Difference between revisions of "Cloud computing"

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[[File:Cloud computing.svg|400px|thumb|Cloud computing logical diagram]]
[[File:Cloud computing.svg|400px|thumb|Cloud computing logical diagram]]
''Cloud computing''' is the delivery of computing as a service rather than a product, whereby shared resources, software and [[information]] are provided to computers and other devices as a utility (like the electricity grid) over a network (typically the Internet).
'''Cloud computing''' is the delivery of computing as a service rather than a product, whereby shared resources, software, and [[information]] are provided to computers and other devices as a utility (like the electricity grid) over a network, typically the Internet.
 
Cloud computing describes a new supplement, consumption, and delivery model for IT services based on Internet protocols, and it typically involves provisioning of dynamically scalable and often virtualized resources<ref name="GartnerCC">{{cite web |url=http://www.gartner.com/newsroom/id/707508 |archiveurl=https://web.archive.org/web/20180828134416/https://www.gartner.com/newsroom/id/707508 |title=Gartner Says Cloud Computing Will Be As Influential As E-business |publisher=Gartner, Inc |date=26 June 2008 |archivedate=28 August 2018 |accessdate=14 April 2020}}</ref><ref name="GrumanReally">{{cite web |url=https://www.infoworld.com/article/2683784/what-is-cloud-computing.html |title=What is cloud computing? Everything you need to know now |author=Knorr, E. |work=InfoWorld |publisher=IDG Network |date=02 October 2018 |accessdate=14 April 2020}}</ref> Details are abstracted from end-users, who no longer have need for expertise in, or control over, the technology infrastructure "in the cloud" that supports them.<ref name="Danielson">{{cite web |url=http://www.ebizq.net/blogs/saasweek/2008/03/distinguishing_cloud_computing/ |archiveurl=https://web.archive.org/web/20200124141938/http://www.ebizq.net/blogs/saasweek/2008/03/distinguishing_cloud_computing/ |title=Distinguishing Cloud Computing from Utility Computing |author=Danielson, K. |work=ebizQ |publisher=TechTarget |date=26 March 2008 |archivedate=24 January 2020 |accessdate=07 January 2022}}</ref>
 
Cloud computing typically takes the form of web-based tools or applications that users can access and use through a web browser as if they were programs installed locally on their own computers. Those applications and resulting data are stored on servers at a remote location. In some cases, legacy applications (line of business applications that until now have been prevalent in thin client Windows computing) are delivered via a screen-sharing technology, while the computing resources are consolidated at a remote data center location; in other cases, entire business applications have been coded using web-based technologies such as [[Ajax]].


==Overview==
==Overview==
Cloud computing provides computation, software, data access, and storage services that do not require end-user knowledge of the physical location and configuration of the system that delivers the services. Parallels to this concept can be drawn with the electricity grid, wherein end-users consume power without needing to understand the component devices or infrastructure required to provide the service.<!-- per consensus on talk page: http://en.wikipedia.org/w/index.php?title=Talk:Cloud_computing&oldid=349182637#The_lead.27s_first_sentence -->
===Term===
The term "cloud" is used as a metaphor for the Internet, based on the cloud drawing used in the past to represent the telephone network,<ref name="TAPI">{{cite web |url=http://www.sellsbrothers.com/writing/intro2tapi/default.aspx?content=pstn.htm |archiveurl=https://web.archive.org/web/20050502192319/http://www.sellsbrothers.com/writing/intro2tapi/default.aspx?content=pstn.htm |title=Windows Telephony Programming: A Developer's Guide to TAPI |author=Sells, Chris |work=Sellsbrothers.com |date=01 July 1998 |archivedate=02 May 2005 |accessdate=21 August 2014}}</ref> and later to depict the Internet in computer network diagrams as an abstraction of the underlying infrastructure it represents.<ref name="ScanlonCloud">{{cite web |archiveurl=https://web.archive.org/web/20100211133442/http://www.thestandard.com/article/0,1902,5466,00.html |url=http://www.thestandard.com/article/0,1902,5466,00.html |title=The Internet Cloud |author=Scanlon,Jessie Holliday; Wieners, Brad |work=The Industry Standard |publisher=IDG Network |date=09 July 1999 |archivedate=11 February 2010 |accessdate=2010-08-22}}</ref>


The concept of cloud computing fills a perpetual need of IT:  a way to increase capacity or add capabilities on the fly without investing in new infrastructure, training new personnel, or licensing new software. Cloud computing encompasses any subscription-based or pay-per-use service that, in real time over the Internet, extends IT's existing capabilities.{{Citation needed|date=August 2011}}
===Characteristics===
The National Institute of Standards and Technology (NIST) offers an authoritative definition of cloud computing. That definition encompasses the essential characteristics, service models, and deployment models of the service. Of the essential characteristics, cloud computing must<ref name="NISTCloudDef">{{cite web |url=https://csrc.nist.gov/publications/detail/sp/800-145/final |title=The NIST Definition of Cloud Computing |author=Mell, P.; Grance, T. |publisher=National Institute of Standards and Technology |date=September 2011 |accessdate=14 April 2020}}</ref>:


Cloud computing describes a new supplement, consumption, and delivery model for IT services based on Internet protocols, and it typically involves provisioning of dynamically scalable and often virtualized resources<ref name="gartner">{{Cite web|url=http://www.gartner.com/it/page.jsp?id=707508 |title=Gartner Says Cloud Computing Will Be As Influential As E-business |publisher=Gartner.com |date= |accessdate=2010-08-22}}</ref><ref name="really">{{Cite web|url=http://www.infoworld.com/d/cloud-computing/what-cloud-computing-really-means-031|title=What cloud computing really means|last=Gruman|first=Galen|date=2008-04-07|work=InfoWorld|accessdate=2009-06-02}}</ref> It is a byproduct and consequence of the ease-of-access to remote computing sites provided by the Internet.<ref>{{Cite news|url=http://www.economist.com/displaystory.cfm?story_id=14637206|title=Cloud Computing: Clash of the clouds|date=2009-10-15|publisher=The Economist|accessdate=2009-11-03}}</ref> This may take the form of web-based tools or applications that users can access and use through a web browser as if they were programs installed locally on their own computers.<ref name="simple">[http://www.cloudcomputingdefined.com/ Cloud Computing Defined] 17 July 2010. Retrieved 26 July 2010.</ref>
* provide computing capabilities and services on an as-needed basis, without human intervention;
* be broadly accessible from a wide variety of standard desktop and mobile platforms;
* make storage, processing, memory, and network bandwidth available as pooled, multi-tenant resources;
* make those resources scalable with demand, often automatically, at any time; and
* meter those resources and make the resulting information transparently available to both provider and consumer.


