Online Users

Custom Search

Categories

« first aid for poor people | Main | Differential Association theory and solution »

11/21/2011

Write a critical review


Write a critical review
Journal of Theoretical and Applied Information Technology
� 2005 - 2009 JATIT. All rights reserved.
71
CLOUD COMPUTING: AN OVERVIEW
SRINIVASA RAO V
1
NAGESWARA RAO N K
2
E KUSUMA KUMARI
3
1
PROFESSOR IN COMPUTER SCIENCE
PVP SIDDHRTHA INSTITUTE OF TECHNOLOGY
VIJAYAWADA, INDIA2
PROFESSOR& HEAD IN COMPUTER SCIENCE
PVP SIDDHRTHA INSTITUTE OF TECHNOLOGY
VIJAYAWADA, INDIA
3
ASSCIATE PROFESOR IN COMPUTER SCIENCE
NOVA COLLEGE OF ENGINEERING
JANGAREDDYGUDEM, INDIA
E-mail: akrgvsr@gmail.com
ABSTRACT
This overview gives the basic concept, defines the terms used in the industry, and outlines the general
architecture and applications of Cloud computing. It gives a summary of Cloud Computing and provides a
good foundation for understanding.
Keywords: Grid, Cloud, Computing
1. INTRODUCTION
Cloud Computing,� to put it simply, means
�Internet Computing.� The Internet is commonly
visualized as clouds; hence the term �cloud
computing� for computation done through the
Internet. With Cloud Computing users can
access database resources via the Internet from
anywhere, for as long as they need, without
worrying about any maintenance or management
of actual resources. Besides, databases in cloud
are very dynamic and scalable.
Cloud computing is unlike grid computing,
utility computing, or autonomic computing. In
fact, it is a very independent platform in terms of
computing. The best example of cloud
computing is Google Apps where any
application can be accessed using a browser and
it can be deployed on thousands of computer
through the Internet.
2. WHAT IS CLOUD COMPUTING?
Cloud computing provides the facility to access
shared resources and common infrastructure,
offering services on demand over the network to
perform operations that meet changing business
needs. The location of physical resources and
devices being accessed are typically not known
to the end user. It also provides facilities for
users to develop, deploy and manage their
applications �on the cloud�, which entails
Journal of Theoretical and Applied Information Technology
� 2005 - 2009 JATIT. All rights reserved.
72
virtualization of resources that maintains and
manages itself.
Some generic examples include:
� Amazon�s Elastic Computing Cloud (EC2)
offering computational services that enable
people to use CPU cycles without buying
more computers
� Storage services such as those provided by
Amazon�s Simple Storage Service (S3)
� Companies like Nirvanix allowing
organizations to store data and documents
without adding a single on-site server
� SaaS companies like Salesforce.com
delivering CRM services, so clients can
manage customer information without
installing specialized software
3. SOFTWARE AS A SERVICE(SAAS)
SaaS is a model of software deployment where
an application is hosted as a service provided to
customers across the Internet. Saas is generally
used to refer to business software rather than
consumer software, which falls under Web 2.0.
By removing the need to install and run an
application on a user�s own computer it is seen
as a way for businesses to get the same benefits
as commercial software with smaller cost outlay.
SaaS can alleviate the burden of software
maintenance and support but users relinquish
control over software versions and requirements.
Other terms that are used in this sphere include
Platform as a Service (PaaS) and Infrastructure
as a Service (IaaS).
4. CLOUD STORAGE
Over time many big Internet based companies
(Amazon, Google�) have come to realise that
only a small amount of their data storage
capacity is being used. This has led to the renting
Cloud Computing
Grid Computing
Journal of Theoretical and Applied Information Technology
� 2005 - 2009 JATIT. All rights reserved.
73
out of space and the storage of information on
remote servers or "clouds". Information is then
temporarily cached on desktop computers,
mobile phones or other internet-linked devices.
Amazon�s Amazon Elastic Compute Cloud
(EC2) and Simple Storage Solution (S3) are the
current best known facilities.
Data Cloud
Along with services the cloud will host data.
There has been some discussion of this being a
potentially useful notion possibly aligned with
the Semantic Web, though it could result in data
becoming undifferentiated .
5. CLOUD COMPUTING
ARCHITECTURE
Cloud computing architecture, just like any other
system, is categorized into two main sections:
Front End and Back End. Front End can be end
user or client or any application (i.e. web
browser etc.) which is using cloud services. Back
End is the network of servers with any computer
program and data storage system. It is usually
