IBM-JCL Interview Questions & Answers

  1. Question 1. What Is Jcl ?

    Answer :

    JCL stands for Job Control Language

  2. Question 2. What Is Jcl ?

    Answer :

    JCL stands for Job Control Language

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  4. Question 3. What Is A Generation Data Group (gdg)?

    Answer :

    A generation Data Group is a group of chronologically or functionally related datasets. GDGs are processed periodically, often by adding a new generation, retaining previous generations, and sometimes discarding the oldest generation.

  5. Question 4. How Is Gdg Base Created?

    Answer :

    A GDG base is created in the system catalog and keeps track of the generation numbers used for datasets in the group. IDCAMS utility is used to define the GDG base for MVS/XA, and MVS/ESA. Older systems required that the IEHPROGM utility be used.

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  7. Question 5. What Do You Mean By Include Statement In Jcl?

    Answer :

    An INCLUDE statement identifies a member of a PDS that contains this set of JCL statements is called an INCLUDE group. The system replaces the INCLUDE statement with the statements in the INCLUDE group.

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  9. Question 6. What Are The Differences Between Jes2 & Jes3 ?

    Answer :

    JES3 allocates Data Sets for all the steps before the job is scheduled. In JES2, allocation of Data Sets required by a step is done only just before the step executes. JOB /EXEC/DD ALL PARAMETERS JOBLIB/STEPLIB PROCEDURES, PARAMETERS PASSING CONDITION VARIABLES ABEND CODES.

  10. Question 7. What Are The Kinds Of Job Control Statements?

    Answer :

    The JOB, EXEC and DD statement

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  12. Question 8. What Are The Maximum Number Of In-stream Procedures You Can Code In Any Jcl?

    Answer :

    15.

  13. Question 9. What You Mean By Skeleton Jcl?

    Answer :

    JCL, which changes during run time, that is the values for the JCL such as program name, dd name will change. The same JCL can be used for various jobs, equivalent to dynamic SQL.

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  15. Question 10. What Is Jcl

    Answer :

    It is an interface between operating system (MVS) & the application program. When two related programs are combined together on control statements, it is called job control language

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  17. Question 11. What Is The Purpose Of The Job Statement?

    Answer :

    The purpose of the JOB statement is to inform the operating system of the start of a job, give necessary accounting information and supply run parameters. Each job must begin with a single JOB statement.

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  19. Question 12. How Does One Identify A Job To The Operating System?

    Answer :

    A job is identified to the system by the use of job name. Jobnames can range from one to eight alphabetic characters. The first character must begin in column 3 and be alphabetic (A-Z). Jobs should be given unique names since duplicate jobnames will not execute until any job having the same jobname completes execution.

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  21. Question 13. 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.

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  23. Question 14. How Are In-stream Procedures (procs) Built?

    Answer :

    In-stream procedures are built by coding a set of statements and placing them after the JOB statement and before the EXEC statement. In-stream procedures begin with a PROC statement and end with a PEND statement. Up to 15 in-stream procedures can be included in a single job.

    Each in-stream procedures may be invoked several times within the job. In-stream procedures can use symbolic parameters in the same way as catalogued procedures.

  24. Question 15. What Does A Mainframe Compiler Output In The Object Deck And What Does The Linkage Editor Do With It?

    Answer :

    The compiler outputs the source code into the object deck in a form to be read by the linkage editor. The linkage editor combines the object dataset (object deck) from the compiler with machine language code for input/output and other tasks to create an executable load module.

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  26. Question 16. What Is Primary Allocation For A Data Set?

    Answer :

    The space allocated when the Data Set is first created.

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  28. Question 17. How Many Extents Are Possible For A Sequential File ? For A Vsam File ?

    Answer :

    16 extents on a volume for a Sequential File and 123 for a VSAM File

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  30. Question 18. What Is An Operation Exception Error?

    Answer :

    An Operation exception error indicates that an operation code is not assigned or the assigned operations not available on a particular computer model. The machine does not recognize the instruction or operation used. A possible reasons a subscript error. This error could also be caused by an attempt to read a file that was not opened a misspelled DD statement. The system completion code is 0C1.

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  32. Question 19. Why Do You Want To Specify The Region Parameter In A Jcl Step?