Cloud computing providers deliver applications via the internet, which are accessed from a Web browser, while the business software and data are stored on servers at a remote location.  In some cases, legacy applications (line of business applications that until now have been prevalent in thin client Windows computing) are delivered via a screen-sharing technology, while the computing resources are consolidated at a remote data center location; in other cases, entire business applications have been coded using web-based technologies such as AJAX.
Additional, more granular characteristics of cloud computing include the following.


Most cloud computing infrastructures consist of services delivered through shared data-centers and appearing as a single point of access for consumers' computing needs. Commercial offerings may be required to meet service level agreements (SLAs), but specific terms are less often negotiated by smaller companies.<ref name="ccpaper">{{Cite journal
* An application programming interface (API) enables machines to interact with cloud software in the same way the user interface facilitates interaction between humans and computers. Cloud computing systems typically use REST-based APIs.
|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, University of Melbourne, Australia| url            = http://www.gridBus.org/~raj/papers/hpcc2008_keynote_cloudcomputing.pdf
| format = PDF| accessdate    = 2008-07-31}}</ref>


===Comparisons===
* Cost is potentially reduced in a public cloud delivery model, with capital expenditure being converted to operational expenditure, including research, development, and sales.<ref name="ColumbusMaking">{{cite web |url=https://www.forbes.com/sites/louiscolumbus/2013/04/10/making-cloud-computing-pay-2/ |title=Making Cloud Computing Pay |author=Columbus, L. |publisher=Forbes |date=10 April 2013 |accessdate=14 April 2020}}</ref> This is purported to lower 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 in-house IT skills are required for implementation.<ref name="GensCloud">{{cite web |url=http://blogs.idc.com/ie/?p=190 |archiveurl=https://web.archive.org/web/20170528125047/http://blogs.idc.com/ie/?p=190 |title=Defining "Cloud Services" and "Cloud Computing" |author=Gens, Frank |publisher=IDC |date=23 September 2008 |archivedate=28 May 2017 |accessdate=14 April 2020}}</ref>
<!-- this need not enumerate every different type of computing, just the top half-dozen that are provably linked to cloud computing -->
Cloud computing shares characteristics with:


* Autonomic computing — Computer systems capable of self-management."<ref>{{Cite web|url=http://www.datacenterknowledge.com/archives/2008/Mar/25/whats_in_a_name_utility_vs_cloud_vs_grid.html |title=What's In A Name? Utility vs. Cloud vs Grid |publisher=Datacenterknowledge.com |date= |accessdate=2010-08-22}}</ref>
* 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 phone).<ref name="FarberData">{{cite web |url=https://www.cnet.com/news/the-new-geek-chic-data-centers/ |title=The new geek chic: Data centers |author=Farber, D. |work=CNET |publisher=CBS Interactive |date=25 June 2008 |accessdate=14 April 2020}}</ref> As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet, users can connect from anywhere.<ref name="GensCloud" />
* Client–server model — ''Client–Server Computing'' refers broadly to any [[distributed application]] that distinguishes between service providers (servers) and service requesters (clients).<ref>{{Cite web|url=http://java.sun.com/developer/Books/jdbc/ch07.pdf|publisher=Sun Microsystem|title=Distributed Application Architecture|accessdate=2009-06-16}}</ref>
* Grid computing — "A form of [[distributed computing]] and [[parallel computing]], whereby a 'super and virtual computer' is composed of a cluster of networked, loosely coupled computers acting in concert to perform very large tasks."
* Mainframe computer — Powerful computers used mainly by large organizations for critical applications, typically bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.<ref>{{Cite web|url=http://itknowledgeexchange.techtarget.com/mainframe-blog/sun-cto-cloud-computing-is-like-the-mainframe/ |title=Sun CTO: Cloud computing is like the mainframe |publisher=Itknowledgeexchange.techtarget.com |date=2009-03-11 |accessdate=2010-08-22}}</ref>
* Utility computing — The "packaging of computing resources, such as computation and storage, as a metered service similar to a traditional public utility, such as electricity."<ref name="It's you've ">{{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 |accessdate=2010-09-14}}</ref>
* Peer-to-peer — Distributed architecture without the need for central coordination, with participants being at the same time both suppliers and consumers of resources (in contrast to the traditional client–server model).
* Service-oriented computing –  Cloud computing provides services related to computing while, in a reciprocal manner, service-oriented computing consists of the computing techniques that operate on software-as-a-service.<ref name="Service-oriented Computing and Cloud Computing: Challenges and Opportunities">{{Cite web|url=http://www.computer.org/portal/web/csdl/doi/10.1109/MIC.2010.147|title=Service-Oriented Computing and Cloud Computing: Challenges and Opportunities | publisher= IEEE Internet Computing |accessdate=2010-12-04}}</ref>


===Characteristics===
* Multi-tenancy enables sharing of resources and costs across a large pool of users, allowing for centralization of infrastructure in locations with lower costs, peak-load capacity increases, and utilization and efficiency improvements.
 
* Reliability is improved if multiple redundant sites are used, which makes well-designed cloud computing suitable for business continuity and disaster recovery.<ref name="KingCloud">{{cite web |url=https://www.bloomberg.com/news/articles/2008-08-04/cloud-computing-small-companies-take-flightbusinessweek-business-news-stock-market-and-financial-advice |title=Cloud Computing: Small Companies Take Flight |author=King, R. |publisher=Bloomberg |date=04 August 2008 |accessdate=14 April 2020}}</ref>


