1. CloudComputing
DEF: Cloud Computing is a virtualized
compute power and storage delivered via
platform-agnostic infrastructures of
abstracted hardware and software
accessed over the Internet. These shared,
on-demand IT resources, are created and
disposed of efficiently, are dynamically
scalable through a variety of
programmatic interfaces and are billed
variably based on measurable usage.
Cloud computing is a general term for
anything that involves delivering hosted
services over the Internet. These services
are broadly divided into three categories:
Infrastructure-as-a-Service (IaaS),
Platform-as-a-Service (PaaS) and
Software-as-a-Service (SaaS). The name
cloud computing was inspired by the
cloud symbol that's often used to
represent the Internet in flowcharts and
diagrams
A cloud can be private or public. A
public cloud sells services to anyone on
the Internet. (Currently, Amazon Web
Services is the largest public cloud
provider.) A private cloud is a
proprietary network or a data center that
supplies hosted services to a limited
number of people. When a service
provider uses public cloud resources to
create their private cloud, the result is
called a virtual private cloud. Private or
public, the goal of cloud computing is to
provide easy, scalable access to
computing resources and IT services.
Infrastructure-as-a-Service like Amazon
Web Services provides virtual server
instanceAPI) to start, stop, access and
configure their virtual servers and
storage. In the enterprise, cloud
computing allows a company to pay for
only as much capacity as is needed, and
bring more online as soon as required.
Because this pay-for-what-you-use
model resembles the way electricity, fuel
and water are consumed, it's sometimes
referred to as utility computing.
Platform-as-a-service in the cloud is
defined as a set of software and product
development tools hosted on the
provider's infrastructure. Developers
create applications on the provider's
platform over the Internet. PaaS
providers may use APIs, website portals
or gateway software installed on the
customer's computer. Force.com, (an
outgrowth of Salesforce.com) and
GoogleApps are examples of PaaS.
Developers need to know that currently,
there are not standards for
interoperability or data portability in the
cloud. Some providers will not allow
software created by their customers to be
moved off the provider's platform.
In the software-as-a-service cloud
model, the vendor supplies the hardware
infrastructure, the software product and
interacts with the user through a front-
end portal. SaaS is a very broad market.
Services can be anything from Web-
based email to inventory control and
database processing. Because the service
provider hosts both the application and
the data, the end user is free to use the
service from anywhere.
Types:

2. Public Cloud: Computing
infrastructure is hosted at the
vendor’s premises. The customer
has no visibility over the location
of the cloud computing
infrastructure. The computing
infrastructure is shared between
organizations.
Private Cloud:
Computing architecture is
dedicated to the customer and is
not shared with other
organisations. They are
expensive and are considered
more secure than Public Clouds.
Private clouds may be externally
hosted ones as well as in premise
hosted clouds.
diagram is available under a
Creative Commons Attribution
ShareAlike 3.0 license in PNG
and SVG formats from the
Wikimedia Commons (Cloud
computing types.svg
Hybrid Cloud: Organisations
host some critical, secure
applications in private clouds.
The not so critical applications
are hosted in the public cloud.
The combination is known as
Hybrid Cloud. Cloud bursting is
the term used to define a system
where the organisation uses its
own infrastructure for normal
usage, but cloud is used for peak
loads.
Community Cloud: The
cloud infrastructure is shared
between the organizations of the
same community. For example,
all the government agencies in a
city can share the same cloud but
not the non government agencies.
Layers
Once an internet protocol connection is
established among several computers, it
is possible to share services within any
one of the following layers.
Client
See also: Category:Cloud clients
A cloud client consists of computer
hardware and/or computer software that
relies on cloud computing for
application delivery and that is in
essence useless without it. Examples
include some computers (example:
Chromebooks), phones (example:
Google Nexus series) and other devices,

