Performing background processing which is not on-line or directly connected to the computer for on-line operation. High priority programs take precedence over specific background jobs.

• 指实现后台处理。所谓后台处理是指非联机处理，或者说不是直接和计算机连接起来而进行联机操作。优先级高的程序先于特定的后台作业执行。