Job stream

In a <a href="/facts/Non-interactive/9LeFR3ru">non-interactive</a> computer system, particularly <a href="/facts/IBM/QszA7nwd">IBM</a> <a href="/facts/Mainframe/nrBR6rWa">mainframes</a>, a job stream, jobstream, or simply <a href="/facts/Job_(computing)/pW4LEz0Q">job</a> is the sequence of <a href="/facts/Job_control_language/UCpfhoe4">job control language</a> statements (JCL) and data (called instream data) that comprise a single "unit of work for an operating system". The term job traditionally means a one-off piece of work, and is contrasted with a batch (executing the same steps over many inputs), but non-interactive computation has come to be called "<a href="/facts/Batch_processing/hKY2rX3N">batch processing</a>", and thus a unit of batch processing is often called a job, or by the oxymoronic term <a href="/facts/Batch_job/hKY2rX3N">batch job</a>; see <a href="/facts/Job_(computing)/pW4LEz0Q">job</a> for details. Performing a job consists of <a href="/facts/Execution_(computing)/1fyfGMFm">executing</a> one or more <a href="/facts/Computer_program/e38jH9N9">programs</a>. Each program execution, called a job step, jobstep, or step, is usually related in some way to the others in the job. Steps in a job are executed sequentially, possibly depending on the results of previous steps, particularly in batch processing.
The term "job stream" is particularly associated with mainframes; in the <a href="/facts/IBM/QszA7nwd">IBM</a> <a href="/facts/Z%2fOS/amLCAlgV">z/OS</a> operating system, a job is initiated by a // JOB and terminated by the next // JOB or // statement. Each job step consists of one // EXEC statement indicating the program to be executed and usually multiple // DD statements defining the <a href="/facts/Computer_file/FjFH3Ufm">files</a> and devices to be used.

Job stream open-in-new

Job stream