<!-- Pros and Cons are discussed as 'key features' as each typically has both -->
* Services are scalable and elastic via dynamic, "on-demand" provisioning of resources on a fine-grained, self-service basis in real-time, without users having to engineer for peak loads.<ref name="Kuperberg">{{cite web |url=https://publikationen.bibliothek.kit.edu/1000023476 |title=Defining and Quantifying Elasticity of Resources in Cloud Computing and Scalable Platforms |author=Kuperberg, M.; Herbst, N.;  von Kistowski, J.; Reussner, R. |publisher=Karlsruher Institut für Technologie |date=2011 |accessdate=14 April 2020}}</ref>
<!-- Separate pros and cons lists are very confusing, with the same topics, e.g., security, listed in both -->
Cloud computing exhibits the following key characteristics:
* '''Agility''' improves with users' ability to re-provision technological infrastructure resources.
* '''Application Programming Interface''' (API) accessibility to software that enables machines to interact with cloud software in the same way the user interface facilitates interaction between humans and computers.  Cloud computing systems typically use REST-based APIs.
* '''Cost''' is claimed to be reduced and in a public cloud delivery model capital expenditure is converted to operational expenditure.<ref>{{Cite web|url=http://www.cloudave.com/link/recession-is-good-for-cloud-computing-microsoft-agrees |title=Recession Is Good For Cloud Computing – Microsoft Agrees |publisher=CloudAve |date= |accessdate=2010-08-22}}</ref> This is purported to lower 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).<ref name="idc">{{Cite web|url=http://blogs.idc.com/ie/?p=190 |title=Defining "Cloud Services" and "Cloud Computing" |publisher=IDC |date=2008-09-23 |accessdate=2010-08-22}}</ref>
* '''Device and location independence'''<ref name="yarmis">{{Cite web|last=Farber |first=Dan |url=http://news.cnet.com/8301-13953_3-9977049-80.html |title=The new geek chic: Data centers |publisher=CNET News |date=2008-06-25 |accessdate=2010-08-22}}</ref> enable users to access systems using a web browser regardless of their location or what device they are using (e.g., PC, mobile phone). As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet, users can connect from anywhere.<ref name="idc" />
* '''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.<ref name="amazon"/>
* '''Reliability''' is improved if multiple redundant sites are used, which makes well-designed cloud computing suitable for [[business continuity]] and [[disaster recovery]].<ref>{{Cite web|last=King |first=Rachael |url=http://www.businessweek.com/technology/content/aug2008/tc2008083_619516.htm |title=Cloud Computing: Small Companies Take Flight |publisher=Businessweek |date=2008-08-04 |accessdate=2010-08-22}}</ref>
* '''Scalability'''  and Elasticity 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. <ref>{{cite web|title=Defining and Measuring Cloud Elasticity|url=http://digbib.ubka.uni-karlsruhe.de/volltexte/1000023476|publisher=KIT Software Quality Departement|accessdate=13 August 2011}}</ref>
* '''Performance''' is monitored, and consistent and loosely coupled architectures are constructed using web services as the system interface.<ref name="idc" />
* '''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.<ref>{{Cite web|url=http://www.cryptoclarity.com/CryptoClarityLLC/Welcome/Entries/2009/7/23_Encrypted_Storage_and_Key_Management_for_the_cloud.html |title=Encrypted Storage and Key Management for the cloud |publisher=Cryptoclarity.com |date=2009-07-30 |accessdate=2010-08-22}}</ref> 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.<ref>{{Cite web|last=Mills |first=Elinor |url=http://news.cnet.com/8301-1009_3-10150569-83.html |title=Cloud computing security forecast: Clear skies |publisher=CNET News |date=2009-01-27 |accessdate=2010-08-22}}</ref> However, the complexity of security is greatly increased when data is distributed over a wider area or greater number of devices and in multi-tenant systems that are being shared by unrelated users. In addition, user access to security [[audit log]]s may be difficult or impossible. Private cloud installations are in part motivated by users' desire to retain control over the infrastructure and avoid losing control of information security.
* '''Maintenance''' of cloud computing applications is easier, because they do not need to be installed on each user's computer. They are easier to support and to improve, as the changes reach the clients instantly.


===Architecture===
* Performance is monitored, and consistent and loosely coupled architectures are constructed using web services as the system interface.<ref name="GensCloud" />
[[File:CloudComputingSampleArchitecture.svg|thumb|325px|right|Cloud computing sample architecture]]


''Cloud architecture'',<ref>{{Cite web|url=http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1632&categoryID=100 |title=Building GrepTheWeb in the Cloud, Part 1: Cloud Architectures |publisher=Developer.amazonwebservices.com |date= |accessdate=2010-08-22}}</ref> the systems architecture of the software systems involved in the delivery of cloud computing, typically involves multiple ''cloud components'' communicating with each other over loose coupling mechanism such as messaging queue.
* Security could improve due to centralization of data, increased security-focused resources, etc., but concerns may persist about loss of control over certain sensitive data and the lack of security for stored kernels.


==History==
* Maintenance of cloud computing applications is easier, because they do not need to be installed on each user's computer. They are easier to support and to improve, as the changes reach the clients instantly.
The term "cloud" is used as a metaphor for the Internet, based on the cloud drawing used in the past to represent the telephone network,<ref>{{Cite web|url=http://www.sellsbrothers.com/writing/intro2tapi/default.aspx?content=pstn.htm |title=Writing & Speaking |publisher=Sellsbrothers.com |date= |accessdate=2010-08-22}}</ref> and later to depict the Internet in computer network diagrams as an abstraction of the underlying infrastructure it represents.<ref>{{Cite web|url=http://www.thestandard.com/article/0,1902,5466,00.html |title=The Internet Cloud |publisher=Thestandard.com |date= |accessdate=2010-08-22}}</ref>


Cloud computing is a natural evolution of the widespread adoption of virtualization, service-oriented architecture, autonomic, and utility computing. Details are abstracted from end-users, who no longer have need for expertise in, or control over, the technology infrastructure "in the cloud" that supports them.<ref>{{Cite web|last=Danielson |first=Krissi |url=http://www.ebizq.net/blogs/saasweek/2008/03/distinguishing_cloud_computing/ |title=Distinguishing Cloud Computing from Utility Computing |publisher=Ebizq.net |date=2008-03-26 |accessdate=2010-08-22}}</ref>
===Service models===
The NIST definition also details the service models, which include [[software as a service]] (SaaS; provider's application runs on their infrastructure), platform as a service (PaaS; consumer-created or -acquired application runs on provider's infrastructure), and infrastructure as a service (IaaS; customer deploys operating systems and applications over fundamental computing resources provisioned by the provider).<ref name="NISTCloudDef" />


The underlying concept of cloud computing dates back to the 1960s, when John McCarthy opined that "computation may someday be organized as a [[public utility]]." Almost all the modern-day characteristics of cloud computing (elastic provision, provided as a utility, online, illusion of infinite supply), the comparison to the electricity industry and the use of public, private, government, and community forms, were thoroughly explored in Douglas Parkhill's 1966 book, ''The Challenge of the Computer Utility''.
====SaaS====
NIST's definition of cloud computing defines SaaS as<ref name="NISTCloudDef" />:


