ECCO: Data Centric Asynchronous Communication. Challenges for event and query modelling and asynchronous message passing

Guideline 1a: Identify Active Devices Active input or output I/O devices use interrupts to communicate with real-time applications. Every time an active input device needs to send data or notification of an event to a real-time application, the device generates an interrupt. The interrupt triggers an ISR that executes the minimum code needed to handle the input. If a lot of processing is required, the ISR usually hands off the process to an associated task through an inter-task communication mechanism. Similarly, active output devices also generate interrupts when they need to communicate with applications. However, interrupts from active output devices are generated when they are ready to receive the next piece of data or notification of some event from the application. The interrupts trigger the appropriate ISR that hands off the required processing to an associated task using an inter-task communication mechanism. The diagram for both an active I/O device acting as an input or an output to an application and for a device generating interrupts in a synchronous or asynchronous manner is similar to the one illustrated in Figure 14.5. Figure 14.5: General communication mechanisms for active I/O devices ...»