    Answer :

    To override the REGION defined at the JOB card level REGION specifies the max region size REGION=0K or 0M or omitting REGION means no limit will be applied

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  34. Question 20. What Does The Time Parameter Signify? What Does Time=1440 Mean?

    Answer :

    TIME parameter can be used to overcome S322 abends for programs that genuinely need more CPU time TIME=1440 means no CPU time limit is to be applied to this step

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  36. Question 21. How Is The Keyword Dummy Used In Jcl?

    Answer :

    For an output File DUMMY specifies that the output is to be discarded for input it specifies that the File is empty.

  37. Question 22. What Is The Meaning Of Data Definition Name (dd Name) And Data Set Name (dsn Name) In The Dd Statement?

    Answer :

    Data definition name is the eight character designation after the // of the DD statement It matches the internal name specified in the steps executing program In COBOL that’s the name specified after the ASSIGN in the SELECT ASSIGN statement Data Set name is the operating system (MVS) name for the File.

  38. Question 23. What Is The Purpose And Meaning Of The Time Keyword And What Jcl Statement Is It Associated With?

    Answer :

    TIME specifies the maximum CPU time allocated for a particular job or job step if TIME is in the JOB card, it relates to the entire job; if in the EXEC statement, it relates to the job step.

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  40. Question 24. What Is The Purpose And Meaning Of The Region Keyword And What Jcl Statement Is It Associated With?

    Answer :

    REGION specifies the maximum CPU memory allocated for a particular job or job step If REGION is in the JOB card, it relates to the entire job; if in the EXEC statement, it relates to the job step.

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  42. Question 25. What Is The Purpose Of The Parm Keyword In The Exec Statement?

    Answer :

    The value after the PARM= specifies control information to be passed to the executing program of the job step

  43. Question 26. What Is The Improvement To Cond= In The Latest Version Of Mvs?

    Answer :

    MVS now allows for an IF bracketed by an END IF around any job step to replace the COND= syntax Again, if the IF statement is true, the step is bypassed.

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  45. Question 27. What Is The Meaning Of The Exec Statement Keyword, Cond? What Is Its Syntax?

    Answer :

    COND specifies the conditions for executing the subsequent job step the value after the COND= is compared to the return codes of the preceding steps and if the comparison is true, the step is bypassed

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  47. Question 28. How Do You Designate A Comment In Jcl?

    Answer :

    The comment statement is //* followed by the comments.

  48. Question 29. What Are The Keywords Associated With Dcb? How Can You Specify Dcb Information? What Is The Os Precedence For Obtaining That Dcb Information, I.e. Where Does The System Look For It First?

    Answer :

    The keywords associated with the DCB parameter are LRECL, RECFM, BLKSIZE and DSORG The DCB information can be supplied in the DD statement The system looks for DCB information in the program code first.

  49. Question 30. What Is Mod And When Would You Use It?

    Answer :

    DISP=MOD is used when the Data Set can be extended, i.e., you can add records at the end of an existing Data Set

  50. Question 31. What Is The Difference Between Specifying Disp=old And Disp=shr For A Data Set?

    Answer :

    A DISP=OLD denotes exclusive control of the Data Set; DISP=SHR means there is no exclusivity.

  51. Question 32. Explain Concatenating Data Sets?

    Answer :

    Data Sets can be grouped in a DD statement one after another, eg in a JOBLIB statement where the load module can exist in one of many Data Sets.

  52. Question 33. What Is A Gdg? How Is It Referenced? How Is It Defined? What Is A Modeldscb?

    Answer :

    GDG stands for generation data group it is a Data Set with versions that can be referenced absolutely or relatively it is defined by an IDCAMS define generation data group execution.

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  54. Question 34. What Is Restart? How Is It Invoked?

    Answer :

    A RESTART is a JOB statement keyword it is used to restart the job at a specified s step rather than at the beginning.

  55. Question 35. What Is The Difference Between A Symbolic And An Override In Executing A Proc?

    Answer :

    A symbolic is a PROC placeholder; the value for the symbolic is supplied when the PROC is invoked, eg &symbol=value an override replaces the PROC’s statement with another one; it substitutes for the entire statement.

