202 research outputs found
Spider: An overview of an object-oriented distributed computing system
The Spider Project is an object-oriented distributed system which provides a testbed for researchers in the Department of Computer Science, CSUSB, to conduct research on distributed systems
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Enhancing functionality and performance in the PVM network computing system
The research funded by this grant is part of an ongoing research project in heterogeneous distributed computing with the PVM system, at Emory as well as at Oak Ridge Labs and the University of Tennessee. This grant primarily supports research at Emory that continues to evolve new concepts and systems in distributed computing, but it also includes the PI`s ongoing interaction with the other groups in terms of collaborative research as well as software systems development and maintenance. We have continued our second year efforts (July 1995 - June 1996), on the same topics as during the first year, namely (a) visualization of PVM programs to complement XPVM displays; (b) I/O and generalized distributed computing in PVM; and (c) evolution of a multithreaded concurrent computing model. 12 refs
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Prototyping a process-centered environment
This paper describes an experimental system developed and used as a vehicle for prototyping the Arcadia-1 software development environment. Prototyping is viewed as a knowledge acquisition process and is used to reduce risks in software development by gaining rapid feedback about the suitability of a production system before the system is completed. Prototyping a software development environment is particularly important due to the lack of experience with them. There is an acute need to acquire knowledge about user interaction requirements for software environments. These needs are especially important for the Arcadia project, as it is one of the first attempts to construct a process-centered environment. Our prototyping effort addresses questions about effective interaction with a process-centered environment by simulating how Arcadia-1 would interact with users in a representative range of usage scenarios. We built a prototyping system, called PRODUCER, and used it to generate a variety of prototypes simulating user interactions with Arcadia-1 process programs.Experience with PRODUCER indicates that our approach is effective at risk reduction. The prototypes greatly improved communication with our customer. They confirmed some of our design decisions but also redirected our research efforts as a result of unexpected insight. We also found that prototyping usage scenarios provides conceptual guides and design information for process programmers. Most of the benefits of our prototyping effort derive from developing and interacting with usage scenarios, so our approach is generalizable to other prototyping systems. This paper reports on our prototyping approach and our experience in prototyping a process-centered environment
An occam Style Communications System for UNIX Networks
This document describes the design of a communications system which provides occam style communications primitives under a Unix environment, using TCP/IP protocols, and any number of other protocols deemed suitable as underlying transport layers. The system will integrate with a low overhead scheduler/kernel without incurring significant costs to the execution of processes within the run time environment. A survey of relevant occam and occam3 features and related research is followed by a look at the Unix and TCP/IP facilities which determine our working constraints, and a description of the T9000 transputer's Virtual Channel Processor, which was instrumental in our formulation. Drawing from the information presented here, a design for the communications system is subsequently proposed. Finally, a preliminary investigation of methods for lightweight access control to shared resources in an environment which does not provide support for critical sections, semaphores, or busy waiting, is made. This is presented with relevance to mutual exclusion problems which arise within the proposed design. Future directions for the evolution of this project are discussed in conclusion
Support for flexible and transparent distributed computing
Modern distributed computing developed from the traditional supercomputing community rooted firmly
in the culture of batch management. Therefore, the field has been dominated by queuing-based resource
managers and work flow based job submission environments where static resource demands needed be
determined and reserved prior to launching executions. This has made it difficult to support resource
environments (e.g. Grid, Cloud) where the available resources as well as the resource requirements
of applications may be both dynamic and unpredictable. This thesis introduces a flexible execution
model where the compute capacity can be adapted to fit the needs of applications as they change during
execution. Resource provision in this model is based on a fine-grained, self-service approach instead
of the traditional one-time, system-level model. The thesis introduces a middleware based Application
Agent (AA) that provides a platform for the applications to dynamically interact and negotiate resources
with the underlying resource infrastructure.
We also consider the issue of transparency, i.e., hiding the provision and management of the distributed
environment. This is the key to attracting public to use the technology. The AA not only replaces
user-controlled process of preparing and executing an application with a transparent software-controlled
process, it also hides the complexity of selecting right resources to ensure execution QoS. This service
is provided by an On-line Feedback-based Automatic Resource Configuration (OAC) mechanism cooperating
with the flexible execution model. The AA constantly monitors utility-based feedbacks from the
application during execution and thus is able to learn its behaviour and resource characteristics. This
allows it to automatically compose the most efficient execution environment on the fly and satisfy any
execution requirements defined by users. Two policies are introduced to supervise the information learning
and resource tuning in the OAC. The Utility Classification policy classifies hosts according to their
historical performance contributions to the application. According to this classification, the AA chooses
high utility hosts and withdraws low utility hosts to configure an optimum environment. The Desired
Processing Power Estimation (DPPE) policy dynamically configures the execution environment according
to the estimated desired total processing power needed to satisfy users’ execution requirements.
Through the introducing of flexibility and transparency, a user is able to run a dynamic/normal
distributed application anywhere with optimised execution performance, without managing distributed
resources. Based on the standalone model, the thesis further introduces a federated resource negotiation
framework as a step forward towards an autonomous multi-user distributed computing world
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