Batch scheduler
Software that submits production jobs automatically in the right order, at the right time, based on what has already succeeded.
Also written job scheduler, workload scheduler, CA-7
Production batch is not submitted by hand. A scheduler holds the definition of what runs, when, and in what order, and drives the whole nightly cycle automatically.
The core of it is dependencies. A job that produces a file must finish successfully before the job that reads it starts. Multiply that by hundreds of jobs and you have a dependency network that no person could run manually at three in the morning.
Schedulers also handle calendars, so month-end and year-end work runs only when it should; time constraints, so a job waits for a file from another organisation; and failure handling, so an operator is alerted and the dependent work holds rather than running on bad data.
Common products include IBM Workload Scheduler and CA-7, and most sites have one of a handful.
The JCL you write is only half the picture. In production it is the scheduler that decides when your job runs and what happens if it fails.
Related terms
- Batch windowThe period, usually overnight, in which batch work has to finish before the business needs the systems back.
- JobA unit of batch work submitted to the system, made up of one or more steps that run in order.
- Batch processingRunning work in bulk, without anyone watching, usually on a schedule. The overnight run that settles a day of transactions.
- OperatorThe person who watches the running systems, responds to messages, and starts, stops and recovers work.
- Return codeA number a program leaves behind saying how it went. Zero for clean, higher numbers for warnings and failures.
- Production supportKeeping live systems running: diagnosing failures, fixing what broke, and getting the service back.
- Generation data groupA set of datasets holding successive versions of the same file, so today's copy, yesterday's and last week's all exist under one name.