Real-Time procedures in distributed systems

Abstract

This chapter discusses the various real-time software design methodologies. The real-time software poses various problems for the designer such as representation of interrupts and context switching, asynchronous processing, intertask communication and synchronization, and wide variations in data and communication rates. The design of the real-time software requires the incorporation of the fundamental concepts associated with high-quality software such as abstraction and modularity. Some design methods extend one of the three classes of design: data flow, data structure, or object-oriented methodologies. The dataflow-oriented design methods are the most widely used in the industry. Dataflow models are used to show how the data flows through a sequence of processing steps. The data is transformed at each step before moving on to the next stage. Design method for real-time systems (DARTS) is an extension that allows the real-time system designers to adapt the dataflow techniques to the special needs of the real-time applications. Another approach to the design of the real-time systems is the use of the real-time procedures that include timing constraints. These procedures can be organized with a dataflow-oriented method based on simple data streams.