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The paper discusses a model of an automated system for sorting correspondence, developed in the VisSim environment. A simulation model of information coding has been developed. The possibility of optimizing the operation of similar lines is shown. A generalized algorithm for managing the sorting and accumulation of correspondence has been developed.

Nested Rollout Policy Adaptation (NRPA) is a Monte Carlo search algorithm for single player games. In this paper we propose to generalize NRPA with a temperature and a bias and to analyze theoretically the algorithms. The generalized algorithm is named GNRPA. Experiments show it improves on NRPA for different application domains: SameGame and the Traveling Salesman Problem with Time Windows.

In previous chapters, we introduced the three main processes required to implement generalized algorithm of fault tolerance (GAFT), namely—testing and checking, second recovery preparation, and third and finally recovery and recovery monitoring. We described what every of these steps incorporates, gave possible solutions, and analyzed them. In the Chap. 7, we introduced syndrome for testing and checking; here we introduce programming language models for the two other mentioned processes. What we now want to do is to synthesize the introduced concepts into system software tools—programming languages and their compilers. We will discuss possible project solutions related to the overall architecture of software tools and introduce the major components of the architecture.

In previous chapters we introduced the processes of checking and testing, the first of the three main processes of generalized algorithm of fault tolerance—GAFT. In this chapter we further discuss the process of checking hardware, at first software-based hardware checking and at second hardware-based checking. For the software-based hardware checking, we show what a software-based test should include, when they are the preferred choice over hardware-based checking schemes and especially how such tests can be scheduled in the system without interfering with ongoing real-time tasks. Further to support handling of hardware -based checking we introduce a new system condition descriptor—a so-called syndrome—and illustrate how it can be used as a mechanism to signal to the operating system hardware condition, including manifestation of detected error. We then show the steps the run-time system performs to eliminate the fault and in case of permanent errors how the software can reconfigure the hardware to exclude the faulty element. We also explain in which cases software has to adapt to the new hardware topology. We start by explaining how software-based checks can be used to detect hardware faults. Run-time systems use online or off-line scheduling mechanisms for task management of programs—own—system software ones and user application ones. Since in Kirby et al. (Softw Pract Exp 15(1):87–103, 1985, [2]), Serlin (Comput C 7(8):19–30, 1984, [3]), Blazewicz et al. (Handbook on scheduling, from theory to applications, 2007, [4]), Ingo (Linux kernel archive, 2002, [8]) it is expected that run-time system provides a special session of task scheduling (off-line or online during execution) for the purposes of diagnostic of hardware conditions—recall Apple and Microsoft system starting delays. Later for some systems that operate in domain of real-time monitoring scheduling of tasks, critical in time of execution especially criticality of hardware availability and efficiency of process scheduling, become crucial. In turn testing itself become “hot” in terms of required time and coverage of hardware. Thus in this chapter we initially analyze simple sequences of testing of hardware elements of computer systems. Further, we introduce a concept of transparent for user application procedure of hardware testing. This enables to prove the integrity of computer system hardware, and guarantee it within reasonable time, without delays of service of execution of user tasks.

Fault tolerance so far was considered as a property of a system. In fact and instead we introduce a generalized algorithm of fault tolerance (GAFT) that considers property of fault tolerance as a system process. GAFT implementation analysis—if we want to make it rigorous—should be using classification of redundancy types. Various redundancy types have different “power” of use at various steps of GAFT. Properties of GAFT implementation impact on overall performance of the system, coverage of faults , and ability of reconfiguration. It is clear that separation of malfunctions from permanent fault simply must be implemented and reliability gain is analyzed. A ratio of malfunctions to permanent faults is achieving 105–7 and simple exclusion from working configuration a malfunctioned element is not longer feasible. Further, we have to consider GAFT extension in terms of generalization and application for support of system safety of complex systems. Our algorithms of searching correct state, “guilty” element, and analysis of potential damages become powerful extension of GAFT for challenging applications like avionic systems, aircraft as a whole. In Chap. 3, we showed that fault tolerance should be treated as a process . In this chapter, we elaborate further this process into a clearly defined algorithm and develop a framework to the design of fault-tolerant systems, the generalized algorithm of fault tolerance—GAFT. We also introduce a theoretical model to quantify the impact of the additional redundancy to the reliability of the whole system and derive an answer to the question of how much added redundancy leads to the system with highest reliability. A question that GAFT cannot answer is how the real source of a detected fault can be identified, as the fault manifestation might have occurred in another hardware element and spread in the system due to nonexistent fault containment. We will show an algorithm that based on the dependencies of the elements of a system can identify the possible fault sources and also predict which elements an identified fault might have affected. We now start in a first step by further elaborating the process of fault tolerance .

Fault tolerance so far was considered as a property of a system. In fact and instead we introduce a generalized algorithm of fault tolerance (GAFT) that considers fault tolerance as a system process. There is no doubt we have to analyze GAFT implementation using redundancy types of computer systems. Properties of GAFT implementation impact on overall performance of the system, coverage of faults, and ability of reconfiguration. It is clear that separation of malfunctions from permanent fault simply must be implemented and reliability gain is analyzed. A ratio of malfunctions to permanent faults is achieving 105−7 and simple exclusion from working configuration of a malfunctioned element is no longer feasible. In this chapter, we consider GAFT extension in terms of generalization and application for support of system safety of complex systems. Our algorithms of searching correct state, “guilty” element, and analysis of potential damages become powerful extension of GAFT for challenging applications like avionic systems, aircraft as a whole.