The actual term "cloud" borrows from telephony in that telecommunications companies, who until the 1990s offered primarily 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 and that which was the responsibility of the user.  Cloud computing extends this boundary to cover servers as well as the network infrastructure.<ref>{{Cite web|url=http://mirror.switch.ch/ftp/doc/ietf/ipatm/atm-minutes-93jul.txt |title=July, 1993 meeting report from the IP over ATM working group of the IETF |date= |accessdate=2010-08-22}}</ref>
<blockquote>The capability provided to the consumer is to use the provider's applications running on a cloud infrastructure. The applications are accessible from various client devices through either a thin client interface, such as a web browser (e.g., web-based email), or a program interface. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings.</blockquote>


After the dot-com bubble, Amazon played a key role in the development of cloud computing by modernizing their data centers, which, like most computer networks, were using as little as 10% of their capacity at any one time, just to leave room for occasional spikes.  Having found that the new cloud architecture resulted in significant internal efficiency improvements whereby small, fast-moving "two-pizza teams" could add new features faster and more easily, Amazon initiated a new product development effort to provide cloud computing to external customers, and launched Amazon Web Service (AWS) on a utility computing basis in 2006.<ref name="amazon">[http://www.businessweek.com/magazine/content/06_46/b4009001.htm Jeff Bezos' Risky Bet].</ref><ref name="AWS">[http://itknowledgeexchange.techtarget.com/cloud-computing/2010/06/17/amazons-early-efforts-at-cloud-computing-partly-accidental/].</ref>
By not needing to manage the cloud infrastructure and platform where the application runs, the need to install and run the application on the cloud user's own computers is eliminated, simplifying maintenance and support. The pricing model for SaaS applications is typically a monthly or yearly flat fee per user, and as such prices become scalable and adjustable if users are added or removed at any point.


In early 2008, Eucalyptus became the first open-source, AWS API-compatible platform for deploying private clouds. In early 2008, OpenNebula, enhanced in the RESERVOIR European Commission-funded project, became the first open-source software for deploying private and hybrid clouds, and for the federation of clouds.<ref>B. Rochwerger, J. Caceres, R.S. Montero, D. Breitgand, E. Elmroth, A. Galis, E. Levy, I.M. Llorente, K. Nagin, Y. Wolfsthal,  E. Elmroth, J. Caceres, M. Ben-Yehuda, W. Emmerich, F. Galan. "The RESERVOIR Model and Architecture for Open Federated Cloud Computing", IBM Journal of Research and Development, Vol. 53, No. 4. (2009)</ref> In the same year, efforts were focused on providing QoS guarantees (as required by real-time interactive applications) to cloud-based infrastructures, in the framework of the IRMOS European Commission-funded project.<ref>D. Kyriazis, A. Menychtas, G. Kousiouris, K. Oberle, T. Voith, M. Boniface, E. Oliveros, T. Cucinotta, S. Berger, “A Real-time Service Oriented Infrastructure”, International Conference on Real-Time and Embedded Systems (RTES 2010), Singapore, November 2010</ref> By mid-2008, Gartner saw an opportunity for cloud computing "to shape the relationship among consumers of IT services, those who use IT services and those who sell them"<ref>[http://www.networkworld.com/newsletters/itlead/2008/070708itlead1.html Keep an eye on cloud computing], Amy Schurr, Network World, 2008-07-08, citing the Gartner report, "Cloud Computing Confusion Leads to Opportunity". Retrieved 2009-09-11.</ref> and observed that "organisations are switching from company-owned hardware and software assets to per-use service-based models" so that the "projected shift to cloud computing ... will result in dramatic growth in IT products in some areas and significant reductions in other areas."<ref>[http://www.gartner.com/it/page.jsp?id=742913 Gartner Says Worldwide IT Spending On Pace to Surpass  Trillion in 2008], Gartner, 2008-08-18. Retrieved 2009-09-11.</ref>
Proponents of this model claim that SaaS has the potential to reduce IT operational costs by outsourcing hardware and software maintenance and support to the cloud provider. This enables the business to reallocate IT operations costs away from hardware/software spending and from personnel expenses, towards meeting other goals. In addition, with applications hosted centrally, updates can be released without the need for users to install new software.<ref name="GriffinInternet18">{{cite book |url=https://books.google.com/books?id=OuTEDwAAQBAJ&pg=PA111 |title=Internet Governance |author=Griffin, R. |publisher=ED-Tech Press |pages=111–13 |year=2018 |isbn=9781839473951 |accessdate=14 April 2020}}</ref>


==Layers==
====PaaS====
Once an Internet Protocol connection is established among several computers, it is possible to share services within any one of the following layers.
NIST's definition of cloud computing defines PaaS as<ref name="NISTCloudDef" />:
<!-- we could shrink this were it not for WP's dodgy renderer - may update the source instead -->
[[File:Cloud Computing Stack.svg|right|250px]]


===Client===
<blockquote>The capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages, libraries, services, and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly configuration settings for the application-hosting environment.</blockquote>
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]], phones and other devices, [[operating systems]], and [[Internet browser|browsers]].<ref>{{Cite web|last=Claburn |first=Thomas |url=http://www.informationweek.com/news/software/web_services/showArticle.jhtml?articleID=222200331 |title=Google Reveals Nexus One 'Super Phone' |publisher=InformationWeek |date= |accessdate=2010-08-22}}</ref><ref>{{Cite web|url=http://gigaom.com/2008/06/22/what-makes-a-good-cloud-computer/ |title=What Makes a Cloud Computer? |publisher=Gigaom.com |date=2008-06-22 |accessdate=2010-08-22}}</ref><ref>{{Cite web|author=by Brian BraikerSeptember 02, 2008 |url=http://www.newsweek.com/id/156911 |title=The Cloud's Chrome Lining |publisher=Newsweek.com |date=2008-09-02 |accessdate=2010-08-22}}</ref>


