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Paper on Cloud Computing

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					Cloud computing




        By:

   Aparna Satyam

     (z1591654)
                                                          Table of Contents
CLOUD COMPUTING ................................................................................................................ 1
     TABLE OF CONTENTS.ERROR! BOOKMARK NOT DEFINED.ERROR! BOOKMARK NOT DEFINED.
1.      ABOUT CLOUD COMPUTING: ........................................................................................ 3
     DEFINITION ................................................................................................................................... 3
     HOW CLOUD COMPUTING WORKS ................................................................................................. 3
     HISTORY OF CLOUD COMPUTING [3]:............................................................................................. 3
2.      COMPARISON OF REPRESENTATIVE CLOUD PLATFORMS: .............................. 5
3.      ARCHITECTURE OF CLOUD COMPUTING: ............................................................... 5
4.      LAYERS IN CLOUD COMPUTING .................................................................................. 6
     CLIENT.......................................................................................................................................... 6
     APPLICATION ................................................................................................................................ 6
     PLATFORM .................................................................................................................................... 7
     INFRASTRUCTURE .......................................................................................................................... 7
     SERVER ......................................................................................................................................... 7
5.      FEATURES OF CLOUD COMPUTING: .......................................................................... 8
6.      ECONOMICS ........................................................................................................................ 9
7.      TYPES OF CLOUD COMPUTING MODELS ................................................................ 10
     COMMUNITY CLOUD .................................................................................................................... 10
     HYBRID CLOUD ........................................................................................................................... 10
     PRIVATE CLOUD .......................................................................................................................... 10
8.      ISSUES AND CONCERNS ................................................................................................ 11
     PRIVACY ...................................................................................................................................... 11
     COMPLIANCE .............................................................................................................................. 11
     LEGAL ..........................ERROR! BOOKMARK NOT DEFINED.ERROR! BOOKMARK NOT DEFINED.
     OPEN SOURCE ............................................................................................................................. 11
     OPEN STANDARDS ........................................................................................................................ 11
     SECURITY .................................................................................................................................... 12
9.      CRITICISM ......................................................................................................................... 12
10.         CONCLUSION ................................................................................................................ 12
11.         REFERENCES ................................................................................................................. 13
This purpose of this paper is to discuss in detail about cloud computing and its features. Target audiences
for this paper are students pursuing degree in computer science and Information system or people with
technical background who are interested to know all about cloud computing.


1. About Cloud Computing:

Definition
Cloud computing is Internet-based computing, whereby shared resources, software and
information are provided to computers and other devices on-demand, like a public utility[1].
Cloud computing customers do not own the physical infrastructure, instead avoiding capital
expenditure by renting usage from a third-party provider. They consume resources as a service
and pay only for resources that they use. A cloud computing platform dynamically provisions,
configures, reconfigures, and de-provisions servers as needed. Servers in the cloud can be
physical machines or virtual machines.
Cloud computing also describes applications that are extended to be accessible through the
Internet. These cloud applications use large data centers and powerful servers that host Web
applications and Web services. The five leading cloud contenders are– Microsoft, Salesforce,
Amazon, Google and IBM.


How Cloud Computing Works
In a cloud computing system, there's a significant workload shift. Local computers no longer
have to do all the heavy lifting when it comes to running applications. The network of computers
that make up the cloud handles them instead. Hardware and software demands on the user's side
decrease. The only thing the user's computer needs to be able to run is the cloud computing
systems interface software, which can be as simple as a Web browser, and the cloud's network
takes care of the rest.
For example, the responsibilities of an executive working in a large organization include making
sure that all the employees have the right hardware and software they need to do their jobs. This
means not only buying computers for everyone, but also hardware, software or software licenses
to give employees the tools they require. Whenever there is a new hire, he has to buy more
software or make sure the current software license allows another user.
Cloud Computing is an alternative for this stressful process. Instead of installing a suite of
software for each computer, only one application needs to be loaded. That application would
allow workers to log into a Web-based service which hosts all the programs the user would need
for his or her job. Remote machines owned by another company would run everything from e-
mail to word processing to complex data analysis programs. This is called cloud computing.

History of cloud computing [3]:
The underlying concept of cloud computing dates back to 1960, when John McCarthy said that
computation may someday be organized as a public utility. The actual term "cloud" borrows
from telephony in that telecommunications companies, who until the 1990s primarily offered
dedicated point-to-point data circuits, began offering Virtual Private Network (VPN) services
with comparable quality of service but at a much lower cost. By switching traffic to balance
utilization as they saw fit they were able to utilize their overall network bandwidth more
effectively. The cloud symbol was used to denote the demarcation point between that which was
the responsibility of the provider from that of the user. Cloud computing extends this boundary
to cover servers as well as the network infrastructure.

