Robert W. Horst

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This paper examines the problems of deadlock avoidance in multistage networks, and proposes a new class of scalable topologies for constructing large networks without introducing loops that could cause deadlocks. The new topologies, called “fractahedrons,” are deadlock-free and reduce the maximum link contention compared to other networks. The use of(More)
A major departure from traditional VO systems, TNet is a new system area network designed to s"pp0rt current and future needs for reliable, efficient communications among processors and peripherals. It is an extensible hardware-software layer that allows very large configurations by logically and physically isolating processor buses from VO buses. TNet(More)
This paper describes the architecture for issuing multiple instructions per clock in the NonStop Cyclone Processor. Pairs of instructions are fetched and decoded by a dual two-stage prefetch pipeline and passed to a dual six-stage pipeline for execution. Dynamic branch prediction is used to reduce branch penalties. A unique microcode routine for each pair(More)
  • Robert W Horst
  • Conference proceedings : ... Annual International…
  • 2009
This paper describes a wearable powered leg orthosis that includes a high-torque actuator, electronics, sensors, and embedded firmware. The device provides multiple modes of operation including automatic assistance, manual assistance, continuous passive motion and robotic therapy. Patients affected by neurological conditions including stroke, MS, and(More)
Most microprocessor-based systems provide little or no checking for failures of the microprocessor itself. These systems rely on the high reliability of VLSI and the inherent run-time checks (e.g., virtual memory protection and illegal instruction exceptions) to ensure data integrity. The authors present a model for analyzing the vulnerability of systems to(More)
This paper describes a performance analysis of ServerNet SAN, a new system area network architecture developed by Tandem Computers. The paper focuses on three main topics: a brief description of the ServerNet SAN architecture and the simulation tool, the basis for modeling assumptions, and the initial results of the performance and scalability analysis. The(More)
Self-similar traffic distributions have been observed in a wide range of networking applications and models such as LANs, WANs, telnet, FTP, WWW, ISDN, SS7 and VBR traffic over ATM. Therefore, it has been suggested that many other theoretical protocols and systems need to be reevaluated under this different type of traffic before practical implementations(More)
This paper presents several different ways of designing systems with ServerNet-connected I/O devices. The ServerNet System Area Network is a multistage, wormholerouted network designed for reliable I/O and inter-processor communications. Designing a SAN to be used both for I/O and IPC has benefits in system cost and flexible expansion, but requires a(More)