1. Reserved Names

2. //TPEIN DD UNIT=TAPE,DSN=PR.FLE, // DISP=(OLD,KEEP,KEEP) DDNAME - one to eight alphanumeric characters. The first character must be alphabetic. The DDNAME comes from the external reference name in the SELECT Clause of the ENVIRONMENT DIVISION of a COBOL program. Reserved DDNAMES - The following DDNAMES are specifically recognized by the operating system for a specific data set and cannot be used for any other purpose: JOBCAT JOBLIB SYSABEND STEPCAT STEPLIB SYSUDUMP

3. //JOBLIB DD DSN=LIB.NAME, DISP=(SHR) //STEPLIB DD DSN=LIB.NAME, DISP=(SHR) JOBLIB and STEPLIB DD statements instruct the operating system to fetch the program named in the EXEC statement from the library specified in the JOBLIB or STEPLIB DD statement. They are used whenever a program resides in a library other than SYS1.LINKLIB. A JOBLIB DD applies to the entire job and, if present, is the first DD statement immediately following the job statement. A STEPLIB DD applies only to the particular job step and must be placed following the EXEC statement for the job step.

4. //JOBCAT DD DSN=CAT.NAME, DISP=(SHR) //STEPCAT DD DSN=CAT.NAME, DISP=(SHR) JOBCAT and STEPCAT DD statements instruct the operating system to use a private user catalog rather than the system catalog. A JOBCAT DD applies to the entire job and, if present, is placed following the job statement and any JOBLIB statement and before the first EXEC statement. A STEPCAT DD refers only to the particular job step and must be placed following the EXEC statement for the job step. 4

5. //SYSUDUMP DD SYSOUT=A //SYSABEND DD SYSOUT =A The SYSUDUMP DD statement provides a core dump of the program’s virtual storage partition in the event the job terminates abnormally. The SYSABEND DD statement provides a core dump of the entire system nucleus in addition to the above.

6. //CUSTBLG JOB,SMITH,PRTY=7,CLASS=A, // MSGLEVEL=(1,1),MSGCLASS=A //CALCBLG EXEC PGM=CALCBLG,TIME=2, // PARM=(CYCLE1,UPDATE) //SYSUDUMP DD SYSOUT=A //INMASTER DD DISP=(OLD,KEEP,KEEP), // DSN=BILLING.MASTER //PAYCHGS DD DISP=(OLD,DELETE,KEEP), // DSN=BILLING.CHANGES, // UNIT=DISK //TAXTBLS DD DISP=SHR,DSN=TAX.TABLES

7. //UPDMSTER DD DISP=(NEW,CATLG,DELETE), // DSN=BILLING.MASTER, // UNIT=TAPE, // DCB=(LRECL=160,BLKSIZE=3200), // DCB=RECFM=FB) //BLGFILE DD DISP=(NEW,PASS,DELETE), // UNIT=SYSDA,DSN=BILLING.PRINT, // SPACE=(TRK,(20,5),RLSE), // DCB=(LRECL=100,BLKSIZE=4000) // DCB=(RECFM=VB) //ISSBILLS EXEC PGM=ISSBILLS,TIME=(,30) //SYSUDUMP DD SYSOUT=A

8. //BLGRPT DD SYSOUT=A //BILLS DD SYSOUT=(H,,DP12) //BLGFILE DD DISP=(OLD,DELETE,CATLG), // DSN=BILLING.PRINT //

9. //CUSTBLG JOB,SMITH,PRTY=7,CLASS=A, // MSGLEVEL=(1,1),MSGCLASS=A //JOBLIB DD //JOBCAT DD //CALCBLG EXEC PGM=CALCBLG,TIME=2, // PARM=(CYCLE1,UPDATE) //STEPLIB DD //SYSUDUMP DD SYSOUT=A //INMASTER DD DISP=(OLD,KEEP,KEEP), // DSN=BILLING.MASTER //PAYCHGS DD DISP=(OLD,DELETE,KEEP), // DSN=BILLING.CHANGES, // UNIT=DISK //TAXTBLS DD DISP=SHR,DSN=TAX.TABLES

10. //UPDMSTER DD DISP=(NEW,CATLG,DELETE), // DSN=BILLING.MASTER, // UNIT=TAPE, // DCB=(LRECL=160,BLKSIZE=3200), // DCB=RECFM=FB) //BLGFILE DD DISP=(NEW,PASS,DELETE), // UNIT=SYSDA,DSN=BILLING.PRINT, // SPACE=(TRK,(20,5),RLSE), // DCB=(LRECL=100,BLKSIZE=4000) // DCB=(RECFM=VB) //ISSBILLS EXEC PGM=ISSBILLS,TIME=(,30) //SYSUDUMP DD SYSOUT=A

11. //BLGRPT DD SYSOUT=A //BILLS DD SYSOUT=(H,,DP12) //BLGFILE DD DISP=(OLD,DELETE,CATLG), // DSN=BILLING.PRINT //