785 research outputs found
Emulating Digital Logic using Transputer Networks (Very High Parallelism = Simplicity = Performance)
Modern VLSI technology has changed the economic rules by which the balance between processing
power, memory and communications is decided in computing systems. This will have a profound
impact on the design rules for the controlling software. In particular, the criteria for judging efficiency
of the algorithms will be somewhat different. This paper explores some of these implications through
the development of highly parallel and highly distributable algorithms based on occam and transputer
networks. The major results reported are a new simplicity for software designs, a corresponding ability
to reason (formally and informally) about their properties, the reusability of their components and some
real performance figures which demonstrate their practicality. Some guidelines to assist in these designs
are also given. As a vehicle for discussion, an interactive simulator is developed for checking the
functional and timing characteristics of digital logic circuits of arbitrary complexity
Structural dynamics branch research and accomplishments for fiscal year 1987
This publication contains a collection of fiscal year 1987 research highlights from the Structural Dynamics Branch at NASA Lewis Research Center. Highlights from the branch's four major work areas, Aeroelasticity, Vibration Control, Dynamic Systems, and Computational Structural Methods, are included in the report as well as a complete listing of the FY87 branch publications
Implementing tuple space on transputer meshes
Research Report submitted to the Faculty of Science, University of the Witwatersrand,
Johannesburg, towards a partial fulfilment of the requirements for the degree
of Master of Science
Johannesburg 1991This report describes and evaluates an implementation of the Linda tuple space abstraction
on Transputer networks. There is evidence that suggests a need for a new
programming methodology to support Transputer-based applications, and Linda, as
an attractive and elegant alternative to existing methodologies, has great potential
for this role. The research focuses on the implementation of a particular tuple space
model, intermediate uniform distribution, on Transputer meshes. The objective of
the research is to ascertain the extent of the communication overheads inherent in
the implementation and hence evaluate the feasibility of the approach. The overheads
are measured relative to message passing performance on native Transputer
networks, and are shown to be significant. It is concluded that although the specific
tuple space model is not ideally suited to Transputer-based systems and the implementation,
as it stands, is too inefficient to be of practical use, the approach requires
further exploration in order to exhaust its full research potential.MT201
Network control for a multi-user transputer-based system.
A dissertation submitted to the Faculty of Engineering, University of the
Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of
Master of Science in EngineeringThe MC2/64 system is a configureable multi-user transputer- based system which was
designed using a modular approach. The MC2/64 consists of MC2 Clusters which are
connected using a modified Clos network. The MC2 Clusters were designed and
realised as completely configurable modules using and extending an algorithm based on
Eulerian cycles through a requested graph. This dissertation discusses the configuration
algorithm and the extensions made to the algorithm for the MC2 Clusters.
The total MC2/64 system is not completely configurable as a MC2 Cluster releases only
a limited number of links for inter-cluster connections. This dissertation analyses the
configurability of MC2/64, but also presents algorithms which enhance the usability of
the system from the user's point of view.
The design and the implementation of the network control software are also submitted
as topics in this dissertation. The network control software must allow multiple users to
use the system, but without them influencing each other's transputer domains.
This dissertation therefore seeks to give an overview of network control problems and
the solutions implemented in current MC2/64 systems. The results of the research
done for this dissertation will hopefully aid in the design of future MC2 systems which
will provide South Africa with much needed, low cost, high performance computing
power.Andrew Chakane 201
Parallel process placement
This thesis investigates methods of automatic allocation of processes to available processors in a given network configuration. The research described covers the investigation of various algorithms for optimal process allocation. Among those researched were an algorithm which used a branch and bound technique, an algorithm based on graph theory, and an heuristic algorithm involving cluster analysis. These have been implemented and tested in conjunction with the gathering of performance statistics during program execution, for use in improving subsequent allocations. The system has been implemented on a network of loosely-coupled microcomputers using multi-port serial communication links to simulate a transputer network. The concurrent programming language occam has been implemented, replacing the explicit process allocation constructs with an automatic placement algorithm. This enables the source code to be completely separated from hardware consideration
Distributed Finite Element Analysis Using a Transputer Network
The principal objective of this research effort was to demonstrate the extraordinarily cost effective acceleration of finite element structural analysis problems using a transputer-based parallel processing network. This objective was accomplished in the form of a commercially viable parallel processing workstation. The workstation is a desktop size, low-maintenance computing unit capable of supercomputer performance yet costs two orders of magnitude less. To achieve the principal research objective, a transputer based structural analysis workstation termed XPFEM was implemented with linear static structural analysis capabilities resembling commercially available NASTRAN. Finite element model files, generated using the on-line preprocessing module or external preprocessing packages, are downloaded to a network of 32 transputers for accelerated solution. The system currently executes at about one third Cray X-MP24 speed but additional acceleration appears likely. For the NASA selected demonstration problem of a Space Shuttle main engine turbine blade model with about 1500 nodes and 4500 independent degrees of freedom, the Cray X-MP24 required 23.9 seconds to obtain a solution while the transputer network, operated from an IBM PC-AT compatible host computer, required 71.7 seconds. Consequently, the 15,000,000 Cray X-MP24 system
The Hamlet design entry system: an overview of ADL and its environment
Exploiting parallelism for industrial real-time applications has not received much attention compared to scientific applications. The available real-time design methods do not adequately address the issue of parallelism, resulting still in a strong need for low-level tools such as debuggers and monitors. This need illustrates that developing parallel real-time applications is indeed a difficult and tedious task. In this paper we show how problems can be alleviated if an approach is followed that allows for experimentation with designs and implementations. In particular, we discuss a development system that integrates design, implementation, execution, and analysis of real-time applications, putting emphasis on exploitation of parallelism. In the paper we primarily concentrate on the support for application *design*, as we feel that parallelism should essentially be addressed at this level
An empirical evaluation of techniques for parallel simulation of message passing networks
209 p.[EN]In the field of computer design, simulation is an essential tool to validate and evaluate architectural proposals. Conventional simulation techniques, designed for their use in sequential computers, are too slow if the system to simulate is large or complex. The aim of this work is to search for techniques to accelerate simulations exploiting the parallelism available in current, commercial multicomputers, and to use these techniques to study a model of a message router. This router has been designed to constitute the communication infrastructure of a (hypothetical) massively parallel computer.