  56. Question 36. What Is A Proc? What Is The Difference Between An In Stream And A Catalogued Proc?

    Answer :

    PROC stands for procedure It is ‘canned’ JCL invoked by a PROC statement an in stream PROC is presented within the JCL; a catalogued PROC is referenced from a proclib partitioned Data Set.

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  58. Question 37. Describe The Dd Statement, Its Meaning, Syntax And Keywords.

    Answer :

    The DD statement links the external Data Set name (DSN) to the DDNAME coded within the executing program It links the File names within the program code to the File names know to the MVS operating system The syntax is // ddname DD DSN=Data Set name Other keywords after DSN are DISP, DCB, SPACE, etc .

  59. Question 38. Describe The Exec Statement, Its Meaning, Syntax And Keywords?

    Answer :

    The EXEC statement identifies the program to be executed via a PGM=program name keyword Its format is //jobname EXEC PGM=program name The PARM= keyword can be used to pass external values to the executing program.

  60. Question 39. Describe The Job Statement, Its Meaning, Syntax And Significant Keywords.?

    Answer :

    The JOB statement is the first in a JCL stream Its format is // jobname, keyword JOB, accounting information in brackets and keywords, MSGCLASS, MSGLEVEL, NOTIFIY, CLASS, etc .

  61. Question 40. What Is The Meaning Of Keyword In Jcl? What Is Its Opposite?

    Answer :

    A keyword in a JCL statement may appear in different places and is recognized by its name, eg MSGCLASS in the JOB statement The opposite is positional words, where their meaning is based on their position in the statement, eg in the DISP keyword the =(NEW,CATLG,DELETE) meaning are based on first, second and third position.

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  63. Question 41. What Are The Valid Dsorg Values ?

    Answer :

    PS – QSAM, PO – Partitioned, IS – ISAM

  64. Question 42. The Disp In The Jcl Is Mod And The Program Opens The File In Output Mode. What Happens ? The Disp In The Jcl Is Shr And The Pgm Opens The File In Extend Mode. What Happens ?

    Answer :

    Records will be written to end of file (append) when a WRITE is done in both cases.

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  66. Question 43. How To Change Default Proclib ?

    Answer :

    //ABCD JCLLIB ORDER=(ME.MYPROCLIB,SYS1.PROCLIB)

  67. Question 44. When You Specify Mutiple Datasets In A Joblib Or Steplib, What Factor Determines The Order?

    Answer :

    The library with the largest block size should be the first one.

  68. Question 45. What Happens If Both Joblib & Steplib Is Specified ?

    Answer :

    JOBLIB is ignored.

  69. Question 46. What Is Order Of Searching Of The Libraries In A Jcl?

    Answer :

    First any private libraries as specified in the STEPLIB or JOBLIB, then the system libraries such as SYS1.LINKLIB. The system libraries are specified in the link list.

  70. Question 47. What Is Steplib, Joblib? What Is It Used For?

    Answer :

    Specifies that the private library (or libraries) specified should be searched before the default system libraries in order to locate a program to be executed.

    STEPLIB applies only to the particular step, JOBLIB to all steps in the job.

  71. Question 48. How Do You Run A Cobol Batch Program From A Jcl? How Do You Run A Cobol/db2 Program?

    Answer :

    To run a non DB2 program,

           //STEP001 EXEC PGM=MYPROG

    To run a DB2 program,

           //STEP001 EXEC PGM=IKJEFT01
           //SYSTSIN DD *
           DSN SYSTEM(....)
           RUN PROGRAM(MYPROG)
           PLAN(.....) LIB(....) PARMS(...)
             /*
  72. Question 49. How Do You Overcome This Limitation?

    Answer :

    One way is to code SYSIN DD DUMMY in the PROC, and then override this from the JCL with instream data.

  73. Question 50. Can You Code Instream Data In A Proc ?

    Answer :

    No.

  74. Question 51. I Have A Cobol Program That Accepts Some Input Data. How Do You Code The Jcl Statment For This? ( How Do You Code Instream Data In A Jcl? )

    Answer :

           //SYSIN DD*
            input data
            input data
            /*
  75. Question 52. I Have Multiple Jobs ( Jcls With Several Job Cards ) In A Member. What Happens If I Submit It?

