Cloud computing is a type of internet-based computing where services such as servers, storage, and applications are provided to organizations through the internet. It offers advantages like lower costs, unlimited storage, and universal access to documents from any device. However, it also has disadvantages like requiring a constant internet connection and potential security issues if data is not properly secured. There are different types of cloud models including infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS).

1. CLOUD COMPUTING –
AN OVERVIEW
BY SHASHANK SHEKHAR
B.Tech II year
Sathyabama university
E-mail id- shashankshekhar114@gmail.com

2. INTRODUCION
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Cloud Computing is a type of internet based computing where
different services such as servers, storage and application are
delivered to an organisation’s computer or devices through internet.
Cloud Computing is document centric - documents are not stored in
ones individual computer but on a server which can be accessed by
any one via internet.
Examples of cloud computing includes:• Online file storage
• Social networking sites
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Webmail and online business app

3. CHARACTERISTICS
Common Characteristics:
Massive Scale
Resilient Computing
Homogeneity
Geographic Distribution
Virtualization
Service Orientation
Low Cost Software
Advanced Security
Essential Characteristics:
On Demand Self-Service
Broad Network Access
Rapid Elasticity
Resource Pooling
Measured Service

4. ARCHITECTURE & SERVICE MODELS

5. CLOUD SERVICE MODELS
Software as a
Service (SaaS)
•SalesForce CRM
•LotusLive
Google
App
Engine
Platform as a
Service (PaaS)
Infrastructure as
a Service (IaaS)

6. SOFTWARE AS A SERVICE (SAAS)
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In the Saas model, the cloud providers install and operate
application software in the cloud and cloud user access the
software from the cloud clients. The user does not need to
install and run the application so it simplifies maintenance and
support.
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In Saas the user are not required to handle software upgrades
and patches. Software is delivered in a one to many models.
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With Saas it is easy for enterprises to streamline their
maintenance and support because everything is managed by
vendors
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Examples of SaaS include SalesForce.com, Google Mail,
Google Docs, and so forth

7. PLATFORM AS A SERVICE (PAAS )
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It offers runtime environment or platform to create and deploy.
The organisation is responsible for development, management
and maintenance of the application.
It makes the development, testing and deployment of application
quick, simple and cost effective.
The drawback of this model is that it lacks interoperateability and
portability among providers. If we create an app in one cloud we
cannot move it into another cloud we need to pay a higher price
for it.
Eg. Windows azure, Google app engine, mendix, engine guard,
orangespace etc.

8. INFRASTRUCTURE AS A SERVICE (IAAS
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It is the most basic cloud- service model, provides computer
physical or virtual machines and other resources.
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It offers additional resources such as a virtual machine diskimage library, raw and file based storage, fireworks, IP addresses,
VLANs and software bundles.
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Eg. Amazon EC2, azure services, Google computer engines, HP
cloud, Oracle.
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It makes the acquisition of hardware’s easier. Rather than
purchasing the server, storage, OS it can be accessed through
internet.

9. SERVICE MODELS CONT...

10. TYPES OF CLOUD 
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There are many issues to consider when moving an enterprise
application to the cloud environment. For example, some service
providers are mostly interested in lowering operation cost, while others
may prefer high reliability and security.
Accordingly, there are different types of clouds, each with its own
benefits and drawbacks:• Public clouds
• Private clouds
• Hybrid clouds

11. TYPES OF CLOUD
PUBLIC CLOUD –
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A cloud in which service providers offer their resources as
services to the general public.
Public clouds offer several key benefits to service providers,
including no initial capital investment on infrastructure and
shifting of risks to infrastructure providers.
public clouds lack fine-grained control over data, network and
security settings, due to which their effectiveness is
hampered.
PRIVATE CLOUD –
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Also known as internal clouds, private clouds are designed
for exclusive use by a single organization.

