Low-cost coding techniques for digital fault diagnosis

Published report discusses fault location properties of arithmetic codes. Criterion for effectiveness of given code is detection probability of local fault by application of checking algorithm to results of entire set of algorithms of processor. Report also presents analysis of arithmetic codes with low-cost check algorithm which possesses partial fault-location properties

Self-testing and repairing computer Patent

Self testing and repairing computer comprising control and diagnostic unit and rollback points for error correctio

Self testing and repairing computer - A concept

STAR computer has five redundant modular function units, fixed store, arithmetic, memory, input, and output. Each unit is connected to a diagnostic control unit, each is coded for error detection and error correction. Separation into function units permits assembly of many different systems from the set of units

Design methods for fault-tolerant navigation computers

Design methods for fault tolerant navigation computer

Fault-tolerant computer study

A set of building block circuits is described which can be used with commercially available microprocessors and memories to implement fault tolerant distributed computer systems. Each building block circuit is intended for VLSI implementation as a single chip. Several building blocks and associated processor and memory chips form a self checking computer module with self contained input output and interfaces to redundant communications buses. Fault tolerance is achieved by connecting self checking computer modules into a redundant network in which backup buses and computer modules are provided to circumvent failures. The requirements and design methodology which led to the definition of the building block circuits are discussed

Design of fault-tolerant computers

Causes and symptoms of logic faults in digital systems. Reliable performance of hardware has been a require-ment for digital systems since the construction of the first digital computer. Improper functioning of the logic circuits in a digital system is manifested by logic faults, which are defined for this paper as "permanent or transient deviations of logic variables from the values specified in design." Permanent faults are caused by physical changes in the components of a logic circuit which permanently alter the logic function specified by the designer. The most common permanent faults are the determinate faults of "stuck on zero " and "stuck on one " types. Less frequent is the indeterminate or "stuck on X " fault

Algorithm Diversity for Resilient Systems

Diversity can significantly increase the resilience of systems, by reducing the prevalence of shared vulnerabilities and making vulnerabilities harder to exploit. Work on software diversity for security typically creates variants of a program using low-level code transformations. This paper is the first to study algorithm diversity for resilience. We first describe how a method based on high-level invariants and systematic incrementalization can be used to create algorithm variants. Executing multiple variants in parallel and comparing their outputs provides greater resilience than executing one variant. To prevent different parallel schedules from causing variants' behaviors to diverge, we present a synchronized execution algorithm for DistAlgo, an extension of Python for high-level, precise, executable specifications of distributed algorithms. We propose static and dynamic metrics for measuring diversity. An experimental evaluation of algorithm diversity combined with implementation-level diversity for several sequential algorithms and distributed algorithms shows the benefits of algorithm diversity

Diversity and Adjudication

This paper takes an axiomatic and calculational view of diversity (or "N-version programming"), where multiple implementations of the same specification are executed in parallel to increase dependability. The central notion is "adjudication": once we have multiple, potential different, outcomes, how do we come to a single result? Adjudication operators are explicitly defined and some general properties for these explored