What are the various stages of Job processing?

• Submit JOB - Submitting the JOB for processing.
• JOB Entry System - Accepts the job for processing.
• JOB Execution Ready - JES will replace all symbolic parameters, PROCS, convert the total JOB into a single JOB, and makes execution ready with all parameters.
• JOB Queuing - JES decides the priority of the JOB execution based on CLASS and PRTY parameters in the JOB statement. If some jobs are at a higher priority, then those jobs get executed first, and the current JOB is on hold. The queue set for execution is called JOB Queue.
• Job Execution - When the JOB reaches its highest priority, JOB gets active for execution from the JOB queue.
• JOB syntax and File Validation - The JCL errors and file validations are handled in this step.
  • If there are no errors, the JOB execution starts immediately, writes the logs to SPOOL, generates the output and completes the JOB execution successfully.
  • If there are errors, JOB fails with JCL errors.
• Purging - When the JOB is completed (Successfully/Unsuccessfully), the allocated resources and spaces are released.

How does the JCL specify the JOB to OS?

In JCL, the job statement specifies the key parameters to OS, such as job name, accounting information, and priority, which the OS uses to manage and execute the job.

In Job processing, what happens in conversion stage?

This stage includes syntax checking, parameter validation, and the creation of job control blocks, preparing the job for execution by the Job Entry Subsystem (JES).

In Job processing, what happens in Execution stage?

In the job execution stage, the Job Entry Subsystem (JES) runs the job's specified tasks. The system allocates necessary resources, executes the program steps coded in the JCL, handles input and output operations, and manages error handling. Upon completion, it collects and routes the output to the appropriate destinations.

How do you submit a job for execution?

To submit a job for execution in JCL, you use the SUBMIT or SUB command. This command sends the job to the Job Entry Subsystem (JES) for processing.

How to verify the job output?

To verify the job output in JCL, you check the job log using tools like SDSF (System Display and Search Facility) or similar mainframe utilities. These tools allow you to view the job's execution results, including messages, return codes, and any generated reports or files.

How does JCL act on a COBOL code?

JCL acts on a COBOL code by specifying the steps and resources needed to compile, link-edit (if necessary), and execute the COBOL program.

What event triggers job execution in a system?

The job execution is triggered by submitting the job for processing. This submission can be initiated manually by a user entering a submit command or automatically based on predefined schedules.

I have multiple jobs ( JCLs with several JOB cards ) in a member. What happens if I submit it?

All the jobs gets submitted in the order how they coded.

Frequently Asked Questions -

What are the different stages of job processing in JCL?
Explain how JCL execution works?

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