JCL (Job Control Language) Interview Questions

tutorial and example
tutorial and example

1) What is JCL?

JCL refers to Job Control Language. It is a command language which describes job (unit of work) for the Multiple Virtual Storage (MVS) operating system. It is mainly used in Operating System in the IBM Mainframe computer.

2) What is JES?

JES stands for Job Entry Subsystem which is a subsystem of MVS mainframe. It manages the jobs which the system performs. JES receive job into operating system, make schedule processing on behalf of priority and control the output.

3) What are the job processing steps in CLS?

JCL performs series of steps to complete a job:

JCL dir

4) What are different types of job control statements?

Following are the different types of job control statements in JCL:

  • JOB Statement.
  • DD Statement.
  • EXCE Statement.

5) What is Job Statement?

Job Statement is the control statement in a JCL. It provide identity to the job in operating system. It uses parameter to help operating system to allocating right schedule.

Syntax:

6) What is //?

JCL statement must start with ‘//’symbol. It is predefine rule that must follow to execute the JCL statement. If we don’t use it, the statements throw an error.

7) What is EXEC Statement?

EXEC (execute) statement is used to identify which job step is to be executed and tells to the system how the job is to proceeds. The EXEC statement used at the beginning of each steps in a job or procedure.

Syntax:

8) What is DD Statement in JCL?

DD(Data definition) statement defines each data sets used in JCL job when it runs. DD statements describe name of program (ddname) actual name of data set and its location, initial and final status of data set (disposition).

Syntax:

9) What are the various DD parameters?

DD statement uses one or more parameter based on requirements. Each parameter is separated by using comma. The various parameters are:

  • DSN
  • DISP
  • DCB
  • SPACE
  • UNIT
  • VOL
  • SYSOUT

10) Define JOBLIB Statement.

JOBLIB is a private library. It is used to identify location of program which is executed in JCL. The JOBLIB statement is placed after the JOB statement and before EXCE statement.

Syntax:

11) Define STEPLIB Statement.

The STEPLIB statement is used to specify the program library where the program to be executed within a job step. It is placed after EXCE statement and before DD statement.

If we use both JOBLIB and STEPLIB in a single statement, STEPLIB statement overrides JOBLIB statement.

Syntax:

12) What is the difference JOBLIB and STEPLIB statement?

JOBLIB STEPLIB
JOBLIB statement can’t be cataloged. STEPLIB can be cataloged.
JOBLIB is used for an entire job. STEPLIB is used for an individual job step.

13) Define INCLUDE Statement.

INCLUDE statement is used to identify a member of PDS that can be included to a JCL statements using INCLUDE statement.

Syntax:

14) Define JCLLIB Statement.

JCLLIB statement is used to identify the name of private libraries that the system used in the job. JCLLIB statement searched in the given order to locate the programs, procedure and INCLUDE members used in job. JCLLIB statement is applied after JOBLIB statement and before EXCE statement. Only one JCLLIB statement is used in JCL.

Syntax:

15) What is JCL procedure?

JCL procedures are set of statement inside JCL group. It is used to perform specific function. Procedures are used to achieve parallel execution of programs by using multiple input file.