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[[Image:Cloud computing.svg|thumb|300px|right|Cloud computing overview]]
'''Cloud computing''' refers to computing resources being accessed which are typically owned and operated by a third-party provider on a consolidated basis in Data Center locations. It is aimed at delivering supercomputer power over the internet. Consumers of cloud computing services purchase computing capacity on-demand and are not generally concerned with the underlying technologies used to achieve the increase in server capability
'''Cloud computing''' is [[Internet]] ("cloud") based development and use of computer technology ("computing").<ref>[http://www.wallstreetandtech.com/it-infrastructure/showArticle.jhtml?articleID=212700913 Cloud Computing Begins to Gain Traction on Wall Street]</ref><ref>[http://www.dirjournal.com/computers-journal/utility-based-cloud-computing-power/ Utility Based Cloud Computing Power!]</ref><ref>{{cite paper
| first        = Mark |last=Haynie
| title          = Enterprise Cloud Services: Deriving Business Value from Cloud Computing
| pages          = 13
| publisher      = Micro Focus
| url            = http://cloudservices.microfocus.com/main/uploaded/doc/MFECS-WP-deriving-business-value.pdf
| format        = [[PDF]]
| accessdate    = 2009-01-21
}}</ref> It is a style of computing in which dynamically [[scalability|scalable]] and often [[Virtualisation|virtualised]] resources are provided [[Everything as a service|as a service]] over the Internet.<ref name="really">{{cite web|url=http://www.infoworld.com/article/08/04/07/15FE-cloud-computing-reality_1.html|title=What cloud computing really means|last=Gruman|first=Galen|date=2008-04-07|work=[[InfoWorld]]|accessdate=2009-01-13}}</ref><ref>[http://portal.acm.org/citation.cfm?id=1496091.1496100&coll=&dl=ACM&CFID=21518680&CFTOKEN=18800807] A Breaks in the Clouds: towards a Cloud Definition</ref><ref>[http://www.gartner.com/it/page.jsp?id=707508 Gartner Says Cloud Computing Will Be As Influential As E-business]</ref><ref>[http://www.web2journal.com/read/612033.htm What's the difference Between Cloud Computing and SaaS?]</ref> Users need not have knowledge of, expertise in, or control over the technology infrastructure "in the cloud" that supports them<ref>[http://www.ebizq.net/blogs/saasweek/2008/03/distinguishing_cloud_computing/ Distinguishing Cloud Computing from Utility Computing]</ref>


The concept incorporates [[infrastructure as a service]] (IaaS), [[platform as a service]] (PaaS) and [[software as a service]] (SaaS) as well as [[Web 2.0]] and other recent (ca. 2007-2009)<ref name="JWilliams">{{cite web|url=http://www.johnmwillis.com/cloud-computing/who-coined-the-phrase-cloud-computing/|title=Who Coined the Phrase Cloud Computing?|last=Williams|first=John M.|coauthors=[http://twitter.com/csears Chris Sears]|date=2008-12-31|language=English|accessdate=2009-03-03}}</ref><ref name="ACampbell">{{cite web|url=http://www.theappgap.com/cloud-computing-get-used-to-the-term.html|title=Cloud Computing - Get Used to the Term|author=[http://www.theappgap.com/author/acampbell/ Anita Campbell]|date=2008-08-31|publisher=The App Gap|language=English|accessdate=2009-03-03}}</ref> technology trends which have the common theme of reliance on the Internet for satisfying the computing needs of the users. Examples of SaaS vendors include [[Salesforce.com]] and [[Google Apps]] which provide common business applications online that are accessed from a [[web browser]], while the [[software]] and [[data]] are stored on the servers.
The definition of cloud computing is very unclear. It could be defined narrowly as an updated version of utility computing: basically virtual servers available over the Internet. Others go very broad, arguing anything you consume outside the firewall is "in the cloud," including conventional outsourcing.


The term ''cloud'' is used as a metaphor for the Internet, based on how the Internet is depicted in [[computer network diagram]]s, and is an abstraction for the complex infrastructure it conceals.<ref name="The Internet Cloud">[http://www.thestandard.com/article/0,1902,5466,00.html The Internet Cloud]</ref>
The applications of cloud/utility computing models are expanding rapidly as connectivity costs fall, and as computing hardware becomes more efficient at operating at scale. The economic incentives to share hardware among multiple users are increasing; the drawbacks in performance and interactive response that used to discourage remote and distributed computing solutions are being greatly reduced. As a result, the services that can be delivered from the cloud have expanded past web applications to include storage, raw computing, or access to any number of specialized services.


==Brief==
==How does Cloud Computing Work?==
===Comparisons===
Cloud computing is often confused with [[grid computing]] ("a form of [[distributed computing]] whereby a 'super and virtual computer' is composed of a [[Cluster (computing)|cluster]] of networked, [[Loose coupling|loosely-coupled]] computers, acting in concert to perform very large tasks"), [[utility computing]] (the "packaging of [[Computational resource|computing resources]], such as computation and storage, as a metered service similar to a traditional [[public utility]] such as [[electricity]]")<ref name="It's probable that you’ve misunderstood “Cloud Computing” till now">{{cite web|url=http://portal.acm.org/citation.cfm?id=1496091.1496100&coll=&dl=ACM&CFID=21518680&CFTOKEN=18800807|title=It's probable that you’ve misunderstood 'Cloud Computing' until now|publisher=TechPluto}}</ref> and [[autonomic computing]] ("computer systems capable of [[Self-management (computer science)|self-management]]").<ref>[http://www.datacenterknowledge.com/archives/2008/Mar/25/whats_in_a_name_utility_vs_cloud_vs_grid.html What's In A Name? Utility vs. Cloud vs Grid]</ref>


