Job
A unit of batch work submitted to the system, made up of one or more steps that run in order.
Also written batch job
A job is one piece of batch work, described in JCL and handed to the system to run. It has a name, it runs a sequence of steps, and it finishes with a result you can go and read.
Learn the lifecycle, because the terms come up everywhere. You submit a job. It is queued by the job entry subsystem until resources and priority allow it to run. It executes, step by step. It produces output, which lands on the spool. Then it ends, and its output waits for you in SDSF.
Each job gets a number when it is submitted, and that job number is how you and everyone else refer to that particular run. The same JCL submitted twice produces two jobs with two numbers.
Jobs are the unit of scheduling, of restart and of accounting. When a nightly batch cycle is described as having eight hundred jobs, that is eight hundred of these, wired together in a dependency order by a scheduler.
Related terms
- JCLJob Control Language: the language used to tell the mainframe what programs to run, in what order, and with what files.
- Job stepOne program execution within a job. A job is simply a sequence of steps that run in order.
- SubmitHanding JCL to the system to be run, which queues it as a job and gives it a job number.
- JES2The job entry subsystem: the part of z/OS that queues jobs, decides when they run, and collects their output.
- SpoolThe system-managed holding area where job output waits to be read, printed or purged.
- Return codeA number a program leaves behind saying how it went. Zero for clean, higher numbers for warnings and failures.