A Survey on the Best Choice for Modulus of Residue Code

Nowadays, the development of technology and the growing need for dense and complex chips have led chip industries to increase their attention on the circuit testability. Also, using the electronic chips in certain industries, such as the space industry, makes the design of fault tolerant circuits a challenging issue. Coding is one of the most suitable methods for error detection and correction. The residue code, as one of the best choices for error detection aims, is wildly used in large arithmetic circuits such as multiplier and also finds a wide range of applications in processors and digital filters. The modulus value in this technique directly effect on the area overhead parameter. A large area overhead is one of the most important disadvantages especially for testing the small circuits. The purpose of this paper is to study and investigate the best choice for residue code check base that is used for simple and small circuits such as a simple ripple carry adder. The performances are evaluated by applying stuck-at-faults and transition-faults by simulators. The efficiency is defined based on fault coverage and normalized area overhead. The results show that the modulus 3 with 95% efficiency provided the best result. Residue code with this modulus for checking a ripple carry adder, in comparison with duplex circuit, 30% improves the efficiency

Concurrent error detection

Concurrent error detection (CED) is the detection of errors or faults in a circuit or data path concurrent with normal operation of that circuit. The general approach for CED is to calculate a check symbol for the inputs to the circuit under operation, predict the check symbol that will result for the output of the circuit for those inputs, and compare the predicted check symbol to the one that is actually calculated for the output. If the predicted and actual check symbols are different, an error or fault has been detected. The alternative to this check symbol prediction is to use a second copy of the circuit under operation and compare the results of the two circuits. For some classes of circuits the prediction of the output check symbol can require less circuitry than a second copy of the circuit being tested. Four examples of these types of circuits are examined in this dissertation: Arithmetic Logic Units (ALUs), array multipliers, self-synchronous scrambler-descrambler pairs with their intervening data path, and switch fabrics. Faults in integrated circuits tend to produce unidirectional errors. Unidirectional errors are those in which all of the errors are in the same direction (e.g., 0 to 1 errors) within the block of data covered by a given check symbol. For this reason, codes that are optimized for unidirectional errors are the focus of investigation for most of the applications. In particular, the Bose-Lin codes are examined for those applications where unidirectional errors are expected to be typical. In order to examine the performance of the Bose-Lin codes in one of these applications, it was necessary to determine the theoretical performance for Bose- Lin codes for error rates beyond what had been previously studied. This analysis of Bose-Lin codes with large numbers of "burst" errors also included a further generalization of the codes

Accelerating Gauss-Newton filters on FPGA's

Includes bibliographical references (leaves 123-128).Radar tracking filters are generally computationally expensive, involving the manipulation of large matrices and deeply nested loops. In addition, they must generally work in real-time to be of any use. The now-common Kalman Filter was developed in the 1960's specifically for the purposes of lowering its computational burden, so that it could be implemented using the limited computational resources of the time. However, with the exponential increases in computing power since then, it is now possible to reconsider more heavy-weight, robust algorithms such as the original nonrecursive Gauss-Newton filter on which the Kalman filter is based. This dissertation investigates the acceleration of such a filter using FPGA technology, making use of custom, reduced-precision number formats

Proceedings of the 22nd Conference on Formal Methods in Computer-Aided Design – FMCAD 2022

The Conference on Formal Methods in Computer-Aided Design (FMCAD) is an annual conference on the theory and applications of formal methods in hardware and system verification. FMCAD provides a leading forum to researchers in academia and industry for presenting and discussing groundbreaking methods, technologies, theoretical results, and tools for reasoning formally about computing systems. FMCAD covers formal aspects of computer-aided system design including verification, specification, synthesis, and testing

Development of an architectural design tool for 3-D VLSI sensors

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 153-159).Three dimensional integration schemes for VLSI have the potential for enabling the development of new high-performance architectures for applications such as focal plane sensors. Due to the high costs involved in 3-D VLSI fabrication and the fabrication complexity of 3-D integration, analysis of the design and process tradeoffs for a particular application is essential. An architectural and topological design tool is presented that enables the high-level analysis and optimization of sensor architectures targeted to a variety of 3-D VLSI process options. This design tool is based on an inference chain evaluation framework, and allows for a high-level structural representation of a circuit architecture to be considered in conjunction with low-level process models. Approximation strategies for projecting circuit area and performance are incorporated into the inference chain relations.by Brian Tyrrell.S.M

