Attributes of a real-time embedded system

The hardware and software of a real-time embedded system must exhibit some specific characteristics to ensure the system reliably meets its performance goals of producing reliably correct and timely outputs. Most real-time embedded systems that perform functions of moderate to high complexity must divide the processing work into multiple tasks that execute in an apparently (to the user) simultaneous manner, including managing the operation of hardware such as an automobile engine while regularly updating information displayed to the driver.

At the finest-grained level of processor operation, most embedded systems rely on the use of interrupts to notify the processor when an operation is required by an I/O device. In a real-time application, the handling of interrupts can become a critical factor in ensuring proper system operation. At the simplest level, any time an interrupt is being processed, the code algorithm that was paused to handle...