assumed that cloud contains infinite storage
capacity for any software available in market.
Cloud has different applications that are hosted
on their own dedicated server farms.
Cloud has centralized server administration
system. Centralized server administers the
system, balances client supply, adjusts demands,
monitors traffic and avoids congestion. This
server follows protocols, commonly known as
middleware. Middleware controls the
communication of cloud network among them.
Cloud Architecture runs on a very important
assumption, which is mostly true. The
assumption is that the demand for resources is
not always consistent from client to cloud.
Because of this reason the servers of cloud are
unable to run at their full capacity. To avoid this
scenario, server virtualization technique is
applied. In sever virtualization, all physical
servers are virtualized and they run multiple
servers with either same or different application.
As one physical server acts as multiple physical
servers, it curtails the need for more physical
machines.
As a matter of fact, data is the most important
part of cloud computing; thus, data security is
the top most priority in all the data operations of
cloud. Here, all the data are backed up at
multiple locations. This astoundingly increases
the data storage to multiple times in cloud
compared with a regular system. Redundancy of
data is crucial, which is a must-have attribute of
cloud computing
6. CHARACTERISTICS OF CLOUD
COMPUTING
Cloud computing, typically entails:
� High scalability
Cloud environments enable servicing of
business requirements for larger audiences,
through high scalability
� Agility
The cloud works in the �distributed mode�
environment. It shares resources among users
and tasks, while improving efficiency and
agility (responsiveness)
� High availability and reliability
Availability of servers is high and more
reliable as the chances of infrastructure
failure are minimal
Journal of Theoretical and Applied Information Technology
� 2005 - 2009 JATIT. All rights reserved.
74
� Multi-sharing
With the cloud working in a distributed and
shared mode, multiple users and applications
can work more efficiently with cost
reductions by sharing common infrastructure
� Services in pay-per-use mode
� SLAs between the provider and the user
must be defined when offering services in
pay per use mode. This may be based on
the complexity of services offered
� Application Programming Interfaces
(APIs) may be offered to the users so they
can access services on the cloud by using
these APIs
� Support for all service oriented
applications
7. COMPARISON WITH RELATED
TECHNOLOGIES
Several technologies are related to cloud
computing, and the cloud has emerged as a
convergence of several computing trends. It
seeks to address certain key aspects that may
have been lacking in each of these trends,
individually. The features of each of these
related technologies and how they compare with
cloud computing has been outlined in the table.
Types of cloud computing environments
The cloud computing environment can consist of
multiple types of clouds based on their
deployment and usage.
Public clouds
This environment can be used by the general
public. This includes individuals, corporations
and other types of organizations. Typically,
public clouds are administrated by third parties
or vendors over the Internet, and services are
offered on pay-per-use basis. These are also
called provider clouds.
Business models like SaaS (Software-as-a-
Service) and public clouds complement each
other and enable companies to leverage shared
IT resources and services.
� Example
New York Times archive project which
used 100 Amazon EC2 instances and
5.5TB of S3 storage to generate PDFs of
11 million articles for the paper�s
archives, at a small fraction of traditional
costs
� Advantages
� Public clouds are widely used in the
development, deployment and
management of enterprise
applications, at affordable costs
� Allows organizations to deliver highly
scalable and reliable applications
rapidly and at more affordable costs
� Limitations
Security is a significant concern in public
clouds
Private clouds
This cloud computing environment resides
within the boundaries of an organization and is
used exclusively for the organization�s benefits.
These are also called internal clouds. They are
built primarily by IT departments within
enterprises who seek to optimize utilization of
infrastructure resources within the enterprise by
provisioning the infrastructure with applications
using the concepts of grid and virtualization.
� Advantages
� They improve average server
utilization, allow usage of low-cost
servers and hardware while providing
higher efficiencies; thus reducing the
costs that a greater number of servers
would otherwise entail
� High levels of automation, reducing
