In a batch processing computer system, a job stream, jobstream, or simply job is the sequence of job control language statements (JCL) and data (called instream data) that comprise a single "unit of work for an operating system". A job consists of the execution of one or more programs. 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.