Indeed many cloud computing deployments {{as of | 2009 | alt = as of 2009}} depend on [[Grid computing#Grids versus conventional supercomputers|grids]], have [[Autonomic_Computing#Autonomic_systems|autonomic]] characteristics and bill like [[utility computing|utilities]] — but cloud computing can be seen as a ''natural next step'' from the ''grid-utility model''.<ref>
Cloud computing aims to apply the power of supercomputers—measured in the tens of trillions of computations per second—to problems like analyzing risk in financial portfolios, delivering personalized medical information, even powering immersive computer games, in a way that users can tap through the Web. It does that by networking large groups of servers that often use low-cost consumer PC technology, with specialized connections to spread data-processing chores across them. The architecture behind cloud computing is a massive network of "cloud servers" interconnected as if in a grid running in parallel, sometimes using the technique of virtualization to maximize the utilization of the computing power available per server.
[http://www.nytimes.com/2007/11/15/technology/15blue.html I.B.M. to Push ‘Cloud Computing,’ Using Data From Afar]</ref> Some successful cloud architectures have little or no centralised infrastructure or billing systems whatsoever, including [[peer to peer|peer-to-peer]] networks like [[BitTorrent (protocol)|BitTorrent]] and [[Skype_Protocol#Protocol|Skype]] and [[volunteer computing]] like [[SETI@home]].<ref>[http://www.acm.org/ubiquity/volume_9/v9i31_delic.html ACM Ubiquity: Emergence of The Academic Computing Cloud]
</ref>


===Architecture===
==Advantages==
The majority of cloud computing infrastructure {{as of | 2009 | alt = as of 2009}} consists of reliable services delivered through [[data center]]s and built on servers with different levels of [[virtualization]] technologies. The services are accessible anywhere that has access to networking infrastructure. ''The Cloud'' appears as a single point of access for all the computing needs of consumers. Commercial offerings need to meet the [[quality of service]] requirements of customers and typically offer [[service level agreement]]s.<ref name="ccpaper">{{cite paper
| first        = Rajkumar |last=Buyya
|coauthors= Chee Shin Yeo, Srikumar Venugopal
| title          = Market-Oriented Cloud Computing: Vision, Hype, and Reality for Delivering IT Services as Computing Utilities
| pages          = 9
| publisher      = Department of Computer Science and Software Engineering, The University of Melbourne, Australia
| url            = http://www.gridbus.org/~raj/papers/hpcc2008_keynote_cloudcomputing.pdf
| format        = [[PDF]]
| accessdate    = 2008-07-31
}}</ref> [[Open standards]] are critical to the growth of cloud computing and [[open source software]] has provided the foundation for many cloud computing implementations.<ref>[http://www.networkworld.com/news/2008/072808-open-source-cloud-computing.html Open source fuels growth of cloud computing, software-as-a-service]</ref>


===Characteristics===
* Location of infrastructure in areas with lower costs of real estate and electricity.
As customers generally do not own the infrastructure, they merely access or rent, they can avoid [[capital expenditure]] and consume resources [[Everything as a service|as a service]], paying instead for what they use. Many cloud-computing offerings have adopted the [[utility computing]] model, which is analogous to how traditional [[Utility|utilities]] like [[electricity]] are consumed, while others are billed on a [[subscription]] basis. Sharing "perishable and intangible" computing power among [[Multitenancy|multiple tenants]] can improve utilization rates, as servers are not left idle, which can reduce costs significantly while increasing the speed of application development. A side effect of this approach is that "computer capacity rises dramatically" as customers do not have to engineer for peak loads.<ref name="wpcarney">[http://knowledge.wpcarey.asu.edu/article.cfm?articleid=1614 Cloud Computing: The Evolution of Software-as-a-Service]</ref> Adoption has been enabled by "increased high-speed bandwidth" which makes it possible to receive the same response times from centralized infrastructure at other sites.
* Sharing of peak-load capacity among a large pool of users, improving overall utilization.
* Separation of infrastructure maintenance duties from domain-specific application development.
* Separation of application code from physical resources.
* Ability to use external assets to handle peak loads (not having to engineer for highest possible load levels).
* Not having to purchase assets for one-time or infrequent intensive computing tasks.
* Ability to scale to meet changing user demands quickly, usually within minutes


===Economics===
==Challenges facing cloud computing==
[[Image:Cloud computing economics.svg|thumb|right|250px]]
Cloud computing users can avoid [[capital expenditure]] (CapEx) on hardware, software and services, rather paying a provider only for what they use. Consumption is billed on a [[utility computing|utility]] (e.g. resources consumed, like electricity) or [[subscription]] (e.g. 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. Users can generally terminate the contract at any time (thereby avoiding [[return on investment]] risk and uncertainty) and the services are often covered by [[service level agreement]]s with financial penalties.<ref>[http://www.eweek.com/c/a/Enterprise-Applications/Forresters-Advice-to-CFOs-Embrace-Cloud-Computing-to-Cut-Costs/ Forrester's Advice to CFOs: Embrace Cloud Computing to Cut Costs]</ref><ref>[http://www.networkworld.com/columnists/2008/080508-dzubeck.html Five cloud computing questions]</ref>


According to [[Nicholas Carr]] the strategic importance of [[information technology]] is diminishing as it becomes standardised and cheaper. He argues that the cloud computing [[paradigm shift]] is similar to the displacement of [[electricity generator]]s by [[electricity grid]]s early in the 20th century.<ref>[http://www.computerworlduk.com/technology/internet/applications/instant-expert/index.cfm?articleid=1610 Nicholas Carr on 'The Big Switch' to cloud computing]</ref>
The technical standards for connecting the various computer systems and pieces of software needed to make cloud computing work still aren't completely defined. That could slow progress on new products. Without high-speed connections—especially wireless ones—cloud computing services won't be widely accessible. And storing large amounts of data about users' identity and preferences is likely to raise new concerns about privacy protection.