    Answer :

    Multiple jobs are submitted (as many jobs as the number of JOB cards).

  76. Question 53. How Do You Send The Output Of A Cobol Program To A Member Of A Pds?

    Answer :

    Code the DSN as pds(member) with a DISP of SHR. The disp applies to the pds and not to a specific member.

  77. Question 54. What Does Iebgener Do?

    Answer :

    Used to copy one QSAM file to another. Source dataset should be described using SYSUT1 ddname. Destination dataset should be described using SYSUT2. IEBGENR can also do some reformatting of data by supplying control cards via SYSIN.

  78. Question 55. How Do You Check The Syntax Of A Jcl Without Running It?

    Answer :

    TYPERUN=SCAN on the JOB card or use JSCAN.

  79. Question 56. What Is Cond=only ?

    Answer :

    Means execute this step only if any of the previous steps, terminated abnormally.

  80. Question 57. What Is Cond=even ?

    Answer :

    Means execute this step even if any of the previous steps, terminated abnormally.

  81. Question 58. What Does The Time Parameter Signify ? What Does Time=1440 Mean ?

    Answer :

    TIME parameter can be used to overcome S322 abends for programs that genuinely need more CPU time. TIME=1440 means no CPU time limit is to be applied to this step.

  82. Question 59. What Is S322 Abend ?

    Answer :

    Indicates a time out abend. Your program has taken more CPU time than the default limit for the job class. Could indicate an infinite loop.

  83. Question 60. What Are Sd37, Sb37, Se37 Abends?

    Answer :

    All indicate dataset out of space. SD37 – no secondary allocation was specified. SB37 – end of vol. and no further volumes specified. SE37 – Max. of 16 extents already allocated.

  84. Question 61. What Is A S0c4 Error ?

    Answer :

    Storage violation error – can be due to various reasons. e.g.: READING a file that is not open, invalid address referenced due to subscript error.

  85. Question 62. What Is ‘s0c7’ Abend?

    Answer :

    Caused by invalid data in a numeric field.

  86. Question 63. What Is Notcat ?

    Answer :

    This is an MVS message indicating that a duplicate catalog entry exists. E.g., if you already have a dataset with dsn = ‘xxxx.yyyy’ and u try to create one with disp new,catlg, you would get this error. the program open and write would go through and at the end of the step the system would try to put it in the system catalog. at this point since an entry already exists the catlg would fail and give this message. you can fix the problem by deleting/uncataloging the first data set and going to the volume where the new dataset exists(this info is in the msglog of the job) and cataloging it.

  87. Question 64. How Do You Override A Specific Ddname/sysin In Proc From A Jcl?

    Answer :

    // DSN=…

  88. Question 65. A Proc Has Five Steps. Step 3 Has A Condition Code. How Can You Override/nullify This Condition Code?

    Answer :

    Provide the override on the EXEC stmt in the JCL as follows:
    //STEP001 EXEC procname,COND.stepname=value
    All parameters on an EXEC stmt in the proc such as COND, PARM have to be overridden like this.

  89. Question 66. How Do You Skip A Particular Step In A Proc/job?

    Answer :

    Can use either condition codes or use the jcl control statement IF (only in ESA JCL)

  90. Question 67. How Do You Restart A Proc From A Particular Step?

    Answer :

    In job card, specify RESTART=procstep.stepname
    where procstep = name of the jcl step that invoked the proc
    and stepname = name of the proc step where you want execution to start

  91. Question 68. How Do You Create A Temporary Dataset? Where Will You Use Them?

    Answer :

    Temporary datasets can be created either by not specifying any DSNAME or by specifying the temporary file indicator as in DSN=&&TEMP.

    We use them to carry the output of one step to another step in the same job. The dataset will not be retained once the job completes.

  92. Question 69. What Is Disp=(new,pass,delete)?

    Answer :

    This is a new file and create it, if the step terminates normally, pass it to the subsequent steps and if step abends, delete it. This dataset will not exist beyond the JCL.

