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A Web Service is an interface
that describes a collection of operations that are network
accessible. They are built on XML based technologies and messaging.
They use XML schemas to mark-up and describe services and their
operations. Web Services commonly use the Simple Object Access
Protocol (SOAP) as a communication protocol over HTTP- when this is
not appropriate for performance reasons, a different protocol may be
It is the GSA that pulls
together Open Grid Architecture and Web Services to form Grid
Services. Grid Services are dynamic, transient, and have state, in
other words have a finite lifetime, and are defined by a
well-defined set of interfaces and behaviors. OGSA interfaces and
behaviors describing Grid Services can be written in an XML schema
based WSDL document ? other implementations are possible.
Perception of Grid
Since the Grid Architecture
involves interoperability and sharing of resources within enterprise
and across enterprises, it is often pondered if the Grid is
synonymous with Internet or if the grid is an alternative to the
Internet. Actually, the Grid is a set of additional protocols and
services that build on Internet protocols and services to support
the creation and use of computation and data-enriched environments.
In addition, it should be noted that any resource that is on the
Grid is also, by definition, on the Net.
The Grid is perceived as a
source of free CPU cycles. However, Grid computing does not imply
unrestricted access to resources; rather it is about controlled
sharing. The CPU cycles are normally used and controlled by resource
policies defined. Usage of such resources depends on group
membership, ability to pay, and so forth.
Grid experts believe that the
Grid makes high-performance computers superfluous. The thousands of
processors that may be accessible within a Virtual Organization
represent a significant source of computational power. This does not
imply, however, that traditional high-performance computers are
Where Are We on the Grid?
As the Grid is gradually moving
into the commercial world, many of the standards are finalized and
many of niche software players are churning out software components
needed for grid integration.
There are many IT vendors, in
every aspect of the grid technology, who have released various
strategies and solutions. Figure 2.3 gives an idea of various
players in the grid technology.
Figure 2.3: Grid Universe and
the Key Players.
For the success and wide
adoption of any new technology or new orientation, commercialization
efforts are very important. For the Grid to become a widespread
technology, in the same way the Internet became a mainstream
technology and communication media, it needs to enter or penetrate
into the commercial world. Commercialization provides necessary
impetus for growth and funding.
There are many signs of Grid
commercialization, even though they are at early stages. Some of
examples of major business areas where Grid computing is seen as a
* Life Sciences ? Grid is used
for analyzing strings of biological and chemical information.
* Financial Services ? For
processing long running, complex financial models and arriving at
decisions that are more accurate.
* Higher Education ? For
enabling advanced, data and computing intensive research.
* Engineering Services ? In the
automotive and aerospace industry, for collaborative design and data
* Government ? For enabling
multi-departmental computing projects in both civil and military
* Collaborative Games ? where
many players participate simultaneously and use the computing
resources for playing online games.
The following is an interesting
case study, which shows the gradual adaptation of this new and
revolutionary grid technology into the commercial world.