Message Queue Manager

The conventional way of debugging is to examine the program's state at various points during execution. With the addition of message passing as a means of communication and synchronization in message passing programs, the state of pending message operations also needs to be examined. Current parallel debuggers or analysis tools offer little information on the status of message operations. When they do, the information presented is voluminous and hard to assimilate. The Message Queue Manager (MQM), a Parallel Tools Consortium project, provides a simple and direct way to determine the status of pending message operations during program execution. It has been designed and developed as a modular component that can be incorporated into a parallel debugger or other analysis tools on a variety of hardware platforms. MQM obtains a snapshot of message queues from the underlying message passing system (using a standard interface at some breakpoint or other pause in execution) and presents the data graphically. Two levels of information are available -- an overview gives an abstraction of message queue lengths, while a detailed view shows pending message operations for specific processes. The overview can display a large number of processes in a reasonably small screen, accommodating massively parallel programs. Several filtering mechanisms allow the user easily control how much information is shown

Parallel solution of power system linear equations

At the heart of many power system computations lies the solution of a large sparse set of linear equations. These equations arise from the modelling of the network and are the cause of a computational bottleneck in power system analysis applications. Efficient sequential techniques have been developed to solve these equations but the solution is still too slow for applications such as real-time dynamic simulation and on-line security analysis. Parallel computing techniques have been explored in the attempt to find faster solutions but the methods developed to date have not efficiently exploited the full power of parallel processing. This thesis considers the solution of the linear network equations encountered in power system computations. Based on the insight provided by the elimination tree, it is proposed that a novel matrix structure is adopted to allow the exploitation of parallelism which exists within the cutset of a typical parallel solution. Using this matrix structure it is possible to reduce the size of the sequential part of the problem and to increase the speed and efficiency of typical LU-based parallel solution. A method for transforming the admittance matrix into the required form is presented along with network partitioning and load balancing techniques. Sequential solution techniques are considered and existing parallel methods are surveyed to determine their strengths and weaknesses. Combining the benefits of existing solutions with the new matrix structure allows an improved LU-based parallel solution to be derived. A simulation of the improved LU solution is used to show the improvements in performance over a standard LU-based solution that result from the adoption of the new techniques. The results of a multiprocessor implementation of the method are presented and the new method is shown to have a better performance than existing methods for distributed memory multiprocessors

Distributed parallel processing and the factoring problem

This research is concerned with distributed parallel processing and how a computer cluster/network may be used to solve large and computationally expensive problems, specifically in the area of cryptography and the problem of factoring very large numbers. Until recently few methods or systems were capable of harnessing the full potential power of a distributed environment. In order to realise the full potential of computer clusters, specially designed distributed parallel processing systems are needed. Cryptography is the science of secure communications and has recently become commercially important and widely used. This research focuses on public key cryptography, the security of which is based on the difficulty of factoring extremely large numbers. The research described in this thesis covers parallelism and distributed computing and describes an implementation of a distributed processing system. An introduction to cryptography is presented, followed by a discussion on factoring which centres on describing and implementing a distributed parallel version of Lenstra’s Elliptic Curve factoring method

On-line Distributed Debugging on Scaleable Multicomputer Architectures

. Debugging parallel programs is one of the most tedious jobs in programming scalable multiprocessor architectures. Due to the distributed resources of these machines, programming is often architecture dependent. Most development tools still reflect this dependency even during the analysis phase of parallel programs. This paper presents the distributed debugger DETOP, which offers a global name space and hides architectural features like the mapping of processes. DETOP is part of the integrated tool environment TOPSYS implemented on iPSC hypercubes, networks of SPARCstations and partly on Transputer systems. 1 Introduction Some compute intensive applications, e.g. fluid dynamics and simulations, require computing performance far beyond the performance of today's supercomputers. Many computer scientists claim that the performance necessary for these "grand challenges" can only be reached with parallel distributed memory computers. Although some of these computers already offer hardwar..

Resilience-Building Technologies: State of Knowledge -- ReSIST NoE Deliverable D12

This document is the first product of work package WP2, "Resilience-building and -scaling technologies", in the programme of jointly executed research (JER) of the ReSIST Network of Excellenc

Summary of Research 1994

The views expressed in this report are those of the authors and do not reflect the official policy or position of the Department of Defense or the U.S. Government.This report contains 359 summaries of research projects which were carried out under funding of the Naval Postgraduate School Research Program. A list of recent publications is also included which consists of conference presentations and publications, books, contributions to books, published journal papers, and technical reports. The research was conducted in the areas of Aeronautics and Astronautics, Computer Science, Electrical and Computer Engineering, Mathematics, Mechanical Engineering, Meteorology, National Security Affairs, Oceanography, Operations Research, Physics, and Systems Management. This also includes research by the Command, Control and Communications (C3) Academic Group, Electronic Warfare Academic Group, Space Systems Academic Group, and the Undersea Warfare Academic Group

NASA Tech Briefs, October 1996

Topics covered include: Sensors; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Mathematics and Information Sciences; Life Sciences; Books and Reports