===Companies===
==Cloud Storage==
<!-- This section is intended to illustrate the types of companies getting involved -->
<!-- It should have 3 or 4 at most examples, and these should be the best for the category -->
<!-- It's NOT an authorative list - for this refer to the categories and/or lists -->
<!-- DO NOT ADD COMPANIES HERE THAT THE GENERAL PUBLIC DOES NOT ALREADY ASSOCIATE WITH CLOUD COMPUTING -->


Providers including [[Amazon Web Services|Amazon]], [[Google]] and [[Yahoo]] exemplify the use of cloud computing<ref>[http://www.infoage.idg.com.au/index.php/id;909486215;fp;4;fpid;1051515815 What is cloud computing?]</ref>. It is being adopted by individual users through large enterprises including [[General Electric]], [[L'Oréal]], and [[Procter & Gamble]].<ref>[http://www.computerweekly.com/Articles/2008/06/24/231178/google-apps-makes-its-way-into-big-business.htm Google Apps makes its way into big business]</ref><ref>[http://seekingalpha.com/article/85608-google-inc-q2-2008-earnings-call-transcript Google, Inc. Q2 2008 Earnings Call]</ref>
Cloud storage is a model of networked data storage where data is stored on multiple virtual servers, generally hosted by third parties, rather than being hosted on dedicated servers. Hosting companies operate large data centers; and people who require their data to be hosted buy or lease storage capacity from them and use it for their storage needs. The data center operators, in the background, virtualize the resources according to the requirements of the customer and expose them as virtual servers, which the customers can themselves manage. Physically, the resource may span across multiple servers. In some services, such as Nirvanix, the system may span multiple data centers or even continents.


==History==
==Examples==
''The Cloud'' is a term with a long history in telephony, which has in the past decade, been adopted as a metaphor for internet based services, with a common depiction in [[network diagram]]s as a cloud outline.<ref name="The Internet Cloud"/>


The underlying concept dates back to [[1960]] when [[John McCarthy (computer scientist)|John McCarthy]] opined that "computation may someday be organized as a [[public utility]]"; indeed it shares characteristics with [[service bureau]]s which date back to the 1960s. The term ''cloud'' had already come into commercial use in the early 1990s to refer to large ATM networks.<ref>[http://mirror.switch.ch/ftp/doc/ietf/ipatm/atm-minutes-93jul.txt July, 1993 meeting report from the IP over ATM working group of the IETF]</ref> By the turn of the 21st century, the term "cloud computing" had started to appear,<ref>[http://www.nytimes.com/2001/04/09/technology/09HAIL.html?ex=1217563200&en=7c46bdefb6a8450a&ei=5070 Internet Critic Takes on Microsoft]</ref> although most of the focus at this time was on [[Software as a service]] (SaaS).
* IBM’s Blue cloud
 
* Amazon Elastic Compute Cloud
In 1999, [[Salesforce.com]] was established by [[Marc Benioff]], Parker Harris, and his fellows. They applied many technologies of consumer web sites like Google and [[Yahoo!]] to business applications. They also provided the concept of "On demand" and "SaaS" with their real business and successful customers.  The key for SaaS is being customizable by customer alone or with a small amount of help. Flexibility and speed for application development have been drastically welcomed and accepted by business users.
* Microsoft Live Mesh
 
* Apple Mobile Me
[[IBM]] extended these concepts in 2001, as detailed in the Autonomic Computing Manifesto [http://www.research.ibm.com/autonomic/index.html] -- which described advanced automation techniques such as self-monitoring, self-healing, self-configuring, and self-optimizing in the management of complex IT systems with heterogeneous storage, servers, applications, networks, security mechanisms, and other system elements that can be virtualized across an enterprise.
 
[[Amazon.com]] played a key role in the development of cloud computing by modernizing their [[data centre]]s after the [[dot-com bubble]] and, having found that the new cloud architecture resulted in significant internal efficiency improvements, providing access to their systems by way of [[Amazon Web Services]] in [[2002]] on a [[utility computing]] basis.<ref name="amazon">[http://www.businessweek.com/magazine/content/06_46/b4009001.htm Jeff Bezos' Risky Bet]
</ref>
 
[[2007]] saw increased activity, with [[Google]], [[IBM]], and a number of universities embarking on a large scale ''cloud computing'' research project,<ref>[http://www.nytimes.com/2007/10/08/technology/08cloud.html?_r=1&ex=1349496000&en=92627f0f65ea0d75&ei=5090&partner=rssuserland&emc=rss&oref=slogin Google and I.B.M. Join in ‘Cloud Computing’ Research]</ref> around the time the term started gaining popularity in the mainstream press. It was a hot topic by mid-2008 and numerous cloud computing events had been scheduled.<ref>[http://www.networkworld.com/newsletters/itlead/2008/070708itlead1.html Keep an eye on cloud computing]</ref>
 
In [[August 2008]], [[Gartner Research]] observed that "organizations are switching from company-owned hardware and software assets to per-use service-based models" and that the "projected shift to cloud computing will result in dramatic growth in IT products in some areas and in significant reductions in other areas."<ref>[http://www.gartner.com/it/page.jsp?id=742913 Gartner Says Worldwide IT Spending On Pace to Surpass $3.4 Trillion in 2008]
</ref>
 
== Political issues ==
''The Cloud'' spans many borders and "may be the ultimate form of globalization."<ref name="cwb">[http://www.economist.com/specialreports/displaystory.cfm?story_id=12411854 Computers without borders]</ref> As such it becomes subject to complex [[geopolitics|geopolitical]] issues: providers must satisfy myriad regulatory environments in order to deliver service to a global market. This dates back to the early days of the Internet, where libertarian thinkers felt that "cyberspace was a distinct place calling for laws and legal institutions of its own"; author [[Neal Stephenson]] envisaged this as a tiny island data haven called [[Kinakuta]] in his classic science-fiction novel [[Cryptonomicon]].<ref name="cwb" />
 