===Application===
As such, PaaS users do not manage or control the underlying cloud infrastructure, including network, servers, operating systems, or storage. Rather, they have control over the deployed applications, and in some cases the configuration settings for the application-hosting environment.<ref name="GriffinInternet18" />
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===
====IaaS====
Cloud platform services, also known as [[Platform as a service|Platform as a Service]] (PaaS), deliver a computing platform and/or solution stack as a service, often consuming cloud infrastructure and sustaining cloud applications.<ref>{{Cite web|url=http://www.eccentex.com/platform/workflow.html |title=An example of a 'Cloud Platform' for building applications |publisher=Eccentex.com |date= |accessdate=2010-08-22}}</ref> It facilitates deployment of applications without the cost and complexity of buying and managing the underlying hardware and software layers.<ref>{{Cite news|author=Jack Schofield |url=http://www.guardian.co.uk/technology/2008/apr/17/google.software |title=Google angles for business users with 'platform as a service' |publisher=Guardian |date= 2008-04-17|accessdate=2010-08-22 | location=London}}</ref><ref>{{Cite web|url=http://aws.typepad.com/aws/2008/06/the-forthcoming.html |title=The Emerging Cloud Service Architecture |publisher=Aws.typepad.com |date=2008-06-03 |accessdate=2010-08-22}}</ref>
NIST's definition of cloud computing describes IaaS as a platform "where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, and deployed applications, and possibly limited control of select networking components (e.g., host firewalls)."<ref name="NISTCloudDef" />


===Infrastructure===
IaaS-cloud providers supply these resources on-demand from their large pools of equipment installed in data centers. For wide area network connectivity, customers can use either the internet or carrier clouds (dedicated virtual private networks). To deploy their applications, cloud users install operating-system images and their application software on the cloud infrastructure. The cloud user patches and maintains the operating systems and the application software on the infrastructure. Cloud providers typically bill IaaS services on a utility computing basis: cost reflects the amount of resources allocated and consumed.<ref name="GriffinInternet18" />
Cloud infrastructure services, also known as Infrastructure as a Service (IaaS), deliver computer [[infrastructure]] – typically a platform virtualization 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.<ref>{{Cite web|url=http://searchstorage.techtarget.com/news/article/0,289142,sid5_gci1301852,00.html |title=EMC buys Pi and forms a cloud computing group |publisher=Searchstorage.techtarget.com |date=2008-02-21 |accessdate=2010-08-22}}</ref>


===Server===
===Deployment models===
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.<ref name="nimbus">[http://workspace.globus.org/vm/TP2.1/doc/cloud.html Nimbus Cloud Guide]{{Dead link|date=August 2010}}</ref><ref>{{Cite web|last=Myslewski |first=Rik |url=http://www.theregister.co.uk/2009/12/02/intel_scc/ |title=Intel puts cloud on single megachip |publisher=Theregister.co.uk |date=2009-12-02 |accessdate=2010-08-22}}</ref><ref>{{Cite web|last=Duffy |first=Jim |url=http://www.infoworld.com/d/cloud-computing/cisco-unveils-cloud-computing-platform-service-providers-113 |title=Cisco unveils cloud computing platform for service providers |publisher=Infoworld.com |date=2009-05-12 |accessdate=2010-08-22}}</ref><ref>[http://www.nytimes.com/2008/10/28/technology/28soft.html Microsoft Plans 'Cloud' Operating System]</ref>
[[File:Cloud_computing_types.svg|thumb|325px|right|Cloud computing deployment types]]
The NIST definition identifies four deployment models for cloud computing.<ref name="NISTCloudDef" />


==Deployment models==
''Private cloud'': an infrastructure operated solely for a single organization, whether managed internally or by a third-party and hosted internally or externally
<!-- TODO: find source & add community cloud -->
[[File:Cloud computing types.svg|thumb|395px|right|Cloud computing types]]


===Public cloud===
''Community cloud'': an infrastructure shared between several organisations from a specific community with common concerns (security, compliance, jurisdiction, etc.), managed internally or by a third-party and hosted internally or externally
Public cloud describes cloud computing in the traditional mainstream sense, whereby resources are dynamically provisioned to the general public on a fine-grained, self-service basis over the Internet, via web applications/web services, from an off-site third-party provider who bills on a fine-grained utility computing basis.<ref name="idc"/>


===Community cloud===
''Public cloud'': an infrastructure where resources are dynamically provisioned to the general public on a fine-grained, self-service basis over the Internet, via web applications/web services, from an off-site third-party provider who bills on a metered basis
Community cloud shares infrastructure between several organisations from a specific community with common concerns (security, compliance, jurisdiction, etc.), whether managed internally or by a third-party and hosted internally or externally. The costs are spread over fewer users than a public cloud (but more than a private cloud), so only some of the benefits of cloud computing are realised.<ref name=nist />


===Hybrid cloud ===
''Hybrid cloud'': a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together, offering the benefits of multiple deployment models
Hybrid cloud is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together, offering the benefits of multiple deployment models.<ref name=nist>{{cite web|title=The NIST Definition of  Cloud Computing (Draft)|url=http://csrc.nist.gov/publications/drafts/800-145/Draft-SP-800-145_cloud-definition.pdf|publisher=National Institute of Science and Technology|accessdate=24 July 2011}}</ref>


===Private cloud===
Other deployment options have arisen as well. Another (potentially classifiable as "hybrid") that has become more notable is [[carrier cloud]], cloud computing services integrated into a communications service provider's network infrastructure.<ref name="KontronWP">{{cite web |url=https://www.kontron.com/resources/collateral/white_papers/kontroncarriercloudwp.pdf |format=PDF |title=Cloud Evolution: The Carrier Cloud |publisher=Kontron |date=2013 |accesssdate=14 April 2020}}</ref><ref name="NarcisiCC">{{cite web |url=https://searchnetworking.techtarget.com/feature/Carrier-cloud-services-Do-customers-care-if-you-own-the-network |archiveurl=https://web.archive.org/web/20190624173258/https://searchnetworking.techtarget.com/feature/Carrier-cloud-services-Do-customers-care-if-you-own-the-network |title=Carrier cloud services: Do customers care if you own the network? |author=Narcisi, G. |work=SearchNetworking |publisher=TechTarget |date=November 2013 |archivedate=24 June 2019 |accessdate=07 January 2022}}</ref> Others include distributed cloud (a distributed set of machines in different locations)<ref name="CunsoloVolunteer09">{{cite journal |title=Volunteer Computing and Desktop Cloud: The Cloud@Home Paradigm |journal=2009 Eighth IEEE International Symposium on Network Computing and Applications |author=Cunsolo, V.D.; Distefano, S.; Puliafito, A. et al. |pages=134–9 |year=2009 |doi=10.1109/NCA.2009.41}}</ref>, high-performance computing cloud (able to handle [[high-performance computing]] applications)<ref name="NettoHPC18">{{cite journal |title=HPC Cloud for Scientific and Business Applications: Taxonomy, Vision, and Research Challenges |journal=AMC Computing Surveys |author=Netto, M.A.S.; Calheiros, R.N.; Rodrigues, E.R. et al. |volume=51 |issue=1 |at=8 |year=2018 |doi=10.1145/3150224}}</ref>, and polycloud (use of multiple public clouds from different providers, levaraging specific services each offers).<ref name="GallPoly18">{{cite web |url=https://hub.packtpub.com/polycloud-a-better-alternative-to-cloud-agnosticism/ |title=Polycloud: A better alternative to cloud agnosticism |author=Gall, R. |work=Cloud and Networking News |publisher=Packt Publishing |date=16 May 2018 |accessdate=14 April 2020}}</ref>
Private cloud is infrastructure operated solely for a single organisation, whether managed internally or by a third-party and hosted internally or externally.<ref name=nist />