  93. Question 70. What Do You Do If You Do Not Want To Keep All The Space Allocated To A Dataset?

    Answer :

    Specify the parameter RLSE ( release ) in the SPACE e.g. SPACE=(CYL,(50,50),RLSE)

  94. Question 71. What Is The Dd Statement For A Output File?

    Answer :

    Unless allocated earlier, will have the following parameters: DISP=(NEW,CATLG,DELETE), UNIT , SPACE & DCB .

  95. Question 72. What Does A Disposition Of (mod,delete,delete) Mean ?

    Answer :

    The MOD will cause the dataset to be created (if it does not exist), and then the two DELETEs will cause the dataset to be deleted whether the step abends or not. This disposition is used to clear out a dataset at the beginning of a job.

  96. Question 73. How Do You Access A File That Had A Disposition Of Keep?

    Answer :

    Need to supply volume serial no. VOL=SER=xxxx.

  97. Question 74. What Does A Disposition Of (new,catlg,keep) Mean?

    Answer :

    That this is a new dataset and needs to be allocated, to CATLG the dataset if the step is successful and to KEEP but not CATLG the dataset if the step abends. Thus if the step abends, the dataset would not be catalogued and we would need to supply the vol. ser the next time we refer to it.

  98. Question 75. What Does A Disposition Of (new,catlg,delete) Mean?

    Answer :

    That this is a new dataset and needs to be allocated, to CATLG the dataset if the step is successful and to delete the dataset if the step abends.

  99. Question 76. How Many Extents Are Possible For A Sequential File ? For A Vsam File?

    Answer :

    16 extents on a volume for a sequential file and 123 for a VSAM file.

  100. Question 77. What Is Primary Allocation For A Dataset?

    Answer :

    The space allocated when the dataset is first created.

  101. Question 78. What Is The Difference Between Primary And Secondary Allocations For A Dataset?

    Answer :

    Secondary allocation is done when more space is required than what has already been allocated.

  102. Question 79. What Is The Difference Between The Cond Parameter Specified On The Exec Statement And The One Specified On The Job Statement ?

    Answer :

    COND parameter specified on EXEC statement determines whether step should be bypassed or executed.

    COND parameter defined on the JOB statement will determine whether Job should be terminated at a certain point or continued. When COND parameter is defined on the JOB statement, the system evaluates condition specified in the COND parameter before beginning of any job step and compares the code specified in the COND parameter with the return code of all previous jobsteps. If that condition is true, the rest of the job steps are bypassed.

  103. Question 80. How Can You Check For Syntax Or Jcl Errors Without Actual Execution Of A Job ?

    Answer :

    TYPRUN=SCAN should be specified on a job card

  104. Question 81. What Is Msglevel Parameter ?

    Answer :

    It is a keyword parameter which indicates what job output is to be written as a part of output listing. The following outputs can be requested: the Job statement;
    all input job control statements;
    allocation, disposition and allocation recovery messages(allocation/termination message)

    MSGLEVEL=(statements, messages)

    Statements:
    – 0 – only the job statement is to be written;
    – 1 – all input control statements, cataloged procedure statements and the internal representation of procedure statement parameters after symbolic parameters substitution are to be written;
    – 2 – only input job control statements are to be written;

    Messages:
    – 0 – No allocation/termination messages are to be printed unless the job terminates abnormally;
    – 1 – All allocation/termination messages are to be printed.

  105. Question 82. What Is A Msgclass Parameter?

    Answer :

    It is a keyword parameter which specifies the output class to which system messages for your job are to be routed. Output class is an alphabetic (A thru Z) or numeric (0 thru 9) character. The default for MSGCLASS parameter will be A. System messages and output data sets can be routed to the same output class. You can code the MSGCLASS parameter in the Job statement and the SYSOUT parameter on the DD statement.

  106. Question 83. How Does The System Determine The Priority Of A Job For Execution?

    Answer :

    First the system determines which job has the highest class. Each class has a job queue with jobs of different priorities. The system will select the job for execution that has the highest PRTY (0 thru 15) 15 is the highest priority.

  107. Question 84. What Is A Priority?

    Answer :

    It is a keyword parameter which specifies a job initiation priority within its job class. When the job is initiated, the system will convert the job’s priority into a dispatching priority so that job’s task can complete with other tasks for use of main storage and CPU resources.

  108. Question 85. What Is A Name?

    Answer :

    Name is a positional parameter which identifies the person or group responsible for a job.

