Defining files to the operating system

Depending on the operating system, this system data definition can take any of the following forms:

• DD statement for MVS JCL.
• ALLOCATE command under TSO.
• Environment variable for z/OS® or z/OS UNIX. The contents can define either an MVS data set or a file in the z/OS UNIX file system.

The following examples show the relationship of a FILE-CONTROL entry to the system data definition and to the FD entry in the FILE SECTION:

• JCL DD statement:

  
      (1)
  //OUTFILE  DD  DSNAME=MY.OUT171,UNIT=SYSDA,SPACE=(TRK,(50,5))
  /*
  

• Environment variable (export command):

  
            (1)
  export OUTFILE=DSN(MY.OUT171),UNIT(SYSDA),SPACE(TRK,(50,5))
  

• COBOL code:

  
  ENVIRONMENT DIVISION.
  INPUT-OUTPUT SECTION.
  FILE-CONTROL.
      SELECT CARPOOL
        ASSIGN TO OUTFILE (1)
        ORGANIZATION IS SEQUENTIAL.
  . . .
  DATA DIVISION.
  FILE SECTION.
  FD CARPOOL       (2)
      LABEL  RECORD STANDARD
      BLOCK  CONTAINS 0 CHARACTERS
      RECORD CONTAINS 80 CHARACTERS
  

(1)

The assignment-name in the ASSIGN clause points to the ddname OUTFILE in the DD statement or the environment variable OUTFILE in the export command:

• //OUTFILE  DD DSNAME=OUT171 . . ., or
• export OUTFILE= . . .

(2)

When you specify a file file-name in a FILE-CONTROL entry, you must describe the file in an FD entry:

SELECT CARPOOL
. . .
FD CARPOOL