They have attracted criticism because users "still have to buy, build, and manage them" and thus do not benefit from lower up-front capital costs and less hands-on management,<ref name="iwpc">{{Cite web|last=Foley |first=John |url=http://www.informationweek.com/news/services/business/showArticle.jhtml?articleID=209904474 |title=Private Clouds Take Shape |publisher=InformationWeek |date= |accessdate=2010-08-22}}
==History==
</ref>
The underlying concept of cloud computing dates back to the 1960s, when John McCarthy opined that "computation may someday be organized as a public utility."<ref name="HalpertAuditing">{{cite book |url=https://books.google.com/books?id=GjsH0HJ2PmYC&pg=PT10&lpg=PT10 |chapter=Chapter 1: Introduction to Cloud Computing |title=Auditing Cloud Computing: A Security and Privacy Guide |author=Halpert, Ben |publisher=John Wiley & Sons |pages=1–13 |year=2011 |isbn=9781118116043 |accessdate=07 January 2022}}</ref> Almost all the modern-day characteristics of cloud computing (elastic provision, provided as a utility, online, illusion of infinite supply), as well as the comparison to the electricity industry and the use of public, private, government, and community forms, were thoroughly explored in Douglas Parkhill's 1966 book, ''The Challenge of the Computer Utility''.<ref name="ParkhillChall">{{cite book |url=https://books.google.com/books?id=8kJZAAAAMAAJ |title=The Challenge of the Computer Utility |author=Parhill, Douglas |publisher=Addison-Wesley Pub. Co |year=2006 |accessdate=07 January 2022}}</ref>
essentially "[lacking] the economic model that makes cloud computing such an intriguing concept".<ref>
{{Cite web|last=Haff |first=Gordon |url=http://news.cnet.com/8301-13556_3-10150841-61.html |title=Just don't call them private clouds |publisher=CNET News |date=2009-01-27 |accessdate=2010-08-22}}</ref><ref>{{Cite web|url=http://www.informationweek.com/cloud-computing/blog/archives/2009/01/theres_no_such.html |title=There's No Such Thing As A Private Cloud |publisher=InformationWeek |date=2010-06-30 |accessdate=2010-08-22}}</ref>


==The Intercloud==
The actual term "cloud" borrows from telephony in that telecommunications companies, that until the 1990s offered primarily 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 and that which was the responsibility of the user. Cloud computing extends this boundary to cover servers as well as the network infrastructure.<ref name="ATMMins">{{cite web |url=http://ftp.univie.ac.at/netinfo/ietf/atm/atm-minutes-93jul.txt |archiveurl=https://web.archive.org/web/20030722214022/http://ftp.univie.ac.at/netinfo/ietf/atm/atm-minutes-93jul.txt |title=Minutes of the IP Over Asynchronous Transfer Mode Working Group (ATM) |author=Laubach, Mark |publisher=Hewlett-Packard |date=July 1993 |archivedate=22 July 2003 |accessdate=14 April 2020}}</ref>
The [[Intercloud]]<ref>{{Cite journal|date=2009-05-24|title= Blueprint for the Intercloud – Protocols and Formats for Cloud Computing Interoperability|publisher=IEEE Computer Society|pages=328–336|url=http://www2.computer.org/portal/web/csdl/doi/10.1109/ICIW.2009.55|doi=10.1109/ICIW.2009.55|last1=Bernstein|first1=David|last2=Ludvigson|first2=Erik|last3=Sankar|first3=Krishna|last4=Diamond|first4=Steve|last5=Morrow|first5=Monique}}</ref> is an interconnected global "cloud of clouds"<ref name="kk">{{Cite web|url=http://www.kk.org/thetechnium/archives/2007/11/a_cloudbook_for.php |title=Kevin Kelly: A Cloudbook for the Cloud |publisher=Kk.org |date= |accessdate=2010-08-22}}</ref><ref>{{Cite web|url=http://samj.net/2009/06/intercloud-is-global-cloud-of-clouds.html |title=Intercloud is a global cloud of clouds |publisher=Samj.net |date=2009-06-22 |accessdate=2010-08-22}}</ref> and an extension of the Internet "network of networks" on which it is based.<ref>{{Cite web|url=http://www.readwriteweb.com/archives/vint_cerf_despite_its_age_the.php?mtcCampaign=2765 |title=Vint Cerf: Despite Its Age, The Internet is Still Filled with Problems |publisher=Readwriteweb.com |date= |accessdate=2010-08-22}}</ref><ref>{{Cite web|url=http://blogs.cisco.com/sp/comments/from_india_to_intercloud/ |title=SP360: Service Provider: From India to Intercloud |publisher=Blogs.cisco.com |date= |accessdate=2010-08-22}}</ref><ref>{{Cite news|author=Canada |url=http://www.theglobeandmail.com/servlet/story/LAC.20071129.TWLINKS29/TPStory/Business |title=Head in the clouds? Welcome to the future |publisher=Theglobeandmail.com |date= 2007-11-29|accessdate=2010-08-22 |location=Toronto}}</ref>