Despite efforts (such as [[US-EU Safe Harbor]]) to harmonise the legal environment, providers like [[Amazon Web Services]] cater {{as of | 2009 | alt = as of 2009}} to the major markets (typically the [[United States]] and the [[European Union]]) by deploying local infrastructure and allowing customers to select "availability zones."<ref>[http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1347&categoryID=112 Feature Guide: Amazon EC2 Availability Zones]</ref> Nonetheless, there are still concerns about security and privacy from individual through governmental level, e.g., the [[USA PATRIOT Act]] and use of [[national security letter]]s and the [[Electronic Communications Privacy Act]]'s ''Stored Communications Act''.
 
== Legal issues ==
In March 2007, [[Dell]] applied to [[trademark]] the term "cloud computing" ({{US trademark|77139082}}) in the [[United States]]. The "Notice of Allowance" it received in July 2008 was canceled on [[August 6]], resulting in a formal rejection of the trademark application less than a week later.
 
On 30 September 2008, [[USPTO]] issued a "Notice of Allowance" to CGactive LLC ({{US trademark|77355287}}) for "CloudOS". A ''cloud operating system'' is a [[genericized trademark|generic]] [[operating system]] that "manage[s] the relationship between software inside the computer and on the Web", such as [[Microsoft Azure]]<ref>[http://www.nytimes.com/2008/10/28/technology/28soft.html Microsoft Plans ‘Cloud’ Operating System]</ref>. Good OS LLC also announced their
"[[Cloud (operating system)|Cloud]]" operating system on 1 December 2008<ref>[http://www.thinkgos.com/company/pr20081201.html Good OS Announces Cloud — A New Operating System for 2009]</ref>.
 
[[Richard Stallman]], founder of the [[Free Software Foundation]], believes that cloud computing endangers liberties because users sacrifice their privacy and personal data to a third party.<ref>[http://www.guardian.co.uk/technology/2008/sep/29/cloud.computing.richard.stallman/ Cloud computing is a trap, warns GNU founder Richard Stallman, Guardian, September 30, 2008]</ref> In November 2007, the [[Free Software Foundation]] released the [[Affero General Public License]], a version of [[GNU General Public License|GPLv3]] designed to close a perceived [[Legal technicality|legal loophole]] associated with [[Free software]] designed to be run over a network, particularly [[software as a service]].  An [[application service provider]] is required to release any changes they make to Affero GPL [[open source]] code.
 
==Risk mitigation==
{{undue|section}}
Corporations or end-users wishing to avoid losing or not being able to access their data should research vendors' policies on data security before using vendor services.  The technology analyst and consulting firm, [[Gartner]], lists seven security issues which one should discuss with a cloud-computing vendor:
# Privileged user access—inquire about who has specialized access to data and about the hiring and management of such administrators
# Regulatory compliance—make sure a vendor is willing to undergo external audits and/or security certifications 
# Data location—ask if a provider allows for any control over the location of data
# Data segregation—make sure that encryption is available at all stages and that these "encryption schemes were designed and tested by experienced professionals"
# Recovery—find out what will happen to data in the case of a disaster; do they offer complete restoration and, if so, how long that would take
# Investigative Support—inquire as to whether a vendor has the ability to investigate any inappropriate or illegal activity
# Long-term viability—ask what will happen to data if the company goes out of business; how will data be returned and in what format<ref>Brodkin, Jon. "Gartner: Seven cloud-computing security risks | InfoWorld | News | 2008-07-02 |  ." InfoWorld - Business technology, IT news, product reviews and enterprise IT strategies. 3 Dec. 2008 <http://www.infoworld.com/article/08/07/02/Gartner_Seven_cloudcomputing_security_risks_1.html>.</ref>
 
In practice, one can best determine data-recovery capabilities by experiment: asking to get back old data, seeing how long it takes, and verifying that the checksums match the original data. Determining data security is harder. A tactic not covered by Gartner is to encrypt the data yourself. If you encrypt the data using a trusted algorithm, then regardless of the service provider's security and encryption policies, the data will only be accessible with the decryption keys. This leads to a follow-on problem: managing private keys in a pay-on-demand computing infrastructure.
 
== Key characteristics ==
<!-- Pros and Cons are discussed as 'key characteristics' as each typically has both -->
<!-- Separate pros and cons lists are very confusing, with the same topics, e.g., security, listed in both -->
 