operations costs and administrative
overheads
� Limitations
IT teams in the organization may have to
invest in buying, building and managing
the clouds independently
Journal of Theoretical and Applied Information Technology
� 2005 - 2009 JATIT. All rights reserved.
75
External clouds
This cloud computing environment is outside of
the boundaries of the organization, though it is
not necessarily a public cloud. Some external
clouds make their cloud infrastructure available
to specific other organizations, but not to the
general public.
Hybrid clouds
This is a combination of both private (internal)
and public (external) cloud computing
environments.
Variations of clouds
Clouds can be classified as:
� Infrastructures
� Platforms
� Applications
8. INFRASTRUCTURES
� Salient features
� Known also as IaaS (Infrastructure-asa-Service), acknowledged as the most
potent cloud
� Provides access to shared resources on
need basis, without revealing details
like location and hardware to clients
� Provides details like server images on
demand, storage, queuing, and
information about other resources,
among others
� Vendors who provide this type of
service enable cloud platforms and
cloud applications. Some may even
leverage others within the space to
provide competitive viability as well
� Offers full control of server
infrastructure, not limited specifically
to applications, instances and
containers
� Example
Amazon�s EC2, through which users can
request Linux Virtual Machine instances
that are created on the fly and billed based
on actual usage
� Limitations
� Service providers may demand higher
prices for services offered
� Issues pertaining to resource and
server down time
Platforms:
� Salient features
� Known also as PaaS (Platform-as-a-
Service)
� Empowers developers to deploy,
deliver and manage their applications.
They can build applications, upload
(deploy) the same into the cloud
platform and simply run and test them
� Developers can also leverage
additional benefits like authentication
and data access provided by the
platform
� This cloud takes away the concept of
servers, while providing an
application centric environment
� While creating this kind of cloud
computing platform, a vendor �builds
a cloud platform first and then
develops applications that run on it�
(OR) �develops a hostable application
and then plugs it into the cloud�. But
considering the advantages and
disadvantages, the latter would be the
better approach
� Limitations
Significant dependency on cloud
infrastructure providers
Applications:
� Salient features
Companies host applications on the
Internet and users sign up and use them,
without concerning themselves about its
Journal of Theoretical and Applied Information Technology
� 2005 - 2009 JATIT. All rights reserved.
76
maintenance and whereabouts. This is
also called as SaaS (Software-as-a-
Service)
� Advantages
Mostly free, very easy to use, featurerich,
easy to access and promises good
consumer adoption
� Limitations
User can only use the application and
would not know the technology leveraged
to develop the application; thereby user
has little control over application
development
9. CONCLUSION
After so many years, Cloud Computing today is
the beginning of �network based computing�
over Internet in force. It is the technology of the
decade and is the enabling element of two totally
new computing models, the Client-Cloud
computing and the Terminal-Cloud computing.
These new models would create whole
generations of applications and business. Our
prediction is that it is the beginning to the end of
the dominance of desktop computing such as that
with the Windows. It is also the beginning of a
new Internet based service economy: the
Internet centric, Web based, on demand, Cloud
applications and computing economy.
REFERENCES:
[1]. Software as a service, Wikipedia,

[2]. Welcome to the Data Cloud, Semantic
Web blog, ZDnet, 6 Oct 2008,

[3]. Any any any old data, Paul Walk�s blog,
7 Oct 2008,

[4]. 4 Hand, Eric. �Head in the Clouds.�
Nature. 25;449 (2007 Oct).
[5]. 5 Pollette, Chris. �How the Google-
Apple Cloud Computer Will Work.�
Howstuffworks.com. 2 Mar. 2008
.
[6]. 6 Rubel, Steve. �The MacBook Air is
the Biggest Test Yet for Cloud
Computing.� MicroPersuasion. 2 Mar.
2008
.
[7]. 7 Venezia, Paul. �Product review:
MacBook Air is light as, well, air.�
InfoWorld.com (Feb 11, 2008): NA.
General OneFile. Gale. University of
Texas at Austin. 2 Mar. 2008
.
[8]. 8 Weiss, Aaron. Computing in the
clouds. netWorker 11, 4 (Dec. 2007),
16-25
.
comments powered by Disqus

Comments

Feed You can follow this conversation by subscribing to the comment feed for this post.

The comments to this entry are closed.

Get posts by email address:

Delivered by FeedBurner








Blog powered by TypePad
Member since 09/2011