==Issues==
By the beginning of the twenty-first century, the advent of [[Desktop virtualization|virtualization]] technology and cost effective computing hardware, as well as ubiquitous Internet connectivity, enabled a first wave of cloud services, including Salesforce.com in 1999 and Amazon Web Services in 2002.<ref name="CWHistOfCC">{{cite web |url=https://www.computerweekly.com/feature/A-history-of-cloud-computing |archiveurl=https://web.archive.org/web/20210828084309/https://www.computerweekly.com/feature/A-history-of-cloud-computing |title=A history of cloud computing |author=Mohamed, A. |work=ComputerWeekly.com |publisher=TechTarget |date=09 April 2018 |archivedate=28 August 2021 |accessdate=07 January 2022}}</ref> After the dot-com bubble, Amazon continued to play key role in the development of cloud computing by modernizing their [[data center]]s, which, like most computer networks, were using as little as 10 percent of their capacity at any one time, just to leave room for occasional spikes. Having found the new cloud architecture resulted in significant internal efficiency improvements whereby small, fast-moving "two-pizza teams" could add new features faster and more easily, Amazon initiated a new commercial cloud-based project, launching its Elastic Compute cloud (EC2) in 2006.<ref name="CWHistOfCC" />
=== 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.<ref>{{Cite news|last=Cauley |first=Leslie |url=http://www.usatoday.com/news/washington/2006-05-10-nsa_x.htm |title=NSA has massive database of Americans' phone calls |publisher=USATODAY.com |date=2006-05-11 |accessdate=2010-08-22}}</ref>
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."<ref>{{Cite web|url=http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1347&categoryID=112 |title=Feature Guide: Amazon EC2 Availability Zones |publisher=Amazon Web Services |date= |accessdate=2010-08-22}}</ref>


===Compliance===
In May 2008, Eucalyptus became the first open-source, Amazon Web Service API-compatible platform for deploying private clouds.<ref name="EucHist">{{cite web |url=https://www.eucalyptus.com/about/story |archiveurl=https://web.archive.org/web/20140626125211/https://www.eucalyptus.com/about/story |title=The Eucalyptus Story |publisher=Eucalyptus Systems, Inc |archivedate=26 June 2014 |accessdate=14 April 2020}}</ref> In early 2008, OpenNebula, enhanced in the RESERVOIR European Commission-funded project, became the first open-source software for deploying private and hybrid clouds and for the federation of clouds.<ref name="RochwergerIBM">{{cite journal |url=http://researchweb.watson.ibm.com/journal/abstracts/rd/534/rochwerger.html |archiveurl=https://web.archive.org/web/20120108183022/http://researchweb.watson.ibm.com/journal/abstracts/rd/534/rochwerger.html |journal=IBM Journal of Research and Development |title=The RESERVOIR Model and Architecture for Open Federated Cloud Computing |author=Rochwerger, B.; Caceres, J.; Montero, R.S. et al. |volume=53 |issue=4 |year=2009 |archivedate=08 January 2012 |accessdate=14 April 2020}}</ref> By mid-2008, technology research firm Gartner saw an opportunity for cloud computing "to shape the relationship among consumers of IT services, those who use IT services and those who sell them"<ref name="SchurrKeep">{{cite web |url=https://www.networkworld.com/article/2281563/keep-an-eye-on-cloud-computing.html |title=Keep an eye on cloud computing |author=Schurr, A. |publisher=Network World |date=08 July 2008 |accessdate=14 April 2020}}</ref> and observed that "organisations are switching from company-owned hardware and software assets to per-use service-based models" so that the "projected shift to cloud computing ... will result in dramatic growth in IT products in some areas and significant reductions in other areas."<ref name="GartnerITSpend">{{cite web |url=http://www.gartner.com/it/page.jsp?id=742913 |archiveurl=https://web.archive.org/web/20170703131346/http://www.gartner.com/newsroom/id/742913 |title=Gartner Says Worldwide IT Spending On Pace to Surpass Trillion in 2008 |publisher=Gartner, Inc |date=18 August 2008 |archivedate=03 July 2017 |accessdate=14 April 2020}}</ref>  
In order to obtain compliance with regulations including [[FISMA]], [[HIPAA]], and SOX in the United States, 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 that 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"<ref>{{Cite web|url=http://searchcompliance.techtarget.com/news/article/0,289142,sid195_gci1377298,00.html |title=FISMA compliance for federal cloud computing on the horizon in 2010 |publisher=SearchCompliance.com |date= |accessdate=2010-08-22}}</ref><ref>{{Cite web|url=http://googleenterprise.blogspot.com/2009/09/google-apps-and-government.html |title=Google Apps and Government |publisher=Official Google Enterprise Blog |date=2009-09-15 |accessdate=2010-08-22}}</ref> and Rackspace Cloud are able to claim PCI compliance.<ref>{{Cite web|url=http://www.rackspace.com/cloud/blog/2009/03/05/cloud-hosting-is-secure-for-take-off-mosso-enables-the-spreadsheet-store-an-online-merchant-to-become-pci-compliant/ |title=Cloud Hosting is Secure for Take-off: Mosso Enables The Spreadsheet Store, an Online Merchant, to become PCI Compliant |publisher=Rackspace |date=2009-03-14 |accessdate=2010-08-22}}</ref>


Many providers also obtain SAS 70 Type II certification, but this has been criticized on the grounds that the hand-picked set of goals and standards determined by the auditor and the auditee are often not disclosed and can vary widely.<ref>{{Cite web|url=http://searchcloudcomputing.techtarget.com/news/article/0,289142,sid201_gci1374629,00.html |title=Amazon gets SAS 70 Type II audit stamp, but analysts not satisfied |publisher=SearchCloudComputing.com |date=2009-11-17 |accessdate=2010-08-22}}</ref> Providers typically make this information available on request, under [[non-disclosure agreement]].<ref>{{Cite web|url=http://wistechnology.com/articles/6954/ |title=Assessing Cloud Computing Agreements and Controls |publisher=WTN News |date= |accessdate=2010-08-22}}</ref>
By 2013, Gartner was reporting the public cloud services market was forecast to grow 18.5 percent in 2013, totalling $131 billion worldwide, up from $111 billion in 2012. Infrastructure as a service (IaaS) made up the fastest-growing segment of the market, growing 42.4 percent in 2012 to $6.1 billion, with expectations of it growing 47.3 percent in 2013 to $9 billion.<ref name="GartnerCloudSpend">{{cite web |url=http://www.gartner.com/newsroom/id/2352816 |archiveurl=https://web.archive.org/web/20170218030806/http://www.gartner.com/newsroom/id/2352816 |title=Gartner Says Worldwide Public Cloud Services Market to Total $131 Billion |publisher=Gartner, Inc |date=28 February 2013 |archivedate=18 February 2017 |accessdate=14 April 2020}}</ref>


