JCL Interview Questions and Answers Explanation

10/07/2009 No Comment

JCL Question Answers, Concepts, Explanation.

What does the keyword DCB mean and what are some of the keywords ?
Answer : Associated IT DCB stands for data control block; it is a keyword for the DD statement used to describe Data Sets Keywords associated with it are BLKSIZE, DEN, LRECL and RECFM.

What is the difference between BLKSIZE and LRECL?
Answer : BLKSIZE specifies the number of bytes

What are all the JCL statements used in JCL? & What are the JCL statements you have coded so far?

Answer : //JOB marks the beginning of a job, contains job information //EXEC marks the beginning of a job step, identifies program, cataloged procedure to be executed //DD (data definition), identifies a data set and its attributes //OUTPUT (specifies processing options for system output(sysout) data sets) //(null) (end of job) /* (end of data placed in input stream) //PROC (procedure) //PEND (procedure end) //* (comment)

What is the difference between the positional parameters & keyword parameters, give examples where they are used?

Answer : Positional Parameters are:- a).Sequence predetermined b) Parameters separated by commas c) Omitted parameters must be indicated by two consecutive commas. d) Installation dependent EX: //JOBNAME JOB (DIS, TRG.TRGGLO.NL.BATCH), ‘PGM1) //SETP01 EXEC PGM=MYPROG Keyword parameters are Predetermined words are referred to as key word Parameters. Any sequence is permitted, separated by commas. Follow positional parameters. Format is = EX: //JOBNAME JOB (DIS, TRG, N1, BATCH), MSGLEVEL=(1,1), // MSGCLASS=X, NOTIFY=QZ6P03T, TYPRUN=SCAN

What are the operands coded in a JOB statement?

Answer : All the Positional and Key word parameters in the JOB statement. Accounting Information, MSGCLASS, CLASS, MSGLEVEL, NOTIFY, USERID, PASSWD, COND, REGION, RESTART.

How many characters can be coded for a job name? What were you coding as a job name?

Answer : 8 Characters, Usually JOBNAME will be like User-id + 1 Char

What is the difference between the Comment statement and the Comments?How they were coded in a JCL?
Answer : //* is the comment statement and it starts from column number 1 Anything that is written after 71st column is taken as a comment.

How will you check the syntax of the JOB without executing it?

Answer : Can use JSCAN.Code TYPRUN=SCAN and submit the JCL for syntactical errors.

What are all the parameters needed in a DD statement to create a data set thru JCL? How a Partitioned data set is created thru JCL?
Answer : DISP (Disposition): The DISP parameter describes the status of a data set to the system, what is to be done with the data set at the end of the job step, and what to do with the data set if the step terminates abnormally DCB (Data control black) : DCB=(LRECL=NN, BLKZIZE=YY,RECFM=Z,DSORG=MM) Z can be F, FB, V, VB MM Can be PS (physical sequence) PO (partitioned) DSN (Data set name) : UNIT : Identifies device of data set Space :

How is the Catalog procedure called from a JCL, if it is lying in your own data sets ?

Answer : STEP1 EXEC PROC=PROC1 The library in which PROC1 is present should be mentioned in PROCLIB.

What is the difference between the In-stream Procedure & Catalog Procedure?Answer : In-stream Procedures begin with a PROC stmt and must be terminated by a PEND stmt. (PEND can also be coded for a cataloged Procedure, but it isn’t required) The PENC stmt coded as : //Option-name PEND comments The In-stream Procedure is placed following the JOB statement of the JOB. Up to 15 In-stream Procedures can be included in a single job. Each In-stream Procedure may be invoked several times with in the job. //QZ5P13TD JOB (18636), ‘HARISH’, CLASS=A //RUN PROC In-stream procedure starts from here //GO EXEC PGM=ONE //SYSOUT DD SYSOUT=A //PEND //STEP1 EXEC RUN procedure is used like .. A set of JCL stmt’s consisting of a PROC stmt and one or more EXEC and DD stmt (steps), which is placed in a procedure library. It executed by an EXEC (procedure) stmt in another data set (called the execution JCL). Advantages : Saves time, prevents errors.

