84,867 research outputs found
Global Grids and Software Toolkits: A Study of Four Grid Middleware Technologies
Grid is an infrastructure that involves the integrated and collaborative use
of computers, networks, databases and scientific instruments owned and managed
by multiple organizations. Grid applications often involve large amounts of
data and/or computing resources that require secure resource sharing across
organizational boundaries. This makes Grid application management and
deployment a complex undertaking. Grid middlewares provide users with seamless
computing ability and uniform access to resources in the heterogeneous Grid
environment. Several software toolkits and systems have been developed, most of
which are results of academic research projects, all over the world. This
chapter will focus on four of these middlewares--UNICORE, Globus, Legion and
Gridbus. It also presents our implementation of a resource broker for UNICORE
as this functionality was not supported in it. A comparison of these systems on
the basis of the architecture, implementation model and several other features
is included.Comment: 19 pages, 10 figure
The AliEn system, status and perspectives
AliEn is a production environment that implements several components of the
Grid paradigm needed to simulate, reconstruct and analyse HEP data in a
distributed way. The system is built around Open Source components, uses the
Web Services model and standard network protocols to implement the computing
platform that is currently being used to produce and analyse Monte Carlo data
at over 30 sites on four continents. The aim of this paper is to present the
current AliEn architecture and outline its future developments in the light of
emerging standards.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 10 pages, Word, 10 figures. PSN
MOAT00
Job Monitoring in an Interactive Grid Analysis Environment
The grid is emerging as a great computational resource but
its dynamic behavior makes the Grid environment unpredictable. Systems and networks can fail, and the
introduction of more users can result in resource starvation.
Once a job has been submitted for execution on the grid,
monitoring becomes essential for a user to see that the job is completed in an efficient way, and to detect any problems
that occur while the job is running. In current environments
once a user submits a job he loses direct control over the job and the system behaves like a batch system: the user
submits the job and later gets a result back. The only
information a user can obtain about a job is whether it is
scheduled, running, cancelled or finished. Today users are
becoming increasingly interested in such analysis grid
environments in which they can check the progress of the
job, obtain intermediate results, terminate the job based on
the progress of job or intermediate results, steer the job to
other nodes to achieve better performance and check the
resources consumed by the job. In order to fulfill their
requirements of interactivity a mechanism is needed that
can provide the user with real time access to information
about different attributes of a job. In this paper we present
the design of a Job Monitoring Service, a web service that
will provide interactive remote job monitoring by allowing
users to access different attributes of a job once it has been submitted to the interactive Grid Analysis Environment
A Taxonomy of Workflow Management Systems for Grid Computing
With the advent of Grid and application technologies, scientists and
engineers are building more and more complex applications to manage and process
large data sets, and execute scientific experiments on distributed resources.
Such application scenarios require means for composing and executing complex
workflows. Therefore, many efforts have been made towards the development of
workflow management systems for Grid computing. In this paper, we propose a
taxonomy that characterizes and classifies various approaches for building and
executing workflows on Grids. We also survey several representative Grid
workflow systems developed by various projects world-wide to demonstrate the
comprehensiveness of the taxonomy. The taxonomy not only highlights the design
and engineering similarities and differences of state-of-the-art in Grid
workflow systems, but also identifies the areas that need further research.Comment: 29 pages, 15 figure
Designing Traceability into Big Data Systems
Providing an appropriate level of accessibility and traceability to data or
process elements (so-called Items) in large volumes of data, often
Cloud-resident, is an essential requirement in the Big Data era.
Enterprise-wide data systems need to be designed from the outset to support
usage of such Items across the spectrum of business use rather than from any
specific application view. The design philosophy advocated in this paper is to
drive the design process using a so-called description-driven approach which
enriches models with meta-data and description and focuses the design process
on Item re-use, thereby promoting traceability. Details are given of the
description-driven design of big data systems at CERN, in health informatics
and in business process management. Evidence is presented that the approach
leads to design simplicity and consequent ease of management thanks to loose
typing and the adoption of a unified approach to Item management and usage.Comment: 10 pages; 6 figures in Proceedings of the 5th Annual International
Conference on ICT: Big Data, Cloud and Security (ICT-BDCS 2015), Singapore
July 2015. arXiv admin note: text overlap with arXiv:1402.5764,
arXiv:1402.575
Maintaining consistency in distributed systems
In systems designed as assemblies of independently developed components, concurrent access to data or data structures normally arises within individual programs, and is controlled using mutual exclusion constructs, such as semaphores and monitors. Where data is persistent and/or sets of operation are related to one another, transactions or linearizability may be more appropriate. Systems that incorporate cooperative styles of distributed execution often replicate or distribute data within groups of components. In these cases, group oriented consistency properties must be maintained, and tools based on the virtual synchrony execution model greatly simplify the task confronting an application developer. All three styles of distributed computing are likely to be seen in future systems - often, within the same application. This leads us to propose an integrated approach that permits applications that use virtual synchrony with concurrent objects that respect a linearizability constraint, and vice versa. Transactional subsystems are treated as a special case of linearizability
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