Initiator
An address space that runs batch jobs one at a time, taking each new job from the queue for the job classes it serves.
Also written INIT, batch initiator, WLM-managed initiator
An initiator is what actually runs a batch job. It is an address space that waits for work, takes a job from the JES queue, runs its steps one after another, and then takes the next job.
Each initiator serves a list of job classes. An initiator set up for classes A and B will only pick up jobs in those classes. If you submit a job in class C and no initiator serves class C, the job waits in the queue and never starts, which is a common surprise for beginners.
The number of initiators limits how many batch jobs can run at the same time. Operators can start, stop and change initiators with JES2 commands. Many sites let WLM manage the initiators for some job classes, starting more when there is a lot of work waiting and fewer when the system is busy with more important work.
If your job shows as waiting and not running, check its class, then check whether any initiator is serving that class and whether they are all busy.
Where can I learn this hands-on?
Right here, at ZedBank. You take a junior job at a simulated bank and learn each part of the work by doing it, with Zed beside you. There's nothing to install.
Start at ZedBankRelated
- Job classA single-character label on a job that tells the system what kind of work it is and how to schedule it.
- JES2The job entry subsystem: the part of z/OS that queues jobs, decides when they run, and collects their output.
- JobA unit of batch work submitted to the system, made up of one or more steps that run in order.
- Address spaceAn isolated pocket of memory in which a program runs, so that one program cannot interfere with another.
- WLMWorkload Manager: the part of z/OS that decides which work gets the processor, memory and disk access first, based on goals the site sets.
- Batch processingRunning work in bulk, without anyone watching, usually on a schedule. The overnight run that settles a day of transactions.