System issues in embedded control

The computer in an embedded computer system is not used for manipulation of data as an end in itself but for the control of physical devices or processes. The problems associated with the control of a large and complex system composed of coupled subsystems are examined. Often, a real-time component of the required processing demands system response within a characteristic time determined by the system being controlled. The standards of reliability, survivability, and correctness which must be met by the computer system hardware and software are different. The control must function and not display any chaotic instabilities. The design must be such that it is self-stabilizing in the presence of both software and hardware errors. Because the system is distributed, there is the problem of maintaining consistency among multiple copies of the same information resident in different processors. The system can be structured to use more relaxed updating approaches as a tradeoff for improved performance.<>