007 – Introduction to JCL – SPECIAL DD STATEMENTS

SOURCE – http://www.geocities.com/srcsinc/drona/programming/languages/jcl/jcl.html

SPECIAL DD STATEMENTS

1. DUMMY DSN=NULLFILE

2. Concatenating Data sets

3. Passing data to cobol program using – SYSIN DD *

4. SYSOUT

5. SYSUDUMP

6. SYSADUMP

1. DUMMY or DSN=NULLFILE

Some times we need to testing of program, without using actual datasets. Then we can use DUMMY or DSN=NULLFILE. If we use DUMMY, operating system simulates the presence of a file. When you reading Operating system sends end of file request to program.

Example JCL –>

//MYJOB JOB (W345),’KRISHNA REDDY’

//STEP1 EXEC PGM=COBPROG

//INFILE DD DUMMY

2. CONCATENATING DATA SETS

In JCL , we can concatenate different files by giving their name one after another. All data sets concated must be of the same type. For example, partitioned data sets can be concatenated only with partitioned data sets.

Example JCL –>

//MYJOB JOB (W345),’KRISHNA REDDY’

//STEP1 EXEC PGM=COBPROG

//INFILE DD DSN=TEST.GLOB.FILE1

// DSN=TEST.GLOB.FILE2

// DSN=TEST.GLOB.FILE3

In program , we will read it as an single file. concatination of three files done by operating system.

Maximum of 255 sequential data sets can be concatenated together Maximum of 16 partitioned data sets can be concatenated together

3. PASS DATA TO COBOL PROGRAM USING – SYSIN DD *

This is the one of the way of passing data to program. There are two syntax’s to pass data.

Syntax1 ->

//MYJOB JOB (W234),’RAMESH’

//STEP1 EXEC PGM=COBPROG

//SYSIN DD * /*

Syntax2 ->

//MYJOB JOB (E345),’KRISHNA REDDY’

//STEP1 EXEC PGM=COBPROG

//SYSIN DD DATA /*

4. SYSOUT

The SYSOUT parameter is used to send the output which is generated during job execution.

Syntax ->

//ddname DD SYSOUT=class

EXAMPLE JCL ->

//MYJOB JOB (R456),’KRISHNA REDDY’

//STEP1 EXEC PGM=COBPROG

//INFILE DD SYSOUT=A

In this example, COBPROG is executed and all generated outputs are directed to class ( here it is letter A)

If * used with SYSOUT (SYSOUT=*) parameter, The class assigned to the MSGCLASS parameter will be used to SYSOUT.

5. SYSUDUMP

SYSUDUMP is used to dump the content of various registers, variables and datasets acccessed at the time of abnormal termination, into a dataset. The dump is in hexadecimal.

Syntax –> //SYSUDUMP DD …..

EXAMPLE JCL –>

//MYJOB JOB (W345),’RAMESH’

//STEP1 EXEC PGM=COBPROG

//SYSUDUMP DD DSN=TEST.PROD.LIB

6. SYSABEND

SYSABEND is used to dump the contents of various registers variables , datasets accessed and The nucleus at the time of abnormal termination. The dump is in hexadecimal.

Syntax –> //SYSABEND DD …..

EXAMPLE JCL –> //MYJOB JOB (WE345),’KRISHNA REDDY’

//STEP1 EXEC PGM=COBPROG

~ by munchy on July 4, 2008.