Cloud Computing found its origin in the success of server virtualization and the possibilities to
run IT more efficiently through server consolidation. Soon, visionaries came up with idea to
bring virtualization to a next level by implementing some early storage and network
virtualization techniques and thus making abstraction of the hardware in the entire data center.
Add to this self-provisioning and auto scaling, and Cloud Computing was born. At the time it
was called utility computing, however, and only Amazon – a bookstore – was good at it.
Amazon saw a growing popularity of its EC2 (compute) and S3 (storage) and the Amazon API
was being used by thousands of developers and many more customers to deploy and run
infrastructure in the Cloud.

The first build your own cloud (BYOC) products that were brought to the market came from
companies like Flexiscale (UK), 3Tera (US) and Q-layer (BE). They aimed at the ISP’s – who
had an urgent need for innovation: ISP’s had entered into a price war amongst themselves and
their market was now also threatened by newcomers like Amazon, Microsoft and Google. The
first new services those ISP’s offered were nothing more than virtual machines – allowing them
to run their facilities more efficiently and still charge the same prices to their customers. Soon,
companies like Savvis, GoGrid and Rackspace added interfaces that enabled end users to control
their own infrastructure. In early 2009, Sun Microsystems launched the Virtual Data Center
(VDC), a graphical interface with drag & drop that enabled users to create and manage a full
virtual data center in the cloud.
2. Comparison of representative cloud platforms:




     (Source: www.gridbus.org/papers/hpcc2008_keynote_cloudcomputing.pdf)




3. Architecture of Cloud Computing:
Cloud computing system, can be broadly divided into two sections: the front end and the back
end. The front end and the back end connect to each other through a network which we know as
Internet. The front end is the side the computer user or the client sees. The back end is the
"cloud" section of the system.

The front end includes the client's computer or the computer network and the application
required to access the cloud computing system. Not all cloud computing systems have the same
user interface. Services like Web-based e-mail programs leverage existing Web browsers like
Internet Explorer or Firefox. Other systems have unique applications that provide network access
to clients.

On the back end of the system are the various computers, servers and data storage systems that
create the "cloud” computing services. In theory, a cloud computing system could include
practically any computer program , from data processing to video games. Usually, each
application will have its own dedicated server.

A central server administers the system, monitoring traffic and client demands to ensure
everything runs smoothly. It follows a set of rules called protocols and uses a special kind of
software called middleware. Middleware allows networked computers to communicate with each
other.

A company that uses cloud computing and has lot of clients is also likely to have a high demand
for a lot of storage space. Some companies require hundreds of digital storage devices. Cloud
computing systems need at least twice the number of storage devices it requires to keep all its
clients' information stored. That's because these devices, like all computers, occasionally break
down. A cloud computing system must make a copy of all its clients' information and store it on
other devices. The copies enable the central server to access backup machines to retrieve data
that otherwise would be unreachable.


4. Layers in cloud computing
It can be safely said that cloud computing is based on five layers. The layers and their
explanation are as follows:

Client
 A cloud client consists of computer hardware and/or computer software that relies on cloud
computing for application delivery, or that is specifically designed for delivery of cloud services
and that, in either case, is essentially useless without it. Examples include some computers,
phones and other devices, operating systems and browsers.

Application
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. Key characteristics include:
   * Network-based access to, and management of, commercially available (i.e., not custom)
software

  * Activities that are managed from central locations rather than at each customer's site,
enabling customers to access applications remotely via the Web

   * Application delivery that typically is closer to a one-to-many model (single instance, multi-
tenant architecture) than to a one-to-one model, including architecture, pricing, partnering, and
management characteristics

  * Centralized feature updating, which obviates the need for downloadable patches and
upgrades.

Platform
Cloud platform services or "Platform as a Service (PaaS)" deliver a computing platform and/or
solution stack as a service, often consuming cloud infrastructure and sustaining cloud
applications. It facilitates deployment of applications without the cost and complexity of buying
and managing the underlying hardware and software layers.

Infrastructure

Cloud infrastructure services or "Infrastructure as a Service (IaaS)" delivers computer
infrastructure, typically a platform virtualization environment, as a service. Rather than
purchasing servers, software, data center space or network equipment, clients instead buy those
resources as a fully outsourced service. The service is typically billed on a utility computing
basis and amount of resources consumed (and therefore the cost) will typically reflect the level
of activity. It is an evolution of virtual private server offerings.

Server
The server 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 technology.
                               (Source: www.howstuffworks.com )




5. Features of cloud computing:
Some of the key features of cloud computing are:

* Agility improves with users' ability to rapidly and inexpensively re-provision technological
infrastructure resources.