3. operating systems (example: Google
Chrome OS), and browsers.[34][35][36]
Application
See also: Category:Cloud applications
Cloud application services or "Software
as a Service (SaaS)" deliver software as
a service over the Internet, eliminating
the need to install and run the
application on the customer's own
computers and simplifying maintenance
and support.
Platform
See also: Category:Cloud platforms
Cloud platform services, also known as
platform as a service (PaaS), deliver a
computing platform and/or solution
stack as a service, often consuming
cloud infrastructure and sustaining cloud
applications.[37]
It facilitates deployment
of applications without the cost and
complexity of buying and managing the
underlying hardware and software
layers.[38][39]
Cloud computing is
becoming a major change in our
industry, and one of the most important
parts of this change is the shift of cloud
platforms. Platforms let developers write
certain applications that can run in the
cloud, or even use services provided by
the cloud. There are different names
being used for platforms which can
include the on-demand platform, or
Cloud 9. It's your choice on what you
would like to call the platform, but they
all have great potential in developing.
When development teams create
applications for the cloud, they must
build its own cloud platform.
Infrastructure
See also: Category:Cloud infrastructure
Cloud infrastructure services, also
known as "infrastructure as a service"
(IaaS), deliver computer infrastructure –
typically a platform virtualisation
environment – as a service, along with
raw (block) storage and networking.
Rather than purchasing servers,
software, data-center space or network
equipment, clients instead buy those
resources as a fully outsourced service.
Suppliers typically bill such services on
a utility computing basis; the amount of
resources consumed (and therefore the
cost) will typically reflect the level of
activity.[40]
Server
The servers layer consists of computer
hardware and/or computer software
products that are specifically designed
for the delivery of cloud services,
including multi-core processors, cloud-
specific operating systems and combined
offerings
Cloud “Applications”
SaaS resides here
Most common Cloud / Many
providers of different services
Examples: SalesForce, Gmail,
Yahoo! Mail, Quicken Online
Advantages: Free, Easy,
Consumer Adoption
Disadvantages: Limited
functionality, no control or
access to underlying technology

4. Cloud “Platforms”
“Containers”
“Closed” environments
Examples: Google App Engine,
Heroku, Mosso, Engine Yard,
Joyent or Force.com (SalesForce
Dev Platform)
Advantages: Good for
developers, more control than
“Application” Clouds, tightly
configured
Disadvantages: Restricted to
what is available, other
dependencies
Cloud “Infrastructure
Provide “Compute” and
“Storage” clouds
Virtualization layers
(hardware/software)
Examples: Amazon EC2,
GoGrid, Amazon S3, Nirvanix,
Linode
Advantages: Full control of
environments and infrastructure
Disadvantages: premium price
point, limited competition
Cloud “Extenders” (Wild Card)
Provides extension to Cloud
Infrastructure and Platforms with
basic functionality
Examples: Amazon SimpleDB,
Amazon SQS, Google BigTable
Advantages: Extends
functionality of Compute &
Storage Clouds to integrate with
legacy system or other clouds
Disadvantages: Sometimes
requires use of specific Platforms
or Infrastructure
Cloud “Aggregators” (Wild Card)
Sits on top of various Cloud
Infrastructures for management
Examples: RightScale, Appistry
Advantages: Provides more
options for Cloud environments
Disadvantages: Dependent on
Cloud Providers
Advantages of Cloud Computing

5. • Lower computer costs:
– You do not need a high-
powered and high-priced
computer to run cloud
computing's web-based
applications.
– Since applications run in
the cloud, not on the
desktop PC, your desktop
PC does not need the
processing power or hard
disk space demanded by
traditional desktop
software.
• Improved performance:
– With few large programs
hogging your computer's
memory, you will see
better performance from
your PC.
– Computers in a cloud
computing system boot
and run faster because
they have fewer programs
and processes loaded into
memory…
• Reduced software costs:
– Instead of purchasing
expensive software
applications, you can get
most of what you need
for free-ish!
– That is right - most cloud
computing applications
today, such as the Google
Docs suite, are totally
free.
That is a lot better than
paying $200+ for similar
Microsoft Office software
- which alone may be
justification for switching
to cloud applications
• 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 -
available the next time
you log into the cloud.
– When you access a web-
based application, you get
the latest version -
without needing to pay
for or download an
upgrade.
• Improved document format
compatibility.
– You do not have to worry
about the documents you
create on your machine
being compatible with
other users' applications
or operating systems.
– Where Word 2007
documents cannot be
opened on a computer
running Word 2003, all
documents can be read!
There are potentially no
format incompatibilities
when everyone is sharing
documents and
applications in the cloud
• Unlimited storage capacity:
– Cloud computing offers
virtually limitless storage.