  109. Question 86. What Does Cond=even Mean ?

    Answer :

    It means that this jobs step will be executed even if a previous step abnormally terminated.

  110. Question 87. What Does Cond=only Mean ?

    Answer :

    It means that this job step will be executed only if a previous step had abnormally terminated.

  111. Question 88. How Do You Specify A Cond Parameter For A Job Step So That The Step Will Never Be Executed?

    Answer :

    COND=(0,LE) or COND=(4095,GE).

  112. Question 89. What Is Cond Parameter?

    Answer :

    It is a keyword parameter which can be specified on the JOB or EXEC statements. COND consists of 3 sub parameters:

    code(0 thru 4095),logical operator, and step name of the step that is going to be compared.
    The purpose of the COND is to determine whether the step should be executed or bypassed. If condition specified in the COND parameter is true, the step is bypassed.

  113. Question 90. What Is A Temporary Data Set?

    Answer :

    Temporary data sets are used for storage needed only for the duration of the job. If the DISP parameter doesn’t delete the data set by the end of the job, the system will delete it. Deleting a tape data set dismounts the tape, whereas deleting a dataset on a direct-access volume release the storage. A data set is marked temporary by omitting the DSN parameter or by coding DSN=&&dsname. The system assign a unique name to the data set when the DSN parameter is omitted, and any subsequent steps using the dataset refer back to the DD statement.

  114. Question 91. What Is A Pds?

    Answer :

    PDS is a library type of data set organization consisting of Directory and Members. The directory consists of blocks, and each block is 256 bytes in length and can hold up to 5 members. Each member of the PDS is a sequential data set.

  115. Question 92. What Is A Contig?

    Answer :

    CONTIG requests the primary space be allocated only on contiguous tracks and cylinders that are all tracks on a cylinder are contiguous, and if more than one cylinder is needed, the cylinders are also contiguous. Always code CONTIG if track overflow is used.

  116. Question 93. What Is A Rlse?

    Answer :

    RLSE releases all unused space when the data set is closed. It permits you to allocate more space than perhaps, it needed without wasting space. Space is released only if the data set is not empty and if the data set is closed after being opened.

  117. Question 94. What Is The Purpose Of Space Parameter?

    Answer :

    It is a keyword parameter which should allocated on the DD statement for the output data sets stored on the disk. It consists of the following sub parameters:
    SPACE=(BLKS/CYL/TRK,(primary,secondary,index),RLSE,CONTIG)

  118. Question 95. What Is The Difference Between * And Data?

    Answer :

    DD * and DD DATA describe the input data which follows the above mention cards. If the input data contains record switch // in col 1 and 2 then DD Data should be used.

  119. Question 96. How Do You Describe The Input Data Which Is A Part Of The Input Job Stream?

    Answer :

    You should use either DD * or DD Data.

  120. Question 97. When Should Be Nl Be Specified As A Type Of Label Processing?

    Answer :

    NL should be specified when a program needs to process unlabeled tapes NL can also be specified when the program wants to create unlabeled tape because the system’s default action, in cases when parameter is not specified, will create IBM standard label. Non labeled tapes are often used for sending tapes to another installation. That way you don’t have to worry about the tape label corresponding to the standards at the other installation or about accidentally matching the volume serial number of an existing tape at the installation.

  121. Question 98. What Is A Label ?

    Answer :

    LABEL is a keyword parameter which can be specified on DD statement and consists of the following subparameters:

    LABEL=(Relative File #, Type of Label Processing)
    The LABEL parameter tells the type of label, the relative file number,and whether the data set is to be protected for input or output.

  122. Question 99. How Does The System Get Information About The Block Size?

    Answer :

    DCB info comes from :-
    1) Program – FD: BLOCK CONTAINS 3 RECORDS RECORD CONTAINS 100 CHARACTERS
    2) The label – like a tape
    3) From the VTOC – for Dasd
    4) From the JCL – DCB=BLKSIZE=nnn.

  123. Question 100. What Are The Parameters That Have To Be Coded On A Dd Statement In Order To Retrieve A Cataloged Data Set?

    Answer :

    The minimum parameters needed are DSN and DISP.

