• Why Cloud?
• History of Cloud
• Evolution of Cloud
• Definition of Cloud
• Cloud Models
• Pros and Cons
• Security Issues
The spread of high-speed broadband
networks in developed countries, the
continual increase in computing power, and
the growth of the Internet have changed
the way in which society manages
information and information services.
Imagine the absence of a power grid
throughout the nation, necessitating the
presence of a generator in every home for
producing electricity. Well, why do we have our
computers filled with software we use
occasionally? Wouldn’t it be meaningful to use
software the same way we use electricity – as
and when we need it?
This was the defining thought behind cloud
In 1960, J.C.R. Licklider is person who brought
the idea of cloud computing to the forefront. In
1961, John McCarthy suggested in a speech at
MIT that computing can be sold like a utility,
like electricity/water. In 1997, Ramnath
Chellappa – first known academic use of the
term “Cloud Computing”
In 1999, Salesforce started delivering
applications to users using a simple website. In
2002, Amazon started Amazon Web Services,
providing services like storage, computation and
even human intelligence. However, the launch
of the Elastic Compute Cloud in 2006, open to
everybody existed. In 2009, Google Apps,
Microsoft Windows Azure, and companies like
Oracle and HP have all joined the game.
Utility (that is available on)
simplifies the meaning of CLOUD -
The Cloud delivers a hosting
environment that is immediate,
flexible, elastic, scalable, secure,
and available – while saving money,
time and resources
• Instead of hosting apps and data on
an individual desktop computer,
everything is hosted in the "cloud"—
an assemblage of computers and
servers accessed via the Internet.
SaaS - 'Software as a Service', describes when users
'rent' or borrow online software instead of actually
purchasing and installing it on their own computers.
Instead of selling you a copy of Microsoft Word for
$300, a cloud computing model would "rent" word
processing software to you through the Internet for $5
a month. You would not install any special software to
your home machine to use this rented online product.
You simply use your modern web browser to login
from any web-enabled computer, and you can access
your word processing documents in the same way that
you would access your Gmail.
PaaS (Platform as a service), as the name
suggests, provides you computing
platforms which typically includes
operating system, programming language
execution environment, database, web
Examples : AWS Elastic Beanstalk,
Heroku, Force.com, Google App Engine.
IaaS(Infrastructure as a service), as the name suggests,
provides you the computing infrastructure, physical or
virtual machines and other resources like virtual-
machine disk image library, block and file-based
storage, firewalls, load balancers, IP addresses, virtual
local area networks etc.
Infrastructure as a Service (IaaS) describes one of the
three main methods of accessing cloud computing
based services. Organisations rent computing power
and disk space and access them from desktop PCs
through a private network or across the internet.
Examples : Amazon EC2, Windows Azure, Rackspace.
Public cloud -- The cloud infrastructure is
made available to the general public or a large
industry group and is owned by an organization
selling cloud services.
Public cloud services may be free or offered on
a pay-per-usage model.
Easy and inexpensive set-up because
hardware, application and bandwidth costs
are covered by the provider.
No wasted resources because you pay for
what you use.
Examples Amazon Elastic Compute Cloud
(EC2), IBM's Blue Cloud, Sun Cloud, Google
AppEngine and Windows Azure Services
Private cloud -- The cloud infrastructure is
operated solely for an organization. It may
be managed by the organization or a third
party and may exist on premise or off
A private cloud can increase efficiency,
decrease costs and offer more security than
a public cloud.
Examples Eucalyptus, Elastra, VMware and
Windows Azure Services Platform.
Hybrid cloud -- The cloud infrastructure is a
composition of two or more clouds (private,
community, or public) that remain unique entities
but are bound together by standardized or
proprietary technology that enables data and
application portability (e.g., cloud bursting for load-
balancing between clouds).
Government departments, universities, central banks
etc. often find this type of cloud useful.
Examples Google Apps for Government, Microsoft
Government Community Cloud
Community cloud -- The cloud infrastructure is shared by
several organizations and supports a specific community
that has shared concerns (e.g., mission, security
requirements, policy, and compliance considerations).
The goal of a community cloud is to have participating
organizations realize the benefits of a public cloud -- such
as multi-tenancy and a pay-as-you-go billing structure --
but with the added level of privacy, security and policy
compliance usually associated with a private cloud. The
community cloud can be either on-premises or off-
premises, and can be governed by the participating
organizations or by a third-party managed service provider
Cloud computing requires an intricate interaction
with the hardware which is very essential to ensure
uptime of the application. It is very helpful to divide
the cloud model into two sections, one is front end
and other is backend.
They are connected via a network and mostly
internet is used for fulfilling the requirement. The
front side is the interface for the user and the back
end is the cloud section for the whole system.
It is the process of moving or transferring data,
application from your machine to cloud and vice-
versa. Moving to the cloud or between cloud
environments presents the usual IT issues, but
the problems are compounded by having data
stored and managed remotely, by external
organizations and often in multiple locations.
Cloud disaster recovery and backup options have
become more common, and some users say they
provide a higher level of protection than
traditional solutions -- at lower cost
How fast is the cloud server’s vCPU?
How quickly do memory and disk respond?
What is the actual network throughput?
Naturally, cloud providers offer systems that are
different "sizes" with regard to power and price.
Offerings typically have two key dimensions: CPU
and memory (RAM).
Supplier’s own privacy & security policies. What are
the supplier’s own procedures and policies? Do
they include physical security? What about removal
of data from premises on removable media? Does
the supplier have an understanding of the role of
the applicable privacy regulatory authorities, and
procedures to respond to enquiries and complaints?
Privacy and data control issues are significant in the
context of cloud computing services.
Access controls Who will have access to the data
(including individuals or roles)? Are there access
audit trails? If there are particular individuals who
will have access to significant amounts of data
(for example, database administrators) how is
their access monitored and managed? Are any
subcontractors involved? How is their access
controlled? Is data encrypted on disk? “in flight”?
Who holds access keys?
Secure Data Transfer
Secure Stored Data
Secure Software Interface
User Access Control
Cloud computing services often provide common
business application online that are accessed from a
web browser, while the software and data are stored
on the servers.
Cloud computing is an umbrella term used to refer to
Internet based development and services
Cloud computing defines virtual storage area which is
provided by cloud providers and accessed by clients
on demand and pay per use. Today, security is one of
the most important factors in computing
environment. Cloud service providers must provide
trust worthy environment. End users must know
about the awareness of security policy.
 Bhushan Lal Sahu, Rajesh Tiwari, “A comprehensive
study on Cloud computing”, International journal of
Advanced Research in Computer science and Software
engineering, volume 2, issue 9, September 2012, ISSN:
 Mladen A. Vouk, “Cloud computing – Issues, Research
and Implementations”, Journal of Computing and
Information technology, CIT 16, 2008, 4, 235-246.
 Anbalagan K., “Cloud computing”, National seminar on
Imminent Trends in Advanced Computing and Technology –
ITIACT’ 13, ISBN: 978-81-924922-3-0.