A language for describing jobs (units of work) to the OS/390, z/ OS, and VSE operating systems, which run on IBM's OS/390 and z800/900 large server (mainframe) computers. These operating systems allocate time and space resources among the total number of active jobs. Jobs in turn break down into job steps, which are the statements required to run a particular program. Jobs are background (sometimes called batch) units of work that run without requiring user interaction (for example, print jobs). In addition, the operating system manages interactive (foreground) user requests that initiate units of work. In general, foreground work is given priority over background work.