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Although building systems from components has attractions, this approach also has problems. Can we be sure that a certain configuration of components is correct? Can it perform as well as a monolithic system? Our paper answers these questions for the Ensemble communication architecture by showing how, with help of the Nuprl formal system, configurations may(More)
Ensemble is a widely used group communication system that supports distributed programming by providing precise guarantees for synchronization, message ordering, and message delivery. Ensemble eases the task of distributed-application programming, but as a result, ensuring the correctness of Ensemble itself is a diicult problem. In this paper we use I/O(More)
– The Horus and Ensemble efforts culminated a multi-year Cornell research program in process group communication used for fault-tolerance, security and adaptation. Our intent was to understand the degree to which a single system could offer flexibility and yet maintain high performance, to explore the integration of fault-tolerance with security and(More)
MetaPRL is the latest system to come out of over twenty five years of research by the Cornell PRL group. While initially created at Cornell, MetaPRL is currently a collaborative project involving several universities in several countries. The MetaPRL system combines the properties of an interactive LCF-style tactic-based proof assistant, a logical(More)
Theorem proving techniques are particularly well suited for reasoning about arithmetic above the bit level and for relating diierent levels of abstraction. In this paper we show h o w a non-restoring integer square root algorithm can be transformed to a very eecient hardware implementation. The top level is a Standard ML function that operates on unbounded(More)
Higher-order logics are expressive tools for tasks ranging from formalizing the foundations of mathematics to large-scale software veriication and synthesis. Because of their complexity, proofs in higher-order logics often use a combination of interactive proving together with computationally-intensive tactic applications that perform proof automation. As(More)
We present a theorem proving environment for the development of reliable and efficient group communication systems. Our approach makes methods of automated deduction applicable to the implementation of real-world systems by linking the Ensemble group communication toolkit to the NuPRL proof development system. We present tools for importing Ensemble's code(More)