Browsing by Author "Bidulock, D.S."

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    The design and simulation of a multi-computer network message processor
    (1981-02-01) Unger, Brian W; Bidulock, D.S.
    This paper describes a simulation language and its application to the design of a multicomputer network message processor. The language, called OASIS, provides a programming environment which facilitates the development of distributed software. Modular software, computer system hardware models, and the simulated execution of this software by the hardware models can be defined within OASIS. The network message processor supports bidirectional data transmission among terminals, host computers, and other network message processors. A modular design of this network message processor is implemented by a local network of five microcomputers communicating over a time shared bus. In this paper, OASIS is used to develop system software before network message processor hardware is available.
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    Modular design of multicomputer systems
    (1981-03-01) Unger, Brian W; Bidulock, D.S.
    Multicomputer systems involve complex hardware and software components and extensive interaction among these components. Furthermore, rapid advances in semiconductor chip technology result in many possible implementations for a given system requirement. The relative merits of different possible hardware implementations are difficult to determine at an early stage of design and will often subsequently change. Thus a need exists for design methods that enable delaying implementation decisions as long as possible. System structure, that is, the definition of major components and their interaction is often not dependent on the physical implementation. The structural design of a system, however largely determines important system characteristics such as performance, modularity, reliability, visibility, and adaptability. We outline a system structural design method based on guidelines that promote modularity and access graphs that specify component interactions. This method is then applied to a typical example, the design of a network message processor. This processor provides communication in a network of multiple computers and interactive terminals.
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    A modular operating system for network message processor
    (1978-02-01) Unger, Brian W; Bidulock, D.S.
    This paper describes the design of a modular operating system for a network message processor. The basic requirements of the message processor are defined by the University of Calgary's Distributed Communication System (DCS), which is a general purpose network connecting a variety of interactive terminals, two host computers, and a trans-Canada network (DATPAC). Starting with these requirements, the operating system is decomposed into a small set of easily understood components whose interactions are both restricted and simple. A brief outline is then presented of the implementation of these components in Oasis, an extension of Simula 67 which was designed for implementing and simulating system software. Finally, it is conjectured that: (1) A new, more flexible, reliable system can be easily developed from this Oasis version, and (2) the effort required to implement and test both the Oasis simulated version and the actual system will be much less than that required for the original operating system development.