 * Cost is claimed to be greatly reduced and capital expenditure is converted to operational
expenditure. This ostensibly lowers barriers to entry, as infrastructure is typically provided by a
third-party and does not need to be purchased for one-time or infrequent intensive computing
tasks. Pricing on a utility computing basis is fine-grained with usage-based options and fewer IT
skills are required for implementation (in-house).

  * Device and location independence enable users to access systems using a web browser
regardless of their location or what device they are using (e.g., PC, mobile). As infrastructure is
off-site (typically provided by a third-party) and accessed via the Internet, users can connect
from anywhere.

  * Multi-tenancy enables sharing of resources and costs across a large pool of users thus
allowing for:
       Centralization of infrastructure in locations with lower costs (such as real estate,
         electricity, etc.)
       Peak-load capacity increases (users need not engineer for highest possible load-levels)
       Utilization and efficiency improvements for systems that are often only 10–20%
         utilized.

  * Reliability improves through the use of multiple redundant sites, which makes cloud
computing suitable for business continuity and disaster recovery. Nonetheless, many major cloud
computing services have suffered outages, and IT and business managers can at times do little
when they are affected.

   * Scalability via dynamic ("on-demand") provisioning of resources on a fine-grained, self-
service basis near real-time, without users having to engineer for peak loads. Performance is
monitored and consistent and loosely-coupled architectures are constructed using web services as
the system interface. One of the most important new methods for overcoming performance
bottlenecks for a large class of applications is data parallel programming on a distributed data
grid.

   * Security could improve due to centralization of data, increased security-focused resources,
etc., but concerns can persist about loss of control over certain sensitive data, and the lack of
security for stored kernels. Security is often as good as or better than under traditional systems,
in part because providers are able to devote resources to solving security issues that many
customers cannot afford. Providers typically log accesses, but accessing the audit logs
themselves can be difficult or impossible. Furthermore, the complexity of security is greatly
increased when data is distributed over a wider area and / or number of devices.

   * Maintenance cloud computing applications are easier to maintain, since they don't have to
be installed on each user's computer. They are easier to support and to improve since the changes
reach the clients instantly.




6. Economics
Cloud computing users can avoid capital expenditure on hardware, software, and services when
they pay a provider only for what they use. Consumption is usually billed on a utility (resources
consumed, like electricity) or subscription (time-based, like a newspaper) basis with little or no
upfront cost. Other benefits of this time sharing-style approach are low barriers to entry, shared
infrastructure and costs, low management overhead, and immediate access to a broad range of
applications. In general, users can terminate the contract at any time (thereby avoiding return on
investment risk and uncertainty), and the services are often covered by service level agreements
(SLAs) with financial penalties. According to Nicholas Carr, the strategic importance of
information technology is diminishing as it becomes standardized and less expensive.
Although companies might be able to save on upfront capital expenditures, they might not save
much and might actually pay more for operating expenses. In situations where the capital
expense would be relatively small, or where the organization has more flexibility in their capital
budget than their operating budget, the cloud model might not make great fiscal sense. Other
factors impacting the scale of any potential cost savings include the efficiency of a company’s
data center as compared to the cloud vendor’s, the company's existing operating costs, the level
of adoption of cloud computing, and the type of functionality being hosted in the cloud.




7. Types of Cloud Computing Models
Public cloud or external cloud describes cloud computing in the traditional mainstream sense,
whereby resources are dynamically provisioned on a fine-grained, self-service basis over the
Internet, via web applications/web services, from an off-site third-party provider who shares
resources and bills on a fine-grained utility computing basis.

Community cloud
A community cloud may be established where several organizations have similar requirements
and seek to share infrastructure so as to realize some of the benefits of cloud computing. With
the costs spread over fewer users than a public cloud this option is more expensive but may offer
a higher level of privacy, security and/or policy compliance. Examples of community cloud
include Google's "Gov Cloud".

Hybrid cloud
A hybrid cloud environment consisting of multiple internal and/or external providers "will be
typical for most enterprises”. By integrating multiple cloud services users may be able to ease the
transition to public cloud services while avoiding issues such as PCI compliance.

Another perspective on deploying a web application in the cloud is using Hybrid Web Hosting,
where the hosting infrastructure is a mix between Cloud Hosting for the web server, and
Managed dedicated server for the database server.



Private cloud
Private cloud and internal cloud are neologisms that some vendors have recently used to
describe offerings that emulate cloud computing on private networks. These (typically
virtualization automation) products claim to "deliver some benefits of cloud computing without
the pitfalls", capitalizing on data security, corporate governance, and reliability concerns. They
have been criticized on the basis that users "still have to buy, build, and manage them" and as
such do not benefit from lower up-front capital costs and less hands-on management, essentially
"[lacking] the economic model that makes cloud computing such an intriguing concept".