* '''[[Cost]]''' is greatly reduced and [[capital expenditure|CapEx]] is converted to [[operational expenditure|OpEx]]<ref>[http://www.cloudave.com/link/recession-is-good-for-cloud-computing-microsoft-agrees Recession Is Good For Cloud Computing – Microsoft Agrees]</ref>. This 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 minimal or no IT skills are required for implementation.<ref name="idc">[http://blogs.idc.com/ie/?p=190 Defining “Cloud Services” and “Cloud Computing”]</ref>
* '''[[Device independence|Device]] and location independence'''<ref name="yarmis">[http://news.cnet.com/8301-13953_3-9977049-80.html The new geek chic: Data centers]</ref> 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 the users can connect from anywhere.<ref name="idc" />
* '''[[Multitenancy|Multi-tenancy]]''' enables sharing of resources and costs among a large pool of users, allowing for:
** '''Centralization''' of infrastructure in areas with lower costs (such as real estate, electricity, etc.)
** '''Peak-load capacity''' increases (users need not engineer for highest possible load-levels)
** '''Utilisation and efficiency''' improvements for systems that are often only 10-20% utilised.<ref name="amazon"/>
* '''[[Reliability]]''' improves through the use of multiple redundant sites, which makes it suitable for [[business continuity]] and [[disaster recovery]].<ref>[http://www.data-storage-today.com/news/Cloud-Computing--Firms-Take-Flight/story.xhtml?story_id=0130012A6383 Cloud Computing: Small Companies Take Flight]</ref> Nonetheless, most major cloud computing services have suffered outages and IT and business managers are able to do little when they are affected.<ref>[http://www.pcworld.com/businesscenter/article/149892/google_apps_admins_jittery_about_gmail_hopeful_about_future.html Google Apps Admins Jittery About Gmail, Hopeful About Future]</ref><ref name="cloudfeud">[http://www.datacenterknowledge.com/archives/2008/09/22/a-new-resource-born-of-a-cloud-feud/A New Resource, Born of a Cloud Feud]</ref>
* '''[[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. [[Computer performance|Performance]] is monitored and consistent and loosely-coupled architectures are constructed using [[web services]] as the system interface.<ref name="idc" />
* '''[[Computer security|Security]]''' typically improves due to centralization of data,<ref>[http://exari.blogspot.com/2006/05/death-by-laptop.html Exari: Death By Laptop]</ref> increased security-focused resources, etc., but raises concerns about loss of control over certain sensitive data. Security is often as good as or better than traditional systems, in part because providers are able to devote resources to solving security issues that many customers cannot afford<ref>[http://news.cnet.com/8301-1009_3-10150569-83.html Cloud computing security forecast: Clear skies]</ref>. Providers typically log accesses, but accessing the [[audit log]]s themselves can be difficult or impossible.
* '''[[Sustainability]]''' comes about through improved resource utilisation, more efficient systems, and [[carbon neutrality]].<ref>[http://news.zdnet.co.uk/internet/0,1000000097,39287634,00.htm Google to go carbon neutral by 2008]</ref><ref>[http://jobsearchtech.about.com/od/historyoftechindustry/a/cloud_computing.htm What is Cloud Computing?]</ref> Nonetheless, computers and associated infrastructure are major consumers of energy.<ref>[http://www.time.com/time/specials/2007/environment/article/0,28804,1602354_1603074_1603535,00.html Shut off your computer]</ref>
 
==Components==
[[Image:CloudComputingStackLarge.svg|250px|right]]
===Application===
 
A ''cloud application'' leverages the Cloud in [[software architecture]], often eliminating the need to install and run the application on the customer's own computer, thus alleviating the burden of software maintenance, ongoing operation, and support. For example:
* [[Peer-to-peer]] / [[volunteer computing]] ([[Bittorrent]], [[List of distributed computing projects#Berkeley Open Infrastructure for Network Computing (BOINC)|BOINC Projects]], [[Skype]])
* [[Web application]] ([[Facebook]])
* [[Software as a service]] ([[Google Apps]], [[SAP Business ByDesign|SAP]] and [[Salesforce]])
* [[Software plus services]] ([[Microsoft Online Services]])
<!-- Please DO NOT list insignificant or poor examples here -->
<!-- These lists are intended for clarity, not confusion, nor to be comprehensive -->
<!-- Consider instead using the associated category -->
 
===Client===
 
A ''cloud client'' consists of [[computer hardware]] and/or [[computer software]] which relies on [[The Cloud]] for application delivery, or which is specifically designed for delivery of cloud services and which, in either case, is essentially useless without it.<ref name="nimbus"/> For example:
 
* [[Mobile computing|Mobile]] ([[Android (mobile device platform)|Android]], [[iPhone]], [[Windows Mobile]])<ref>[http://www.wired.com/techbiz/media/magazine/16-07/ff_android?currentPage=all Google's Open Source Android OS Will Free the Wireless Web]</ref><ref>[http://www.nytimes.com/2008/07/17/technology/personaltech/17pogue.html?_r=1&oref=slogin In Sync to Pierce the Cloud]</ref><ref>[http://www.windowsfordevices.com/news/NS6388605875.html Microsoft demos mobile cloud sync client]</ref>
 
* [[Thin client]] ([[CherryPal]], [[Zonbu]], [[gOS (operating system)|gOS]]-based systems)<ref>[http://www.itbusinessedge.com/blogs/hdw/?p=2626 CherryPal brings cloud computing to the masses]</ref><ref>[http://www.newsobserver.com/business/technology/gilster/2007/story/771924.html Zonbu has alluring features, price]</ref><ref>[http://www.businesswire.com/portal/site/home/index.jsp?epi_menuItemID=887566059a3aedb6efaaa9e27a808a0c&ndmViewId=news_view&ndmConfigId=1009040&newsId=20080103005831&newsLang=en GOS cloud computing]</ref>
 
* [[Thick client]] / [[Web browser]] ([[Google Chrome]],<ref>[http://www.eweek.com/index.php?option=content&task=view&id=49417 Google Chrome Aims to Break Microsoft Windows]</ref> [[Mozilla Firefox]])
<!-- Please DO NOT list insignificant or poor examples here -->
<!-- These lists are intended for clarity, not confusion, nor to be comprehensive -->
<!-- Consider instead using the associated category -->
 
===Infrastructure===
 
''Cloud infrastructure'', such as [[Infrastructure as a service]], is the delivery of [[computer]] [[infrastructure]], typically a [[platform virtualization]] environment, [[Everything as a service|as a service]].<ref>[http://searchstorage.techtarget.com/news/article/0,289142,sid5_gci1301852,00.html EMC buys Pi and forms a cloud computing group]</ref> For example:
* [[Full virtualization]] ([[GoGrid]], [[Skytap]])
* [[Grid computing]] ([[Sun Grid]])
* Management ([[RightScale]])
* [[Compute]] ([[Amazon Elastic Compute Cloud]])
* Platform ([[Force.com]])
<!-- Please DO NOT list insignificant or poor examples here -->
<!-- These lists are intended for clarity, not confusion, nor to be comprehensive -->
<!-- Consider instead using the associated category -->
 