6. – Your computer's current
200 Gbyte hard drive is
small compared to the
hundreds of Pbytes
available in the cloud.
– Whatever you need to
store, you can.
• Increased data reliability:
– Unlike desktop
computing, in which if a
hard disk crashes and
destroy all your valuable
data, a computer crashing
in the cloud should not
affect the storage of your
data.
– That also means that if
your personal computer
crashes, all your data is
still out there in the cloud,
still accessible.
– In a world where few
individual desktop PC
users back up their data
on a regular basis, cloud
computing is a data-safe
computing platform!
• Universal document access:
– That is not a problem
with cloud computing,
because you do 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.
– All your documents are
instantly available from
wherever you are.
• Latest version availability:
– Another document-
related advantage of
cloud computing is that
when you edit a
document at home, that
edited version is what you
see when you access the
document at work.
The cloud always hosts
the latest version of your
documents; as long as
you are connected, you
are not in danger of
having an outdated
version
• Easier group collaboration:
– Sharing documents leads
directly to better
collaboration.
– Many users do this as it is
an important advantages
of cloud computing -
multiple users can
collaborate easily on
documents and projects.
– Because the documents
are hosted in the cloud,
not on individual
computers, all you need is
an Internet connection,
and you are collaborating.
• Device independence.
– You are no longer
tethered to a single
computer or network.
– Changes to computers,
applications and
documents follow you
through the cloud.
– Move to a portable
device, and your
applications and
documents are still
available.

7. Disadvantages of Cloud Computing
• Requires a constant Internet
connection:
– Cloud computing is
impossible if you cannot
connect to the Internet.
– Since you use the Internet
to connect to both your
applications and
documents, if you do not
have an Internet
connection you cannot
access anything, even
your own documents.
– A dead Internet
connection means no
work and in areas where
Internet connections are
few or inherently
unreliable, this could be a
deal-breaker.
When you are offline,
cloud computing simply does not work
• Can be slow:
– Even with a fast
connection, web-based
applications can
sometimes be slower than
accessing a similar
software program on your
desktop PC.
– Everything about the
program, from the
interface to the current
document, has to be sent
back and forth from your
computer to the
computers in the cloud.
– If the cloud servers
happen to be backed up at
that moment, or if the
Internet is having a slow
day, you would not get
the instantaneous access
you might expect from
desktop applications.
• Features might be limited:
– 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, you can do
a lot more with Microsoft
PowerPoint than with
Google Presentation's
web-based offering.
– The basics are similar,
but the cloud application
lacks many of
PowerPoint's advanced
features.
– If you are a power user,
you might not want to
leap into cloud computing
just yet.
• HPC Systems:
– Not clear that you can run
compute-intensive HPC
applications that use
MPI/OpenMP!
– Scheduling is important
with this type of
application – as you want
all the VM to be co-

8. located to minimise
communication latency!
• General Concerns:
– Each cloud systems uses
different protocols and
different APIs… so it
may not be possible to
run applications between
cloud based systems.
– Amazon has created its
own DB system (not SQL
92), and workflow system
(many popular workflow
systems out there) – so
your normal applications
will have to be adapted to
execute on these
platforms.
The Future
• Many of the activities loosely
grouped together under cloud
computing have already been
happening and centralised
computing activity is not a new
phenomena:
• Grid Computing was the last
research-led centralised
approach.
• However there are concerns that
the mainstream adoption of cloud
computing could cause many
problems for users.
• Whether these worries are
grounded or not has yet to be
seen.
• Many new open source systems
appearing that you can install and
run on your local cluster – should
be able to run a variety of
applications on these systems.
CONCLUSION:
Finally, cloud apps don’t eat up your
valuable IT resources, so your CFO will
love it. This lets you focus on deploying
more apps, new projects, and innovation.
Cloud computing is a simple idea, but it
can have a huge impact on your business
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