The Origin of TCs

Abstract

While a lot of work has been done in real-time systems, in real-time database systems, and more recently, in real-time active databases on the topic of time constrained processing of tasks and transactions, very little work exists that deals with the origin of the time constraints associated with the data, the events, and the actions. In this paper we attempt to identify the sources and semantics of time constraints and show that it is important to minimize the number of “mandated” timing requirements and also weaken the implications of timing constraint violations. The timing properties of interest and also the actions to be taken when the properties are violated can be specified using the Event-Condition-Action rules of active real-time databases. That is, an active real-time database can be made to store the data pertaining to the controlled system as well as the meta-data about the controlling system.