/19/2018 53

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 a being impossible or unacceptable. ER/CORP/CRS/OS 02/003 -1 3/19/2018 54

Causes of Abend Failures ·Logic error ·JCL error ·Resource unavailability ·Exceeding limits (Time or Space on DASD) ·Hardware Malfunction ·User ABENDS ·Operator intervention ·Operating System failure ER/CORP/CRS/OS 02/003 -1 3/19/2018 55

That’s all for DAY 1 ER/CORP/CRS/OS 02/003 -1 3/19/2018 56