Three parallel simulation techniques have been considered: synchronous, asynchronous-conservative and asynchronous-optimistic. These algorithms have been implemented in three multicomputers: a transputer-based Supernode, an Intel Paragon and a network of workstations. The influence that factors such as the characteristics of the simulated models, the organization of the simulators and the characteristics of the target multicomputers have in the performance of the simulations has been measured and characterized.
It is concluded that optimistic parallel simulation techniques are not suitable for the considered kind of models, although they may provide good performance in other environments. A network of workstations is not the right platform for our experiments, because the communication demands of the parallel simulators surpass the abilities of local area networks—the granularity is too fine. Synchronous and conservative parallel simulation techniques perform very well in the Supernode and in the Paragon, specially if the model to simulate is complex or large—precisely the worst case for traditional, sequential simulators. This way, studies previously considered as unrealizable, due to their exceedingly high computational cost, can be performed in reasonable times. Additionally, the spectrum of possibilities of using multicomputers can be broadened to execute more than numeric applications.[ES]En el ámbito del diseño de computadores, la simulación es una herramienta imprescindible para la validación y evaluación de cualquier propuesta arquitectónica. Las ténicas convencionales de simulación, diseñadas para su utilización en computadores secuenciales, son demasiado lentas si el sistema a simular es grande o complejo. El objetivo de esta tesis es buscar técnicas para acelerar estas simulaciones, aprovechando el paralelismo disponible en multicomputadores comerciales, y usar esas técnicas para el estudio de un modelo de encaminador de mensajes. Este encaminador está diseñado para formar infraestructura de comunicaciones de un hipotético computador masivamente paralelo.
En este trabajo se consideran tres técnicas de simulación paralela: síncrona, asíncrona-conservadora y asíncrona-optimista. Estos algoritmos se han implementado en tres multicomputadores: un Supernode basado en Transputers, un Intel Paragon y una red de estaciones de trabajo. Se caracteriza la influencia que tienen en las prestaciones de los simuladores aspectos tales como los parámetros del modelo simulado, la organización del simulador y las características del multicomputador utilizado.
Se concluye que las técnicas de simulación paralela optimista no resultan adecuadas para trabajar con el modelo considerado, aunque pueden ofrecer un buen rendimiento en otros entornos. La red de estaciones de trabajo no resulta una plataforma apropiada para estas simulaciones, ya que una red local no reúne condiciones para la ejecución de aplicaciones paralelas de grano fino. Las técnicas de simulación paralela síncrona y conservadora dan muy buenos resultados en el Supernode y en el Paragon, especialmente si el modelo a simular es complejo o grande—precisamente el peor caso para los algoritmos secuenciales. De esta forma, estudios previamente considerados inviables, por ser demasiado costosos computacionalmente, pueden realizarse en tiempos razonables. Además, se amplía el espectro de posibilidades de los multicomputadores, utilizándolos para algo más que aplicaciones numéricas.Este trabajo ha sido parcialmente subvencionado por la Comisión Interministerial de Ciencia y Tecnología, bajo contrato TIC95-037
Parallel algorithms for the solution of elliptic and parabolic problems on transputer networks
This thesis is a study of the implementation of parallel algorithms for solving
elliptic and parabolic partial differential equations on a network of transputers.
The thesis commences with a general introduction to parallel processing. Here a
discussion of the various ways of introducing parallelism in computer systems and the
classification of parallel architectures is presented.
In chapter 2, the transputer architecture and the associated language OCCAM are
described. The transputer development system (TDS) is also described as well as a
short account of other transputer programming languages. Also, a brief description of
the methodologies for programming transputer networks is given. The chapter is
concluded by a detailed description of the hardware used for the research. [Continues.
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