===Platform===
 
A ''cloud platform'', such as [[Platform as a service]], the delivery of a [[computing platform]], and/or [[solution stack]] [[Everything as a service|as a service]], facilitates deployment of applications without the cost and complexity of buying and managing the underlying hardware and software layers.<ref>[http://www.guardian.co.uk/technology/2008/apr/17/google.software Google angles for business users with 'platform as a service']</ref> For example:
* [[Web application framework]]s
** [[Ajax]] ([[Caspio]])
** [[Python (programming language)|Python]] [[Django (web framework)|Django]] ([[Google App Engine]])
** [[Ruby on Rails]] ([[Heroku]])
* [[Web hosting]] ([[Mosso (web host)|Mosso]], [[Clustered Cloud]])
* Proprietary ([[Azure Services Platform|Azure]], [[Salesforce|Force.com]])
<!-- Please DO NOT list insignificant or poor examples here -->
<!-- These lists are intended for clarity, not confusion, nor to be comprehensive -->
<!-- Consider instead using the associated category -->
 
===Service===
 
A ''cloud service'' includes "products, services and solutions that are delivered and consumed in real-time over the Internet"<ref name="idc" />. For example, [[Web Service]]s ("software system[s] designed to support [[interoperability|interoperable]] [[Machine to Machine|machine-to-machine]] interaction over a [[computer network|network]]")<ref>{{cite web |url=http://www.w3.org/TR/ws-gloss/ |title=Web Services Glossary}}</ref> which may be accessed by other cloud computing components, software, e.g., [[Software plus services]], or end users directly.<ref>[http://aws.typepad.com/aws/2008/06/the-forthcoming.html The Emerging Cloud Service Architecture]</ref> Specific examples include:
* [[Identity]] ([[OAuth]], [[OpenID]])
* [[Integration]] ([[Amazon Simple Queue Service]])
* [[Payment]]s ([[Amazon Flexible Payments Service]], [[Google Checkout]], [[PayPal]])
* [[Web mapping|Mapping]] ([[Google Maps]], [[Yahoo! Maps]])
* [[Web search engine|Search]] ([[Alexa Internet|Alexa]], [[Google Custom Search]], [[Yahoo! Search BOSS|Yahoo! BOSS]])
* Others ([[Amazon Mechanical Turk]])
<!-- Please DO NOT list insignificant or poor examples here -->
<!-- These lists are intended for clarity, not confusion, nor to be comprehensive -->
<!-- Consider instead using the associated category -->
 
===Storage===
 
''Cloud storage'' involves the delivery of [[Computer data storage|data storage]] [[Everything as a service|as a service]], including database-like services, often billed on a [[utility computing]] basis, e.g., per [[gigabyte]] per month.<ref>[http://arstechnica.com/news.ars/post/20070812-google-microsoft-and-apple-building-online-storage-havens-you-win.html Google, Microsoft and Apple building online storage havens: you win]</ref> For example:
<!-- Given Akamai is known as an EDN/CDN, listing them here confuses rather than clarifies -->
<!-- If their NetStorage offering is sufficiently notable, it should have its own article -->
<!-- which can be listed here, if it is relevant -->
<!-- * [[Akamai_Technologies]] Inc. [http://www.akamai.com/html/technology/products/netstorage.html NetStorage] -->
* [[Database]] ([[Amazon SimpleDB]], [[Google App Engine]]'s [[BigTable]] datastore)
* [[Network attached storage]] ([[MobileMe]] [[iDisk]], [[Nirvanix]] CloudNAS)
* [[Synchronisation]] ([[Live Mesh]] ''Live Desktop'' component, [[MobileMe]] [[Push technology|push]] functions)
* [[Web service]] ([[Amazon Simple Storage Service]], [[Nirvanix]] SDN)
<!-- Please DO NOT list insignificant or poor examples here -->
<!-- These lists are intended for clarity, not confusion, nor to be comprehensive -->
<!-- Consider instead using the associated category -->
 
== Architecture ==
[[Image:CloudComputingSampleArchitecture.svg|400px|right]]
 
''Cloud architecture'',<ref>[http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1632&categoryID=100 Building GrepTheWeb in the Cloud, Part 1: Cloud Architectures ]</ref> the [[systems architecture]] of the [[software systems]] involved in the delivery of ''cloud computing'', comprises hardware and software designed by a ''cloud architect''<!-- circular definition? --> who typically works for a ''cloud integrator''. It typically involves multiple ''cloud components'' communicating with each other over [[application programming interface]]s, usually [[web service]]s.<ref>[http://blogs.forrester.com/it_infrastructure/2008/07/cloud-maturity.html Cloud Maturity Is Accelerating: More Than Just Reaction To The Hype?]</ref>
 
This closely resembles the [[Unix philosophy]] of having multiple programs doing one thing well and working together over universal interfaces. Complexity is controlled and the resulting systems are more manageable than their [[Monolithic system|monolithic]] counterparts.
 
''Cloud architecture'' extends to the client, where [[web browser]]s and/or [[software application]]s access ''cloud applications''.
 
''Cloud storage architecture'' is loosely coupled, where [[metadata]] operations are centralized enabling the data nodes to scale into the hundreds, each independently delivering data to applications or users.
 