12. TYPES OF CLOUD CONT..•
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A private cloud offers the highest degree of control over
performance, reliability and security.
HYBRID CLOUD –
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A hybrid cloud is a combination of public and private cloud
models that tries to address the limitations of each approach.
In a hybrid cloud, part of the service infrastructure runs in private
clouds while the remaining part runs in public clouds.
Hybrid clouds offer more tighter control, flexibility and security
than both public and private clouds.
Designing a hybrid cloud requires carefully determining the best
split between public and private cloud components.

13. ADVANTAGES
 Lower-Cost Computers for Users •
Since applications run in the cloud, not on the desktop PC, so
desktop PC does no need the processing power or hard disk space
demanded by traditional desktop software.
Lower Software Costs –
•
Instead of purchasing expensive software applications, we can get
most of what we need for free.
Instant Software Updates –
• Another advantage to cloud computing is that you are
no longer faced with choosing between obsolete
software and high upgrade costs.
• When the application is web-based, updates happen automatically

14. ADVANTAGES
 Unlimited Storage Capacity –
• Cloud computing offers virtually limitless storage of nearly
hundreds of Pbytes.
 Increased Data Reliability
• It is data centric so even if our PC crashes, all your data is still
out there in the cloud, still accessible
 Universal Access to Documents • That is not a problem with cloud computing, because you do
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not take your documents with you.
Instead, they stay in the cloud, and you can access them
whenever you have a computer and an Internet connection

15. ADVANTAGES
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Latest Version Availability
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The cloud always hosts the latest version of our documents, it
will automatically update it without users knowledge.
 Improved
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Performance –
Computers in a cloud computing system boot and run faster
because they have fewer programs and processes loaded into
memory.
Easier group collaboration:
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Sharing documents leads directly to better collaboration.
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Many users do this as it is an important advantages of cloud
computing

16. ADVANTAGES
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Device independence we are no longer tethered to a single computer or network.
 Even on moving to a portable device,our applications and
documents are still available.
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Improved document format compatibility.
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You do not have to worry about the documents you create on your
machine being compatible with other users' applications or OS.
There are potentially no format incompatibilities when everyone is
sharing documents and applications in the cloud.

17. DISADVANTAGES
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Requires a constant Internet connection•
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Does not work well with low-speed connections:
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Cloud computing is impossible if there is no Internet
connection.
A dead Internet connection means no work and in areas
where Internet connections are few or inherently unreliable,
this could be a deal-breaker.
Web-based applications require a lot of bandwidth to
download, as do large documents.
General Concerns:
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Each cloud systems uses different protocols and different
APIs
 It
may not be possible to run applications between
different cloud based systems.

18. DISADVANTAGES 
Features might be limited:
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This situation is bound to change, but today many web-based
applications simply are not as full-featured as their desktop-based
applications.
For example, we can do a lot more with Microsoft PowerPoint
than with Google Presentation's web-based offering.
Stored data might not be secure:
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With cloud computing, all your data is stored on the cloud but
unauthorized users can gain access to our confidential data.
Stored data can be lost:
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Theoretically, data stored in the cloud is safe, replicated
across multiple machines.

19. PROVIDERS OF CLOUD COMPUTING

20. CHALLENGES
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Automated service provisioning
Virtual machine migration
Server consolidation
Energy management
Traffic management and analysis
Data security

21. CONCLUSION
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Cloud computing has recently emerged as a compelling
paradigm for managing and delivering services over the
Internet.
The rise of cloud computing is rapidly changing the
landscape of information technology, and ultimately turning
the long-held promise of utility computing into a reality.
However, despite the significant benefits offered by cloud
computing, the current technologies are not matured
enough to realize its full potential.

22. REFERENCES
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Armbrust M et al (2009) Above the clouds: a Berkeley view
of cloud computing. UC Berkeley Technical Report
NIST Definition of cloud computing
(csrc.nist.gov/groups/SNS/cloud- computing/cloud-defv15.doc)
http://en.wikipedia.org/wiki/Cloud_computing
http://aws.amazon.com/ec2
Windows Azure, www.microsoft.com/azure
http://code.google.com/appengine