In a production environment, multiple tasks are taking place simultaneously. You need a scheduler to determine which action is given priority and which one has to wait. The design of realtime software has to guarantee determinism. This may also be regarded as predictability. This is programming which determines the task that takes preference. Failure to have a reasonable order leads to negative out comes. There is a deadline element to every RTS. During programming, the system must respond to a command within a set time frame. Missing this deadline may be catastrophic, like in the case of an airbag deploying, or may simply bring undesired results, like in production where the quality of a product is reduced.