ABSTRACT
Reliability of a system is the probability that the system will perform a certain operating function under given conditions for a given period of time. The reliability of a computer-based control system can be attained either by the use of a smaller number of highly-reliable, single-computers, or by implementing a redundant, multi-computer system, built out of a higher number of less reliable individual computers. In a multi-computer system, not only the failure of a computer can cause the malfunctioning of the total system, but also the failure of its peripherals. Computer software receives inputs from the environmental facilities, processes them, and outputs the results to the environment. Operating system must constantly monitor the program execution in order to avoid the computer time or the resource time overload. Distributed computer control systems, being real-time systems for solving also time-critical automation problems, have an additional reliability aspect.