8. Issues and Concerns

Privacy
The Cloud model has been criticized by privacy advocates for the greater ease in which the
companies hosting the Cloud services control, and thus, can monitor at will, lawfully or
unlawfully, the communication and data stored between the user and the host company.
Instances such as the secret NSA program, working with AT&T, and Verizon, which recorded
over 10 million phone calls between American citizens, causes uncertainty among privacy
advocates, and the greater powers it gives to telecommunication companies to monitor user
activity. While there have been efforts (such as US-EU Safe Harbor) to "harmonize" the legal
environment, providers such as Amazon still cater to major markets (typically the United States
and the European Union) by deploying local infrastructure and allowing customers to select
"availability zones."

Compliance
In order to obtain compliance with regulations including FISMA, HIPAA and SOX in the US,
the Data Protection Directive in the EU and the credit card industry's PCI DSS, users may have
to adopt community or hybrid deployment modes which are typically more expensive and may
offer restricted benefits. This is how Google is able to "manage and meet additional government
policy requirements beyond FISMA" and Rackspace Cloud is able to claim PCI compliance.[61]

Many providers also obtain SAS 70 Type II certification (e.g. Amazon, Google and Microsoft),
but this has been criticized on the grounds that the hand-picked set of goals and standards
determined by the auditor and the audited are often not disclosed and can vary widely. Providers
typically make this information available on request, under non-disclosure agreement.



Open source
Open standards are critical to the growth of cloud computing, and open source software has
provided the foundation for many cloud computing implementations. In November 2007, the
Free Software Foundation released the Affero General Public License, a version of GPLv3
intended to close a perceived legal loophole associated with free software designed to be run
over a network.

Open standards
Most cloud providers expose APIs which are typically well-documented (often under a Creative
Commons license) however also unique to their implementation and thus not interoperable.
Some vendors have adopted others' APIs and there are a number of open standards under
development, including the OGF's Open Cloud Computing Interface. The Open Cloud
Consortium (OCC) is working to develop consensus on early cloud computing standards and
practices.

Security
The relative security of cloud computing services is a contentious issue which may be delaying
its adoption. Some argue that customer data is more secure when managed internally, while
others argue that cloud providers have a strong incentive to maintain trust and as such employ a
higher level of security.


9. Criticism

The association of some big names of the industry such as Amazon, Salesforce, Akamai ,
Google and Yahoo with cloud computing has made people notice cloud computing and increase
their knowledge about the concept. But size and brand-name power amount to very little if a
vendor can’t deliver quality of service. Last February, Amazon S3 experienced an outage for
about three hours, leaving companies worldwide without access to their stored data. [6]

The hype surrounding cloud computing has made people believe that cloud computing is a
revolutionary new technology. But in reality, companies have been heading in the direction of
this pay-per-service model for some time now. Software-as-a-Service, for example, is a type of
cloud computing that delivers a single application through a Web-based browser to thousands of
end users. The well-known concept of utility computing also falls under the umbrella of cloud
computing, as do managed services that often entail fully outsourced network-management
arrangements.

One of the greatest myth surrounding cloud computing is that, it can solve all our server and
storage problem. But will we be comfortable in handling all our applications and data into the
hands of other. What’s more intriguing is the facts that most cloud vendors do not provide
availability assurances. Service-level agreements are mostly nonexistent. In situation like today,
it is difficult to say that cloud computing is going to achieve what its vendors are claiming.


10. Conclusion
Cloud computing is still in its early years of development. It is too early to jump into any conclusion and
make any decisions about cloud computing. Cloud Computing holds a lot of promise and I believe that it
is likely to be a major influence on hosting and application development. For the time being; we can put
things of little importance -- items of a temporary nature on the cloud and let our confidence build up. The
experience that we develop from here will let us decide which side of the cloud we are going to stay.
11. References
  1. http://en.wikipedia.org/wiki/Cloud_computing#Comparisons
  2. http://communication.howstuffworks.com/cloud-computing.htm
  3. http://download.boulder.ibm.com/ibmdl/pub/software/dw/wes/hipods/Cloud_computing_wp_fina
     l_8Oct.pdf
  4. http://www.circleid.com/posts/20090306_cloud_computing_types_public_hybrid_private/
  5. http://www.infoworld.com/d/security-central/gartner-seven-cloud-computing-security-risks-853
  6. http://www.webhostingunleashed.com/features/myths-about-cloud-computing/
  7. Cloud Computing, A Practical Approach
        by Velte, Toby; Velte, Anthony; Elsenpeter, Robert; Elsenpeter, Robert C.
  8. Dot Cloud : The 21st Century Business Platform
        by Fingar, Peter

				
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