Proceedings of the 22nd Conference on Formal Methods in Computer-Aided Design – FMCAD 2022

The Conference on Formal Methods in Computer-Aided Design (FMCAD) is an annual conference on the theory and applications of formal methods in hardware and system verification. FMCAD provides a leading forum to researchers in academia and industry for presenting and discussing groundbreaking methods, technologies, theoretical results, and tools for reasoning formally about computing systems. FMCAD covers formal aspects of computer-aided system design including verification, specification, synthesis, and testing

Proceedings of the 21st Conference on Formal Methods in Computer-Aided Design – FMCAD 2021

The Conference on Formal Methods in Computer-Aided Design (FMCAD) is an annual conference on the theory and applications of formal methods in hardware and system verification. FMCAD provides a leading forum to researchers in academia and industry for presenting and discussing groundbreaking methods, technologies, theoretical results, and tools for reasoning formally about computing systems. FMCAD covers formal aspects of computer-aided system design including verification, specification, synthesis, and testing

Low-cost and efficient fault detection and diagnosis schemes for modern cores

Continuous improvements in transistor scaling together with microarchitectural advances have made possible the widespread adoption of high-performance processors across all market segments. However, the growing reliability threats induced by technology scaling and by the complexity of designs are challenging the production of cheap yet robust systems. Soft error trends are haunting, especially for combinational logic, and parity and ECC codes are therefore becoming insufficient as combinational logic turns into the dominant source of soft errors. Furthermore, experts are warning about the need to also address intermittent and permanent faults during processor runtime, as increasing temperatures and device variations will accelerate inherent aging phenomena. These challenges specially threaten the commodity segments, which impose requirements that existing fault tolerance mechanisms cannot offer. Current techniques based on redundant execution were devised in a time when high penalties were assumed for the sake of high reliability levels. Novel light-weight techniques are therefore needed to enable fault protection in the mass market segments. The complexity of designs is making post-silicon validation extremely expensive. Validation costs exceed design costs, and the number of discovered bugs is growing, both during validation and once products hit the market. Fault localization and diagnosis are the biggest bottlenecks, magnified by huge detection latencies, limited internal observability, and costly server farms to generate test outputs. This thesis explores two directions to address some of the critical challenges introduced by unreliable technologies and by the limitations of current validation approaches. We first explore mechanisms for comprehensively detecting multiple sources of failures in modern processors during their lifetime (including transient, intermittent, permanent and also design bugs). Our solutions embrace a paradigm where fault tolerance is built based on exploiting high-level microarchitectural invariants that are reusable across designs, rather than relying on re-execution or ad-hoc block-level protection. To do so, we decompose the basic functionalities of processors into high-level tasks and propose three novel runtime verification solutions that combined enable global error detection: a computation/register dataflow checker, a memory dataflow checker, and a control flow checker. The techniques use the concept of end-to-end signatures and allow designers to adjust the fault coverage to their needs, by trading-off area, power and performance. Our fault injection studies reveal that our methods provide high coverage levels while causing significantly lower performance, power and area costs than existing techniques. Then, this thesis extends the applicability of the proposed error detection schemes to the validation phases. We present a fault localization and diagnosis solution for the memory dataflow by combining our error detection mechanism, a new low-cost logging mechanism and a diagnosis program. Selected internal activity is continuously traced and kept in a memory-resident log whose capacity can be expanded to suite validation needs. The solution can catch undiscovered bugs, reducing the dependence on simulation farms that compute golden outputs. Upon error detection, the diagnosis algorithm analyzes the log to automatically locate the bug, and also to determine its root cause. Our evaluations show that very high localization coverage and diagnosis accuracy can be obtained at very low performance and area costs. The net result is a simplification of current debugging practices, which are extremely manual, time