  124. Question 101. What Is Disp=pass ?

    Answer :

    PASS passes the data set on to subsequent job steps, and each step can use the data set once. It is a positional sub parameter of the DISP which could only be specified under normal termination action. Pass saves time because the system retains the data set location and volume information.

  125. Question 102. What Is Disp=mod ?

    Answer :

    DISP=MOD modifies a sequential data set. It is a convenient way to add data to the end of sequential dataset. If the data set doesn’t exist, the system changes MOD to NEW unless the VOL parameter request specific volume. When VOL is coded, the stem expects to find data set on the specified volume and terminates the step if it cannot find it. MOD is the usual way of extended data sets in to several direct-access volumes.

  126. Question 103. What Is Disp=shr ?

    Answer :

    DISP=SHR permits old data sets to be shared. SHR is identical to OLD except that several jobs may read the dataset concurrently in multiprogramming environments. SHR must be used only for input data sets; use OLD or MOD if data set is modified. Sharing data set is necessary because public libraries like SYS1.LINKLIB or the subroutine libraries should be available to every job in the system.

  127. Question 104. What Is A Disp?

    Answer :

    DISP is a keyword parameter which is defined on the DD statement and which consist of the following positional subparameters: DISP=(Status, Normal Disp, Abnormal Disp). The DISP parameter describes the current status of the dataset (old, new, or modified) and directs the system on the disposition of the data set (pass, keep, catalog, uncatalog, or delete) either at the end of the step or if the step abnormally terminates. DISP is always required unless the data set is created and deleted in the same step.

  128. Question 105. What Is The Difference Between Keyword And Positional Parameters ?

    Answer :

    Positional parameters are characterized by their position in the operand field in relation to other parameters.

    Keyword parameters are positional independent with respect to others of their type and consisting of a keyword followed by an equal sign and variable information.

  129. Question 106. What Is The Meaning Of Keyword In Jcl?what Is Its Opposite?

    Answer :

    A keyword in a JCL statement may appear in different places and is recognized by its name, eg MSGCLASS in the JOB statement The opposite is positional words, where their meaning is based on their position in the statement, eg in the DISP keyword the =(NEW,CATLG,DELETE) meaning are based on first, second and third position.

  130. Question 107. Describe The Exec Statement, Its Meaning, Syntax And Keywords.?

    Answer :

    The EXEC statement identifies the program to be executed via a PGM=program name keyword Its format is //jobname EXEC PGM=program name The PARM= keyword can be used to pass external values to the executing program.

  131. Question 108. Describe The Dd Statement, Its Meaning, Syntax And Keywords?

    Answer :

    The DD statement links the external Data Set name (DSN) to the DDNAME coded within the executing program It links the File names within the program code to the File names know to the MVS operating system The syntax is // ddname DD DSN=Data Set name Other keywords after DSN are DISP, DCB, SPACE, etc .

  132. Question 109. What Is A Proc?what Is The Difference Between An Instream And A Catalogued Proc?

    Answer :

    PROC stands for procedure It is ‘canned’ JCL invoked by a PROC statement An instream PROC is presented within the JCL; a catalogued PROC is referenced from a proclib partitioned Data Set.

  133. Question 110. What Is A Gdg? How Is It Referenced?how Is It Defined? What Is A Mode Ldscb?

    Answer :

    GDG stands for generation data group It is a Data Set with versions that can be referenced absolutely or relatively It is defined by an IDCAMS define generation datagroup execution.

  134. Question 111. Explain Concatenating Data Sets ?

    Answer :

    Data Sets can be grouped in a DD statement one after another, eg in a JOBLIB statement where the load module can exist in one of many Data Sets.

  135. Question 112. What Are The Keywords Associated With Dcb? How Can You Specify Dcb Information? What Is The Os Precedence For Obtaining That Dcb Information, Ie Where Does The System Look For It First?

    Answer :

    The keywords associated with the DCB parameter are LRECL, RECFM, BLKSIZE and DSORG The DCB information can be supplied in the DD statement The system looks for DCB information in the program code first

  136. Question 113. How Does Jcl Act On Code(if You Take A Cobol Program) ?

    Answer :

    There are certain set of divisions that interact with JCL.

