INTRODUCTION TO JCL

CHAPTER - 1          Introduction

Job control language. It is a means of communication between a program that 
can be written in COBOL , ASSEMBER or PL/I and the MVS operating system. Without
a JCL, you cant able to run a job on MVS operating system.

Let us start with an example jcl, how it looks like, The following jcl is 
used to run an cobol program. I will explain in this chapter each and every 
line of this jcl. If you are already fimiliar with jcl, please skip first 
6 chapters. 

(First 1 - 6 chapters intended for beginners)

JCL , used to run a cobol program

//JOB1    JOB  (034D),'RAMESH KRISHNA REDDY',CLASS='A',PRTY=6
//STEP01  EXEC PGM=COBPROG.
//INFILE  DD   DSN=SED.GLOB.DES.INFILE,DISP=SHR
//OUTIFLE DD   DSN=SED.GLOB.DES.OUTFILE,
//             DISP=(NEW,CATLG,DELETE),
//             UNIT=DISK,
//             SPACE=(CYL,(1,5),RLSE),
//             DCB=(RECFM=FB,LERECL=70,BLKSIZE=700)




  
Now let us discuss JCL which we have seen.

Before explaining, I will explain few basics about JCL

All JCL statements can consists of up to five types of
fields

  // The two forward slashes are required at the beginning of each
     JCL statement in Columns 1 and 2.

  Name field - This is an optional field. If coded, should start at
               Column 3. It maximum length is 8.

  Operation field - Which indicates the operation that is to be performed

  Operand - This field must appear after Operation field. Must start at 16 
            column 

  Comments - Comments begin one space after the last operand. Our simple 
             example has no comments.



  
  
  //  Name      Operation             OPerand
   
  //  JOB1           JOB                  (034D),
                                          'RAMESH',
                                          CLASS='A',
                                          PRTY=6

  //   STEP01         EXEC                PGM=COBPROG

  //   INFILE         DD                  DSN=SED.GLOB.DES.INFILE,
                                          DISP=SHR
  //   OUTIFLE        DD                  DSN=SED.GLOB.DES.OUTFILE,
  //                                      DISP=(NEW,CATLG,DELETE),
  //                                      UNIT=DISK,
  //                                      SPACE=(CYL,(1,5),RLSE),
  //                                      DCB=(RECFM=FB,
  //                                      LERECL=70,BLKSIZE=700)