grid computing

1. Prof. Neeraj Bhargava
Pooja Dixit
Department of Computer Science
School of Engineering & System Sciences
MDS, University Ajmer, Rajasthan, India
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2.  OGSI defines mechanisms for creating, managing, and exchanging
information among grid services. A grid service is a Web service
that conforms to a set of conventions (interfaces and behaviors)
that define how a client interacts with a grid capability.
 the OGSI specifications define the standard interfaces and
behaviors of a grid service, building on a Web services base. This
approach provides a common and open standards-based
mechanism to access various grid services using existing industry
standards such as SOAP, XML, and WS-Security.
 The architecture for grid computing is defined in the Open Grid
Services Architecture that describes the overall structure and the
services to be provided in grid environments.
 Figure 1 depicts the network’s role in supporting a (standardized)
grid. Figure 2 is the reference diagram that illustrates the OGSA.
The companion implementation standard, the OGSI, is a formal
specification of the concepts described by the OGSA; it specifies a
set of service primitives that define a nucleus of behavior common
to all Grid Services .
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3. Figure:1 Networking Role
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4. Figure 2 Basic Functional model for Grid Computing
Figure 3 OGSA reliance on OGSI
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5.  standards are critical to making the computing utility concept a reality. On
the other hand, a corporate user just looking to secure better utilization of
its platforms and internal resources could start with a vendor-based
solution and then move up to a standards-based solution in due course.
 Some specific areas where a lack of grid standards limit deployment are:
◦ Data management. For a grid to work effectively, there is a need to store information
and distribute it. Without a standardized method for describing the work and how it
should be exchanged, one quickly encounters limits related to the flexibility and
interoperability of the grid.
◦ Dispatch management. There are a number of approaches that can be used to handle
brokering of work units and to distribute these work units to client resources. Again,
not having a st andard method for this restricts the service providers that can connect
to the grid and accept units of work from the grid; this also restricts the ability of grid
services users to submit work.
◦ Information services. Metadata6 about the grid service helps the system to distribute
information. The metadata is used to identify requesters (grid users), providers, and
their respective requirements and resource availability.
◦ Scheduling. We work must be scheduled across the service providers to ensure they are
kept busy. To accomplish this, information about remote loads must be collected and
administered. A standardized method of describing the grid service enables grid
implementations to specify how work is to be scheduled.
◦ Security. Without a standard for the security of a grid service and for the secure
distribution of work units, one runs the risk of distributing information to the “wrong”
clients. Although proprietary methods can provide a level of security, they limit
accessibility.
◦ Work unit management. Grid services require management of the distribution of work
units to ensure that the work is uniformly distributed over the service providers. Without
a standard way of advertising and managing this process, efficiencies are degraded.
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6. ◦ Increased effective computing capacity. When the resources utilize the same
conventions, interfaces, and mechanisms, one can transparently switch
jobs among grid systems, both from the perspective of the server as well
as from the perspective of the client. This allows grid users to use more
capacity and allows clients a more extensive choice of projects that can
be supported on the grid. Hence, with a gamut of platforms and
environments supported, along with the ability to more easily publish the
services available, there will be an increase in the effective computing
capacity.
◦ Interoperability of resources. Grid systems can be more easily and
efficiently developed and deployed when utilizing a variety of languages
and a variety of platforms. For example, it is desirable to mix service-
provider components, work-dispatch tracking systems, and systems
management; this makes it easier to dispatch work to service providers
and for service providers to support grid services.
◦ Speed of application development. Using middleware (and/or toolkits)
based on a standard expedites the development of grid-oriented
applications supporting a business environment. Rather than spending
time developing communication and management systems to help
support the grid system, the planner can, instead, spend time
optimizing the business/algorithmic logic related to the processing the
data.
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7.  Figure depicts For example, standard APIs enable application portability; without standard APIs, application
portability is difficult to accomplish (different platforms access protocols in different ways). Standards
enable cross-site interoperability; without standard protocols, interoperability is difficult to achieve.
Standards also enable the deployment of a shared infrastructure.
 Use of the OGSI standard, therefore, provides the following benefits Figure. depicts an example of the
environment that one aims to achieve. For example, standard APIs enable application portability; without
standard APIs, application portability is difficult to accomplish (different platforms access protocols in
different ways). Standards enable cross-site interoperability; without standard protocols, interoperability is
difficult to achieve. Standards also enable the deployment of a shared infrastructure. Use of the OGSI
standard, therefore, provides the following benefits [73]
Example of service-oriented architecture
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