Towards developing of Oberon system with specific requirements of ergodicity

The ergodic system keeps the time average is the same for almost all initial points. It is important for computer systems to prevent the degradation of the properties of the system over time. Ergodicity is especially required for mission-critical systems in demanding industries. Software development based on the functional safety requirements of the IEC 60880 category A standard is implemented only on newly created software that meets the most stringent requirements for nuclear power plants, it is impossible to use standard operating systems and compilers. For these purposes, a prototype of the runtime environment and application software of the command display system (DSCU) was implemented. The runtime was created based on the Active Oberon A2 system. A2 is a single-user multi-tasking system. Application area - industrial embedded real-time systems, high reliability systems. The DSKU execution environment is implemented by a significant revision of the minimum subset A2 to meet the requirements of the standard. The system of restrictions formed according to the requirements of the standard makes it possible to create computer systems with new properties. The use of these constraints leads to the proof that there is no possibility of the occurrence of the failures they cause and allows us to consider a computer system based on the presumption of non-ergodicity. This «via negative» approach is based on restrictions, the addition of which allows one to obtain new qualitative properties. The more restrictions, the greater the gain in system reliability and stability.