Page 40 - DCAP609_CLOUD_COMPUTING

Unit 3: Developing Cloud Services

With PaaS, developers can finally focus on creating useful applications to achieve immense Notes
success in their respective businesses. They no longer have to worry about managing complex
hardware and software arrangements.

3.3.3 Web Services

Web services also referred to as application services are services that include some combination
of programming and data, but possibly includes human resources as well that are made available
from a business’s Web server for Web users or other Web-connected programs. A Web Service
can convert your applications into Web-applications. Web services are published, found and
used through the Web.
A web service is an API that can be accessed over the Internet. The service is then executed on a
remote system that hosts the requested services. This type of web API lets developers exploit
shared functionality over the Internet. The result is a customized web-based application where
a large chunk of that application is delivered by a third party, thus easing bandwidth demands
and development processes for the custom program.
“Mash-ups” created by users of the Google Maps API are perfect examples of Web services. With
these custom apps, the engine that creates the map itself is provided by Google while the data
that serves the map is provided by the developer. The developer does not have to serve a map
application. He just needs to hook into Google’s web API.
A web service is a software system identified by a URL, whose public interfaces and bindings are
defined and described using XML. Providers of Web services are generally known as application
service providers.
Web services include major services such as Customer Relationship Management (CRM) and
storage management along with a few limited services such as checking bids for an auction item
and furnishing stock quotes. Increased creation and availability of such services is becoming a
major Web trend. Web services are increasingly enabled by the use of the Extensible Markup
Language (XML) as a means of standardizing data formats and exchanging data besides providing
the standardization and wide availability to users and businesses of the Internet. XML is the
foundation for the Web Services Description Language (WSDL).
Web services are advantageous as they include faster and lower-cost application development,
reduced storage demands, leaner applications and reduced bandwidth demands.

Web Services allow the business logic of many different systems to be exposed over the Web.
This gives your applications the freedom to choose the Web Services that they need. Instead of
re-inventing the wheel for each client, you need only include additional application-specific
business logic on the client-side. This allows you to develop services and/or client-side code
using the languages and tools that you want. This is a significant benefit of Web Services. Web
Services usually work outside of private networks, offering developers a non-proprietary route
to their solutions. Therefore, the services developed have a longer life-span, offering better
return on investment of the developed service. Web Services also let developers use their
preferred programming languages. In addition, Web Services are nearly platform-independent
due to the use of standards-based communications methods.

3.3.4 On-demand (OD) Computing

On demand computing also referred to as ODC is a business computing model in which
computing resources are made available to the user on an “as needed” basis.

ODC makes computing resources such as storage capacity, software applications and
computational speed available to users as and when needed for specific temporary projects,

LOVELY PROFESSIONAL UNIVERSITY 35