    Identification Division- act as introductory part to JCL(program name, author,date etc no interacting code).

    Environment Division- now the story begins – JCL interacts with OS acc to need as it send request for Files under file operation.

    Data Division- after files are accessed, it works with them according to operations to READ or to PRINT files (with the help of OS).

    Procedure Division- it contains various actions taken on files eg to close files that are being used.

  137. Question 114. What Is // ?

    Answer :

    It is an important symbol used in JCL statements. JCL statement must begin with this symbol. It is a predefined rule that must follow to execute the JCL statements otherwise it will through error. The JCL execution system first checks for that symbol at beginning of statements to be considered as JCL statement. Use without space between symbol and jobname. Every statement in jcl should start with //.to work properly. Use of it avoid any runtime exceptions.

  138. Question 115. What Are Hierarchy Levels In Jcl?

    Answer :

    Level describes the JCL statements. According to each action performed by each statement. Each statement of JCL consist of following keywords—

    NAME.
    FIELDS.
    OPERATIONS.
    OPERANDS.
    PARAMETERS.

    1. POSITIONAL.
    2. KEYWORD.

    COMMENTS IF ANY.

    Eg. //STEP007 EXEC PGM=JAMES BOND
    Here stepoo7 is the name,
    pgm is the keyword parameter,
    exec is the command,
    assign is the operation,
    jamesbond is the operand.

  139. Question 116. What Is Job Control Language?

    Answer :

    • A language for job description to MVS, OS/390 and VSE Operating Systems that run on IBM S/390 servers.
    • A set of statements that required for running a particular program is referred as a job step.
    • Without user interaction, job runs in background.
    • The OS manages the user requests to initiate the units of work.
    • Input data sets, such as files are the specific JCL statements to access. Once the resources are allocated for the job, the output data set is to be created or updated.
    • A set of JCL statements are stored as data set and will be started interactively.
    • A menu-like interface is provided by MVS and OS/390, known as ISPF to initiate and manage jobs.
  140. Question 117. Differentiate Between Addressing Mode And Run Mode?

    Answer :

    Addressing mode or Access Mode:

    • AMODE(24) indicates 24-bit addressing in the memory below the line.
    • AMODE(31) indicates 31-bit addressing in the memory above and below the line.
    • AMODE=ANY indicates either 24-bit or 31-bit addressing techniques. Run Mode or Residency Mode:
    • RMODE(24) indicates the program need to be loaded into the memory below the line.
    • RMODE(31) indicates the program need to be loaded into the memory either below or above the line.
    • RMODE=ANY indicates the program to load either in 24 bit or 31 bit memory.
  141. Question 118. What Does A Disposition Of (new,catlg,keep) For A Dsn Mean?

    Answer :

    • DISP NEW will allocate new memory space for disposition.
    • DISP CATLG will catalog the available data set once the step is successful.
    • DISP KEEP will retain the dataset. Catalog will not be kept when the step abends.
    • The above 3 operations always ensures that the data set is properly handled.
    • The operations are reliable to handle the data sets.
  142. Question 119. What Are Steplib And Joblib? What For They Are Used?

    Answer :

    • A library needs to be searched before the system library, for locating programs to execute by steps.
    • STEPLIB and JOBLIB are utilized for specifying the required library.
    • Not all steps are applied for both STEPLIB and JOBLIB.
    • STEPLIB is used only for a particular step.
    • JOBLIB is used for all the jobs
  143. Question 120. What Is The Difference Between The Positional And Keyword Parameters? Give Examples?

    Answer :

    • Positional Parameters are placed in a specific position.
    • It needs to be positioned within the operand field.
    • Example: Employee name in the Job card is a positional parameter at the Job level.
    • Keyword Parameters are not placed in a specific position or order.
    • Example: MSGLEVEL=(X,Y)
  144. Question 121. What Is The Purpose Of Disp Parameter?

    Answer :

    • DISP parameter is used for specifying the disposition of the data set.
    • The current status of the data set is specified at
      1. The beginning of the step.
      2. The successful execution of the step.
      3. Abnormal execution of the step.
    • DISP is assigned for two dispositions along with the status.
    • The notation of DISP is DISP = (Status, Normal Disposition, Abnormal Disposition).