== Types ==
[[Image:Cloud computing types.svg|thumb|350px|right|Cloud computing types]]
=== Public cloud ===
''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 application]]s/[[web service]]s, from an off-site third-party provider who [[multitenancy|shares resources]] and bills on a fine-grained [[utility computing]] basis.<ref>[http://blogs.idc.com/ie/?p=190 Defining “Cloud Services” and “Cloud Computing”]</ref>
 
=== Hybrid cloud ===
A ''hybrid cloud'' environment consisting of multiple internal and/or external providers<ref>[http://www.businessinsider.com/2009/2/ibm-embraces-juniper-for-its-smart-hybrid-cloud-disses-cisco-ibm IBM Embraces Juniper For Its Smart 'Hybrid Cloud', Disses Cisco (IBM)]</ref> "will be typical for most enterprises".<ref name="iwpc" />
 
=== 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 [[platform virtualization|virtualisation]] [[automation]]) products claim to "deliver some benefits of cloud computing without the pitfalls", capitalising on data security, corporate governance, and reliability concerns. They have been criticised 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<ref name="iwpc">[http://www.informationweek.com/news/services/business/showArticle.jhtml?articleID=209904474 Private Clouds Take Shape]</ref>, essentially "[lacking] the economic model that makes cloud computing such an intriguing concept".<ref>[http://news.cnet.com/8301-13556_3-10150841-61.html Just don't call them private clouds]</ref><ref>[http://www.informationweek.com/cloud-computing/blog/archives/2009/01/theres_no_such.html There's No Such Thing As A Private Cloud]</ref>
 
While an analyst predicted in 2008 that private cloud networks would be the future of corporate IT,<ref>[http://www.networkworld.com/news/2008/111208-private-cloud-networks.html Private cloud networks are the future of corporate IT]</ref> there is some contention as to whether they are a reality even within the same firm.<ref>[http://blogs.gartner.com/nick_gall/2009/02/09/private-cloud-computing-the-only-thing-real-so-far-is-the-desire/ Private Cloud Computing: The Only Thing Real so Far is the Desire]</ref> Analysts also claim that within five years a "huge percentage" of [[small and medium enterprises]] will get most of their computing resources from external cloud computing providers as they "will not have economies of scale to make it worth staying in the IT business" or be able to afford private clouds.<ref>[http://www.informationweek.com/cloud-computing/blog/archives/2009/01/milliondollar_p.html Million-Dollar Private Clouds]</ref>
 
The term has also been used in the logical rather than physical sense, for example in reference to [[platform as a service]] offerings.<ref>[http://www.theregister.co.uk/2008/04/08/google_unveils_app_engine/ Google opens private cloud to coders]</ref>
 
== Roles ==
=== Provider ===
 
A ''cloud computing provider'' or ''cloud computing service provider'' owns and operates live ''cloud computing'' systems to deliver service to third parties. Usually this requires significant resources and expertise in building and managing next-generation [[data center]]s. Some organisations realise a subset of the benefits of cloud computing by becoming "internal" cloud providers and servicing themselves, although they do not benefit from the same economies of scale and still have to engineer for peak loads. The [[barrier to entry]] is also significantly higher with [[capital expenditure]] required and billing and management creates some [[overhead]]. Nonetheless, significant operational efficiency and agility advantages can be realised, even by small organisations, and server consolidation and virtualization rollouts are already well underway.<ref>[http://www.acmqueue.org/modules.php?name=Content&pa=showpage&pid=528 ACM Queue - Beyond Server Consolidation]</ref> [[Amazon.com]] was the first such provider, modernising its [[data center]]s which, like most [[computer networks]], were using as little as 10% of its capacity at any one time just to leave room for occasional spikes. This allowed small, fast-moving groups to add new features faster and easier, and they went on to open it up to outsiders as [[Amazon Web Services]] in [[2002]] on a [[utility computing]] basis.<ref name="amazon"/>
 
The companies listed in the ''Components'' section are providers.
 
=== User ===
{{Cat see also|Cloud computing users}}
 
A user is a consumer of ''cloud computing''.<ref name="nimbus">[http://workspace.globus.org/vm/TP2.1/doc/cloud.html Nimbus Cloud Guide]</ref> The privacy of users in cloud computing has become of increasing concern.<ref>
[http://knol.google.com/k/carl-hewitt/orgs-for-scalable-robust-privacy/pcxtp4rx7g1t/6# ORGs for Scalable, Robust, Privacy-Friendly Client Cloud Computing]</ref><ref>[http://blog.wired.com/27bstroke6/2008/08/google-privacy.html Google Privacy Practices Worse Than ISP Snooping, AT&T Charges]</ref> The rights of users is also an issue, which is being addressed via a community effort to create a [[bill of rights]].<ref>The bill of rights is [http://wiki.cloudcommunity.org/wiki/CloudComputing:Bill_of_Rights currently in draft].</ref><ref>[http://saas.sys-con.com/read/filter/saaslatest.htm Draft Cloud Computing: Bill of Rights Now Available]</ref><ref>{{cite web|url=http://wiki.cloudcommunity.org/wiki/CloudComputing:Bill_of_Rights|title=Cloud Computing:Bill of rights|last=Johnston|first=Sam|coauthors=Urquhart, James; Wellner, Rich|date=2008-09-16|accessdate=2008-09-16}}</ref>
 
=== Vendor ===
 
A vendor sells products and services that facilitate the delivery, adoption and use of ''cloud computing''.<ref>[http://groups.google.ca/group/cloud-computing/web/list-of-cloud-platforms-providers-and-enablers List of Cloud Platforms, Providers and Enablers]
</ref> For example:
 
* [[Computer hardware]] ([[Dell]], [[Hewlett Packard|HP]], [[IBM]], [[Sun Microsystems]])
** [[Computer storage|Storage]] ([[Sun Microsystems]], [[EMC]], [[IBM]])
** Infrastructure ([[Cisco Systems]])
* [[Computer software]] ([[3tera]], [[Hadoop]], [[IBM]], [[RightScale]])
** [[Operating system]]s ([[Solaris (operating system)|Solaris]], [[AIX]], [[Linux]] including [[Red Hat]]<ref>[http://resources.zdnet.co.uk/articles/features/0,1000002000,39454819,00.htm Red Hat chief: 'The clouds will all run Linux']</ref>)
** [[Platform virtualization]] ([[Citrix]], [[Microsoft]], [[VMware]], [[Sun xVM]], [[IBM]])
Other providers such as Reviora combine behind the scenes technologies to deliver software-as-a-service to customers.
 
