Basic Job Scheduling Concepts

Learning Objective

By the end of this lesson, you will be able to explain the basic difference between submitting a job to run immediately and scheduling one to run automatically later.

Simple Explanation

Every SBMJOB example covered so far in this path submits a batch job to run essentially right away, waiting only on its job queue, covered in the Job Queues and Output Queues lesson, before starting. IBM i also supports scheduling a job to run automatically at a specific future time, or on a recurring basis, such as every night, without anyone needing to submit it manually each time.

At a basic level, a scheduled job entry specifies what to run and when, and IBM i itself submits that job automatically once the scheduled time arrives, rather than a person running SBMJOB by hand at that exact moment.

Why It Matters

Understanding that scheduling exists as a distinct concept from a manual SBMJOB explains how routine, repeating processes, such as a nightly report, actually run without someone remembering to submit them every single night. Recognizing this distinction also helps when investigating why a job ran: was it manually submitted, or did it start automatically based on a schedule.

Practical Example

Imagine the nightly order-processing job needing to run automatically every night at a specific time, without an operator needing to remember to submit it manually. A scheduled job entry specifies the program to run and the nightly time to run it, and IBM i itself submits that job as a batch job at the scheduled time each night, landing on a job queue and proceeding exactly like any other submitted job from that point onward.

This is a simplified, illustrative example rather than a specific real schedule, but it reflects a genuinely common, practical reason job scheduling exists on IBM i.

Common Confusions

"Once a job is scheduled, does it skip the job queue entirely?" No. A scheduled job still becomes a submitted batch job at its scheduled time, waiting on a job queue exactly like one submitted manually with SBMJOB, covered in the Job Queues and Output Queues lesson.

"Is scheduling only useful for jobs that repeat every day?" No, though repeating jobs are a common use. A scheduled job entry can also be set for a single specific future time, run only once, rather than necessarily repeating on a recurring basis.

"Do I need to learn a separate enterprise scheduling tool to understand this lesson?" No. This lesson covers IBM i's own basic scheduling concept at a beginner level. More advanced, separate enterprise scheduling tools exist but are beyond this introduction.

Quick Recap

• Scheduling lets a job run automatically at a specific future time, or on a recurring basis, without someone submitting it manually each time.
• A scheduled job still becomes a submitted batch job, waiting on a job queue, at its scheduled time.
• Scheduling can be set for a single future run or a recurring pattern.
• This lesson covers IBM i's own basic scheduling concept; separate enterprise scheduling tools are a more advanced topic beyond this introduction.

Try Asking the AI Tutor

Use the AI Tutor to ask follow-up questions about this lesson. For example, try asking:

• "How would I check whether a specific job ran because it was scheduled or because someone submitted it manually?"
• "What would happen if a scheduled job's scheduled time arrived while its job queue was already busy with other work?"