consuming and cumbersome. Altogether, the integrated solutions proposed in this thesis capacitate the industry to deliver more reliable and correct processors as technology evolves into more complex designs and more vulnerable transistors.El continuo escalado de los transistores junto con los avances microarquitectónicos han posibilitado la presencia de potentes procesadores en todos los segmentos de mercado. Sin embargo, varios problemas de fiabilidad están desafiando la producción de sistemas robustos. Las predicciones de "soft errors" son inquietantes, especialmente para la lógica combinacional: soluciones como ECC o paridad se están volviendo insuficientes a medida que dicha lógica se convierte en la fuente predominante de soft errors. Además, los expertos están alertando acerca de la necesidad de detectar otras fuentes de fallos (causantes de errores permanentes e intermitentes) durante el tiempo de vida de los procesadores. Los segmentos "commodity" son los más vulnerables, ya que imponen unos requisitos que las técnicas actuales de fiabilidad no ofrecen. Estas soluciones (generalmente basadas en re-ejecución) fueron ideadas en un tiempo en el que con tal de alcanzar altos nivel de fiabilidad se asumían grandes costes. Son por tanto necesarias nuevas técnicas que permitan la protección contra fallos en los segmentos más populares. La complejidad de los diseños está encareciendo la validación "post-silicon". Su coste excede el de diseño, y el número de errores descubiertos está aumentando durante la validación y ya en manos de los clientes. La localización y el diagnóstico de errores son los mayores problemas, empeorados por las altas latencias en la manifestación de errores, por la poca observabilidad interna y por el coste de generar las señales esperadas. Esta tesis explora dos direcciones para tratar algunos de los retos causados por la creciente vulnerabilidad hardware y por las limitaciones de los enfoques de validación. Primero exploramos mecanismos para detectar múltiples fuentes de fallos durante el tiempo de vida de los procesadores (errores transitorios, intermitentes, permanentes y de diseño). Nuestras soluciones son de un paradigma donde la fiabilidad se construye explotando invariantes microarquitectónicos genéricos, en lugar de basarse en re-ejecución o en protección ad-hoc. Para ello descomponemos las funcionalidades básicas de un procesador y proponemos tres soluciones de `runtime verification' que combinadas permiten una detección de errores a nivel global. Estas tres soluciones son: un verificador de flujo de datos de registro y de computación, un verificador de flujo de datos de memoria y un verificador de flujo de control. Nuestras técnicas usan el concepto de firmas y permiten a los diseñadores ajustar los niveles de protección a sus necesidades, mediante compensaciones en área, consumo energético y rendimiento. Nuestros estudios de inyección de errores revelan que los métodos propuestos obtienen altos niveles de protección, a la vez que causan menos costes que las soluciones existentes. A continuación, esta tesis explora la aplicabilidad de estos esquemas a las fases de validación. Proponemos una solución de localización y diagnóstico de errores para el flujo de datos de memoria que combina nuestro mecanismo de detección de errores, junto con un mecanismo de logging de bajo coste y un programa de diagnóstico. Cierta actividad interna es continuamente registrada en una zona de memoria cuya capacidad puede ser expandida para satisfacer las necesidades de validación. La solución permite descubrir bugs, reduciendo la necesidad de calcular los resultados esperados. Al detectar un error, el algoritmo de diagnóstico analiza el registro para automáticamente localizar el bug y determinar su causa. Nuestros estudios muestran un alto grado de localización y de precisión de diagnóstico a un coste muy bajo de rendimiento y área. El resultado es una simplificación de las prácticas actuales de depuración, que son enormemente manuales, incómodas y largas. En conjunto, las soluciones de esta tesis capacitan a la industria a producir procesadores más fiables, a medida que la tecnología evoluciona hacia diseños más complejos y más vulnerables

Berger Check Prediction for Array Multipliers and Array Dividers

In this correspondence, we present close form check predicting equations to derive Berger checks for array multipliers and array dividers, respectively. Braun’s array multipliers and Guild’s array dividers are examined. Example check circuits are also presented. © 1993 IEE

The 1982 NASA/ASEE Summer Faculty Fellowship Program

A NASA/ASEE Summer Faculty Fellowship Research Program was conducted to further the professional knowledge of qualified engineering and science faculty members, to stimulate an exchange of ideas between participants and NASA, to enrich and refresh the research and teaching activities of participants' institutions, and to contribute to the research objectives of the NASA Centers