== Standards ==
 
''Cloud standards'', a number of existing, typically lightweight, [[open standard]]s, have facilitated the growth of cloud computing, including:<ref>[http://redmonk.com/sogrady/2008/06/24/cloud_standards/ The Cloud and Standards]</ref>
* '''Application'''
** [[Communication]]s ([[HTTP]], [[XMPP]])
** [[Security]] ([[OAuth]], [[OpenID]], [[Secure Sockets Layer|SSL]]/[[Transport Layer Security|TLS]]<ref>[http://searchsoa.techtarget.com/news/article/0,289142,sid26_gci1328293,00.html Lock-in, security loom as dark side of Compute Cloud]</ref>)
** [[Web syndication|Syndication]] ([[Atom (standard)|Atom]])
* '''Client'''
** [[Web browser|Browser]]s ([[AJAX]])
** [[Online and offline|Offline]] ([[HTML 5]])
* '''Implementations'''
** [[Platform virtualization|Virtualization]] ([[Open Virtualization Format|OVF]]<ref>[http://searchdatacenter.techtarget.com/news/article/0,289142,sid80_gci1324347,00.html LinuxWorld/Next Generation Data Center attendees get schooled in cloud computing]</ref>)
* '''Platform'''
** [[Solution stack]]s ([[LAMP (software bundle)|LAMP]])
* '''Service'''
** [[Data]] ([[XML]], [[JSON]])
** [[Web Services]] ([[Representational State Transfer|REST]])
* '''Storage'''
<!-- ** [[XAM]] -->


==References==
==References==
{{reflist|2}}
<ref name="Computing Heads for Clouds">{{Cite web|url=http://www.businessweek.com/technology/content/nov2007/tc20071116_379585.htm|title=Computing Heads for Clouds|accessdate=2008-07-22}}</ref>
 
<ref name="What cloud computing really means">{{Cite web|url=http://www.infoworld.com/article/08/04/07/15FE-cloud-computing-reality_1.html|title=What cloud computing really means|accessdate=2008-07-22}}</ref>
[[Category:Cloud computing]]
<references/>
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Revision as of 15:35, 11 March 2009

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Cloud computing refers to computing resources being accessed which are typically owned and operated by a third-party provider on a consolidated basis in Data Center locations. It is aimed at delivering supercomputer power over the internet. Consumers of cloud computing services purchase computing capacity on-demand and are not generally concerned with the underlying technologies used to achieve the increase in server capability

The definition of cloud computing is very unclear. It could be defined narrowly as an updated version of utility computing: basically virtual servers available over the Internet. Others go very broad, arguing anything you consume outside the firewall is "in the cloud," including conventional outsourcing.

The applications of cloud/utility computing models are expanding rapidly as connectivity costs fall, and as computing hardware becomes more efficient at operating at scale. The economic incentives to share hardware among multiple users are increasing; the drawbacks in performance and interactive response that used to discourage remote and distributed computing solutions are being greatly reduced. As a result, the services that can be delivered from the cloud have expanded past web applications to include storage, raw computing, or access to any number of specialized services.

How does Cloud Computing Work?

Cloud computing aims to apply the power of supercomputers—measured in the tens of trillions of computations per second—to problems like analyzing risk in financial portfolios, delivering personalized medical information, even powering immersive computer games, in a way that users can tap through the Web. It does that by networking large groups of servers that often use low-cost consumer PC technology, with specialized connections to spread data-processing chores across them. The architecture behind cloud computing is a massive network of "cloud servers" interconnected as if in a grid running in parallel, sometimes using the technique of virtualization to maximize the utilization of the computing power available per server.

Advantages

  • Location of infrastructure in areas with lower costs of real estate and electricity.
  • Sharing of peak-load capacity among a large pool of users, improving overall utilization.
  • Separation of infrastructure maintenance duties from domain-specific application development.
  • Separation of application code from physical resources.
  • Ability to use external assets to handle peak loads (not having to engineer for highest possible load levels).
  • Not having to purchase assets for one-time or infrequent intensive computing tasks.
  • Ability to scale to meet changing user demands quickly, usually within minutes

Challenges facing cloud computing

The technical standards for connecting the various computer systems and pieces of software needed to make cloud computing work still aren't completely defined. That could slow progress on new products. Without high-speed connections—especially wireless ones—cloud computing services won't be widely accessible. And storing large amounts of data about users' identity and preferences is likely to raise new concerns about privacy protection.

Cloud Storage

Cloud storage is a model of networked data storage where data is stored on multiple virtual servers, generally hosted by third parties, rather than being hosted on dedicated servers. Hosting companies operate large data centers; and people who require their data to be hosted buy or lease storage capacity from them and use it for their storage needs. The data center operators, in the background, virtualize the resources according to the requirements of the customer and expose them as virtual servers, which the customers can themselves manage. Physically, the resource may span across multiple servers. In some services, such as Nirvanix, the system may span multiple data centers or even continents.

Examples

  • IBM’s Blue cloud
  • Amazon Elastic Compute Cloud
  • Microsoft Live Mesh
  • Apple Mobile Me

References

[1] [2]

  1. Computing Heads for Clouds. Retrieved on 2008-07-22.
  2. What cloud computing really means. Retrieved on 2008-07-22.