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Top 20 Basic JCL interview questions and answers
1. What is JCL?
JCL stands for Job Control Language. It is a scripting language used on mainframe systems to control the execution of batch jobs.
2. What are the different types of JCL statements?
There are three types of JCL statements:
– JOB statement: Defines the start of a job and provides job-related information.
– EXEC statement: Specifies the type of program or procedure to be executed.
– DD statement: Defines the input, output, and intermediate data sets.
3. What is a PROC in JCL?
A PROC is a procedure that contains a set of JCL statements that can be reused in multiple jobs. It simplifies job management and promotes code reusability.
4. What is the purpose of the TIME parameter in the JOB statement?
The TIME parameter specifies the maximum time allowed for a job to execute. If a job exceeds this time limit, it is terminated.
5. How do you submit a JCL job for execution?
JCL jobs can be submitted for execution using the JES (Job Entry Subsystem) command ‘SUBMIT’. The syntax is SUBMIT jobname.
6. What is a dataset in JCL?
A dataset is a logical unit that represents a physical file or collection of files on a mainframe system. It is defined in the DD statement of the JCL.
7. What is the purpose of the DISP parameter in the DD statement?
The DISP parameter specifies the disposition of a dataset after job execution. It defines whether the dataset should be retained, deleted, or cataloged.
8. What is the purpose of the COND parameter in the EXEC statement?
The COND parameter specifies a condition under which a step should be bypassed. If the condition is not met, the step is executed.
9. Explain the use of the SORT statement in JCL.
The SORT statement is used to sort data sets in a specified order. It provides various sorting options, such as sorting by specific fields or using a particular sort algorithm.
10. How do you specify input and output datasets in JCL?
Input and output datasets are defined using the DD statement. The DD statement specifies the dataset name, file organization, record format, and other attributes.
11. What is the purpose of the SYSIN DD statement?
The SYSIN DD statement specifies the input source for the job step. It is commonly used to provide input data for utility programs, such as SORT or IDCAMS.
12. How can you conditionally execute a job step in JCL?
You can conditionally execute a job step by using the COND parameter in the EXEC statement. It specifies a condition that must be met for the step to be executed.
13. What is the purpose of the NOTIFY parameter in the JOB statement?
The NOTIFY parameter specifies the user or group to be notified when the job execution completes. It enables tracking of job completion and handling of job-related events.
14. What are the different data set organizations supported in JCL?
JCL supports various data set organizations, including sequential (PS), partitioned (PO), and indexed (IS or VSAM) datasets.
15. How do you override default system values in JCL?
Default system values in JCL can be overridden by specifying the desired values in the JCL statements. For example, overriding the default job priority or time limit.
16. What does a job return code indicate in JCL?
A job return code indicates the status of the job execution. A return code of ‘0’ indicates successful completion, while non-zero codes indicate errors or abnormal terminations.
17. How do you specify the execution order of multiple steps in JCL?
The execution order of steps in JCL is determined by their position in the job stream. The first step comes after the JOB statement, followed by subsequent steps.
18. What are function symbols in JCL?
Function symbols are placeholders in JCL that represent dynamically generated values. They can be used to incorporate date, time, job name, or other system-supplied information.
19. What is the purpose of the IEBGENER utility in JCL?
The IEBGENER utility is used to copy or generate a new dataset from existing input datasets. It is commonly used for dataset manipulation and generation.
20. How do you terminate a running JCL job?
A running JCL job can be terminated using the JES command ‘CANCEL’. The syntax is CANCEL jobname. However, only authorized users with the necessary privileges can cancel jobs.
Top 20 Advanced JCL interview questions and answers:
1. What is JCL?
JCL (Job Control Language) is a scripting language used on IBM mainframe systems to define and execute jobs.
2. How can you override the position and length of an input file?
You can use the DD statement’s OFFSET and LENGTH parameters to override the position and length of an input file.
3. What is the purpose of JCLLIB statement?
JCLLIB statement is used to specify the private library that contains procedure (PROC) and cataloged procedures.
4. How can you identify if a job has abended or terminated successfully?
The completion code (RC) or condition code (CC) returned by the job step indicates whether a job has terminated successfully or abended.
5. What are system abends and user abends in JCL?
System abends are caused by an error in the system software, while user abends occur due to errors in the user-generated programs.
6. What is the difference between TYPRUN=SCAN and TYPRUN=HOLD?
When TYPRUN=SCAN is used, the system checks the syntax and errors in the JCL without actually executing it. TYPRUN=HOLD holds any output produced during job execution.
7. What is the significance of DISP parameter in JCL?
The DISP (Disposition) parameter specifies the disposition of a dataset. It defines whether the dataset should be retained, deleted, or passed on to subsequent steps.
8. What are the different dataset organization types in JCL?
The different dataset organization types in JCL are sequential (SEQ), partitioned (PDS), and VSAM (Virtual Storage Access Method).
9. How can you specify multiple input datasets in a single DD statement?
By using the DSN parameter with an ampersand (&), you can specify multiple input datasets in a single DD statement.
10. What is the significance of the NOTIFY parameter in JCL?
The NOTIFY parameter defines the user or group to whom job completion or error messages should be sent.
11. What is the difference between INCLUDE and SET statements in JCL?
The INCLUDE statement is used to include a member of a PDS or a library, while the SET statement is used to define symbolic parameters.
12. How can you extract specific records from a dataset using JCL?
You can use the IF condition in JCL to extract specific records from a dataset based on specific criteria.
13. What is the purpose of the //* comment line in JCL?
The //* comment line is used to comment out a job step or statement, thereby excluding it from execution without deleting it.
14. What is a cataloged procedure in JCL?
A cataloged procedure is a reusable set of JCL statements or steps that can be referenced and executed by multiple jobs.
15. What is a SYSIN dataset in JCL?
The SYSIN dataset is used to provide input to the program specified in the job step.
16. What is the purpose of the COND parameter in JCL?
The COND parameter defines a condition under which a job step should be executed. If the condition is not met, the step is bypassed.
17. What is the significance of the PARM parameter in JCL?
The PARM parameter is used to pass values or parameters to a program specified in the job step.
18. What are the different types of JCL errors?
The different types of JCL errors include syntax errors, logic errors, and execution errors.
19. What is the significance of the MAXCC parameter in JCL?
The MAXCC (Maximum Condition Code) parameter specifies the maximum completion code that is acceptable for the job.
20. How can you include one JCL member in another JCL member?
By using an INCLUDE statement, you can include one JCL member in another JCL member.
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