What is the Symbolic parameter?What for it is needed? Where it is most commonly used?
Answer : Any parameter that can vary with each execution is a good candidate for definition of a symbolic parameter. Use of symbolic parameter make the procedure more flexible. This prevents the procedure to be modified each and every time a small and recurring change is needed at a place. //DD1 DD DSNAME=&SYSUID..PROFILE,DISP=(NEW,KEEP),

Can you explain the DISP Parameter in detail? What are the default DISP Parameters?

Answer : a. Current Status NEW – Default OLD – exclusive SHR – Simultaneously MOD – b. Normal Disposition KEEP – Default if DISP = SHR, OLD, MOD DELETE – Default if DISP = NEW CATLG c. Abnormal Termination – same as Normal Disposition

What is the difference between the Refer-back & Overriding parameters?How are they coded in a JCL?

Answer : Refer back option is a reference to an earlier DD statement in the job or in cataloged or in in-stream procedure called by a job step. KEYWORD = reference. //JOB1 JOB .. //STEPA EXEC .. //DD1 DD DSN=REPORT ... // DD4 DD DSN=*.DD1 //JOB2 JOB .. //SETP1 EXEC .. //DDA DD DSN=D578.POL.PUBS01 .. //STEP2 EXEC .. //DDB DD DSN=*.STEP1.DDA Over riding parameters. In an In-stream or Cataloged procedures, the DD names mentioned in the JCL will override the ones in the procedures. //JOB1 JOB .. //STEPA EXEC PROC1 //PS1.DD1 DD DSN=SAMPLE.PUB,DISP=SHR //PS2.DD2 DD DSN=SAMPLE.PUB1,DISP=SHR Proc PROC1 contains... //PS1 EXEC PGM=ABC //* //DD1 DD DSN=DUMMY //SYSOUT DD SYSOUT=* // //PS2 EXEC PGM=DEF //* //DD1 DD DSN=SAMP.PROG.DATA,DISP=SHR //DD2 DD DSN=SAMP.PROG.DATA1,DISP=SHR // SYSOUT DD SYSOUT=*

How do you pass parameters to a program coded in an EXEC statement?

Answer : Through PARM Clause coded on the EXEC statement. The parameters have to be defined in the Linkage Section of COBOL program.

What is a GDG?
Answer : A GDG is Generation Data Group. GDG’S allow users to create multiple data sets with the same base name distinguished by a logical number. History files can be referenced by using a negative generation number. GDG base can be created using a utility (IEBPROGM or IDCAMS) With (+1) we will be creating. EX: //OUTDD DD DSN=QZ6P03T.ARUN.MASTER(+1) (Create new data set) //INDD DD DSN=QZ6P03T.ARUN.MASTER(+0) (Reference most current data set). Yes - GDG can be sequential, direct, or partitioned Organization and can be reside on tape or direct-access volumes GDG must always be cataloged

What are the parameters used in creating a GDG? Explain in detail? Can you alter the parameters for the existing GDG?If yes, How? Creating a Model Data Set Label (or control block, DSCB)
Answer : This label is a data set which contains DCB attributes and is usually referred to in the DCB parameter when creating new GDG data sets. Most shops create the model DSCB with no DCB attributes.

What for the Model data set used for a GDG? How much space will you give to the Model Data set ?
Answer : The system needs an existing data set to serve as a model supplying the DCB parameters for the GDG to you want to create. The system uses the data set label to obtain the DCB sub-parameters, and the model is called the DSCB for reasons lost to history. Need not specify any space while creating a model data set.

How many Maximum generations can be created for a GDG?> How will you create a Generation data set ?

Answer : The maximum number of GDG versions that can be created is 255. A GDG data set is created with “(+1)” appended to the name of the GDG base.

What is the E37 error?How will you resolve it with out losing a single byte of data?

Answer :  This Error comes when you save the data set after editing it) Insufficient Space.

What is SOC7 abend ?How do you resolve it?

Answer : Data Exception. Eliminate the bad data by debugging the program.
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