cloud computing is a growing field in computer science. This ppt can help the beginners understand it. contains information about PaaS, Iaas, SaaS and other concepts of Cloud Computing.It also contains a video on cloud computing.

2. Cloud computing is defined as the practice of using a network
of remote servers hosted on the Internet to store, manage, and
process data, rather than a local server or a personal computer.
The Five Principles of Cloud Computing:-
1. Resources pooling
2. Virtualization.
3. Elasticity.
4. Automatic/easy resource deployment.
5. Metered billing.

4. • There are three types of cloud computing providers-
• Infrastructure as a Service (IaaS)
• Platform as a Service (PaaS).
• Software as a Service (SaaS).

5. Infrastructure as a Service
(IaaS)
• Infrastructure as a service provides companies with
computing resources including servers, networking, storage,
and data center space on a pay-per-use basis.
• IaaS providers offer hardware and the bare minimum
software for users to develop on e.g. virtual servers, hard
disk space. Users have broad control over the services
offered by IaaS providers as they are able to configure
settings to a very large extent and they are free to implement
and utilize any form of software and programming
environment on top of the services. An example of an IaaS
provider is Rackspace

6. Platform as a Service (PaaS)
• For services offered by PaaS providers, users have very
little control over their software and programming
environment. This is because PaaS providers implement
a software layer over the hardware they offer, forcing
users to work with the providers' software layer. This is
not necessarily a bad thing as PaaS providers reduce the
technical expertise needed for users to create their own
web application.
• Example – Google app engine.

7. Software as a Service (SaaS)
• SaaS providers basically offer software for users over the
Internet through a web browser. An example of a SaaS
is Google Docs, where one can edit documents through
the software delivered over the Internet. The main
advantage of using a SaaS is that you do not have to
worry about installation, storage space, data loss due to
PC crashes or patches - the cloud computing provider
handles all that and simply delivers the software to you
in your web browser.

8. Deployment models
• Public cloud :- Private cloud is cloud infrastructure operated solely
for a single organization, whether managed internally or by a third-
party and hosted internally or externally.
• Public cloud:- A cloud is called a "public cloud" when the services
are rendered over a network that is open for public use. Technically
there may be little or no difference between public and private
cloud architecture
• Community cloud:- Community cloud shares infrastructure
between several organizations from a specific community with
common concerns (security, compliance, jurisdiction, etc.), whether
managed internally or by a third-party and hosted internally or
externally. The costs are spread over fewer users than a public
cloud (but more than a private cloud), so only some of the cost
savings potential of cloud computing are realized.

9. • Hybrid cloud :- Hybrid cloud is a composition of two or
more clouds (private, community or public) that remain
distinct entities but are bound together, offering the benefits
of multiple deployment models. Hybrid cloud can also mean
the ability to connect collocation, managed and/or dedicated
services with cloud resources.
• To be effective, a management strategy for hybrid cloud
deployment should address configuration
management, change control, security, fault
management and budgeting. Because a hybrid cloud
combines public cloud and private data center principles, it's
possible to plan a hybrid cloud deployment from either of
these starting points.

10. Architecture
Cloud architecture, the systems architecture of the software systems involved in the delivery of
cloud computing, typically involves multiple cloud components communicating with each other
over a loose coupling mechanism such as a messaging queue. Elastic provision implies
intelligence in the use of tight or loose coupling as applied to mechanisms such as these and
others.
• The Intercloud
The Intercloud is an interconnected global "cloud of clouds" and an extension of the Internet
"network of networks" on which it is based.
• Cloud engineering
Cloud engineering is the application of engineering disciplines to cloud computing. It brings
a systematic approach to the high-level concerns of commercialization, standardization,
and governance in conceiving, developing, operating and maintaining cloud computing
systems. It is a multidisciplinary method encompassing contributions from diverse areas
such as systems, software, web, performance, information, security, platform, risk,
and quality engineering.

11. Privacy issues
• The increased use of cloud computing services such as Gmail and Google Docs has pressed the
issue of privacy concerns of cloud computing services to the utmost importance. The provider of
such services lie in a position such that with the greater use of cloud computing services has given
access to a plethora of data. This access has the immense risk of data being disclosed either
accidentally or deliberately. Privacy advocates have criticized the cloud model for giving hosting
companies' greater ease to control—and thus, to monitor at will—communication between host
company and end user, and access user data (with or without permission). Instances such as
the secret NSA program, working with AT&T, and Verizon, which recorded over 10 million
telephone calls between American citizens, causes uncertainty among privacy advocates, and the
greater powers it gives to telecommunication companies to monitor user activity.
• Cloud computing poses privacy concerns because the service provider can access the data that is
on the cloud at any time. It could accidentally or deliberately alter or even delete information. This
becomes a major concern as these service providers, who employ administrators which can leave
room for potential unwanted disclosure of information on the cloud.

12. Privacy solutions
• Solutions to privacy in cloud computing include policy
and legislation as well as end users' choices for how data
is stored. The cloud service provider needs to establish
clear and relevant policies that describe how the data of
each cloud user will be accessed and used. Cloud service
users can encrypt data that is processed or stored within
the cloud to prevent unauthorized access.

13. The Future
According to Gartner's Hype cycle, cloud computing has reached a maturity that leads it into a productive phase.
This means that most of the main issues with cloud computing have been addressed to a degree that clouds have
become interesting for full commercial exploitation. This however does not mean that all the problems listed above
have actually been solved, only that the according risks can be tolerated to a certain degree. Cloud computing is
therefore still as much a research topic, as it is a market offering.
• In 2012 the European Commission has issued an analysis of the relevance of the open research issues for
commercial stabilisation in which various experts from industry and academia identify in particular the
following major concerns:
• open interoperation across (proprietary) cloud solutions at IaaS, PaaS and SaaS levels
• managing multitenancy at large scale and in heterogeneous environments
• dynamic and seamless elasticity from inhouse clouds to public clouds for unusual (scale, complexity) and/or
infrequent requirements data management in a cloud environment, taking the technical and legal constraints
into consideration
These findings have been refined into a research roadmap proposed by the Cloud Computing Expert Group on
Research in December 2012 which tries to lay out a timeline for the identified research topics according to their
commercial relevance. With the 8th Framework Programmes for Research and Technological Development, the
European Commission is trying to support the according research work along the lines of the Europe 2020 strategy.

14. Cloud
Service
Provider
s