Customers in the EU contracting with cloud providers established outside the EU/EEA have to adhere to the EU regulations on export of personal data.<ref>{{Cite web|url=http://www.thomashelbing.com/en/how-new-eu-rules-data-export-affect-companies-and-outside-eu |title=How the New EU Rules on Data Export Affect Companies in and Outside the EU &#124; Dr. Thomas Helbing – Kanzlei für Datenschutz-, Online- und IT-Recht |publisher=Dr. Thomas Helbing |date= |accessdate=2010-08-22}}</ref>
By 2017, "edge computing" began to emerge as a viable option. Edge computing is a distributed computing paradigm that brings computation and storage closer to the location where is needed, thus improving response times and saving bandwidth. This in part has been driven by increasing use of mobile applications, and sensor-based [[internet of things]] devices.<ref name="SatyanarayananTheEmerg17">{{cite journal |title=The Emergence of Edge Computing |journal=Computer |author=Satyanarayanan, M. |volume=50 |issue=1 |pages=30–39 |year=2017 |doi=10.1109/MC.2017.9}}</ref> More broadly, by the late 2010s, a distinct trend in cloud computing was emerging, as noted by Varghese and Buyya: "The general trend seems to be towards making use of infrastructure from multiple providers and decentralising computing away from resources currently concentrated in data centers. This is in contrast to traditional cloud offerings from single providers. Consequently, new computing models to suit the demands of the market are emerging."<ref name="VargheseNextGen18">{{cite journal |title=Next generation cloud computing: New trends and research directions |journal=Future Generation Computer Systems |author=Varghese, B.; Buyya, R. |volume=79 |issue=Part 3 |pages=849–61 |year=2018 |doi=10.1016/j.future.2017.09.020}}</ref>


===Performance===
==Issues and concerns==
With the American average download speed at 4MiB/S cloud computing relies on a high speed infrastructure that does not exist. This makes cloud computing impractical in many environments, in fact many local networks would struggle to serve multiple cloud instances. Depending on the setup cloud computing can require very fast internet, less CPU intensive setups (for the client) simply stream video over the internet or a LAN.{{Citation needed|date=July 2011}}


===Criticism===
General criticisms of cloud computing state the term is too unspecific or even misleading. CEO Larry Ellison of Oracle Corporation asserts that cloud computing is "everything that we already do"<ref name="FarberOracle">{{cite web |url=https://www.cnet.com/news/oracles-ellison-nails-cloud-computing/ |title=Oracle's Ellison nails cloud computing |author=Farber, D. |work=CNET |publisher=CBS Interactive |date=26 September 2008 |accessdate=14 April 2020}}</ref> and that the company could simply "change the wording on some of our ads"
Some have come to criticize the term as being either too unspecific or even misleading. CEO Larry Ellison of Oracle Corporation asserts that cloud computing is "everything that we already do", claiming that the company could simply "change the wording on some of our ads" to deploy their cloud-based services.<ref name="ellisonhell">{{Cite web|author=“” |url=http://www.youtube.com/watch?v=0FacYAI6DY0 |title=Larry Ellison – What The Hell Is Cloud Computing? |publisher=YouTube |date= |accessdate=2010-08-22}}</ref><ref name="ellisonnail">{{Cite web|last=Farber |first=Dan |url=http://news.cnet.com/8301-13953_3-10052188-80.html |title=Oracle's Ellison nails cloud computing |publisher=CNET News |date=2008-09-26 |accessdate=2010-08-22}}</ref><ref>{{Cite web|url=http://www.computerworld.com.au/article/335674/oracle_launches_worldwide_cloud-computing_tour/ |title=Oracle launches worldwide cloud-computing tour |publisher=Computerworld |date=2010-02-10 |accessdate=2010-08-22}}</ref><ref>{{Cite web|author=By James Rogers |url=http://www.thestreet.com/story/10649557/1/oracles-ellison-issues-cloud-challenge.html |title=Oracle's Ellison Issues Cloud Challenge |publisher=Thestreet.com |date=2009-12-18 |accessdate=2010-08-22}}</ref><ref>{{Cite web|url=http://searchcloudcomputing.techtarget.com/news/article/0,289142,sid201_gci1384202,00.html |title=Oracle desperately seeking cloud cred |publisher=Searchcloudcomputing.techtarget.com |date=2010-02-16 |accessdate=2010-08-22}}</ref> [[Forrester Research]] VP Frank Gillett questions the very nature of and motivation behind the push for cloud computing, describing what he calls "cloud washing"—companies simply relabeling their products as "cloud computing", resulting in mere marketing innovation instead of "real" innovation.<ref>{{Cite web|author=“” |url=http://www.youtube.com/watch?v=f7wv1i8ubng |title=Cloud Computing is Hyped and Overblown |publisher=Youtube.com |date=2008-09-29 |accessdate=2010-08-22}}</ref><ref>{{Cite web|url=http://www.beet.tv/2008/09/cloud-computing.html |title=Cloud Computing is Hyped and Overblown, Forrester's Frank Gillett Big Tech Companies Have "Cloud Envy" |publisher=Beet.tv |date= |accessdate=2010-08-22}}</ref>
<ref name="KanaracusOracle">{{cite web |url=https://www.networkworld.com/article/2244231/oracle-launches-worldwide-cloud-computing-tour.html |title=Oracle launches worldwide cloud-computing tour |author=Kanaracus, C. |publisher=Network World |date=09 February 2010 |accessdate=14 April 2020}}</ref> to deploy cloud-based services.


GNU's Richard Stallman insists that the industry will only use the model to deliver services at ever increasing rates over proprietary systems, otherwise likening it to a "marketing hype campaign".<ref name="Stallman">[http://www.guardian.co.uk/technology/2008/sep/29/cloud.computing.richard.stallman ''Cloud computing is a trap, warns GNU founder Richard Stallman''], ''The Guardian'', par Bobbie Johnson, 29 septembre 2008</ref>
In 2008, Forrester Research VP Frank Gillett questioned the very nature of and motivation behind the push for cloud computing, describing what he calls "cloud washing"—companies simply relabeling their products as "cloud computing", resulting in mere marketing innovation instead of "real" innovation. <ref name="PlesserYT">{{cite web |url=https://www.youtube.com/watch?v=f7wv1i8ubng |title=Cloud Computing is Hyped and Overblown |author=Plesser, A. |publisher=YouTube |date=29 September 2008 |accessdate=14 April 2020}}</ref> That same year, GNU's Richard Stallman insisted the industry will only use the model to deliver services at ever increasing rates over proprietary systems, otherwise likening it to a "marketing hype campaign."<ref name="Stallman">{{cite web |url=https://www.theguardian.com/technology/2008/sep/29/cloud.computing.richard.stallman |title=Cloud computing is a trap, warns GNU founder Richard Stallman |author=Johnson, B. |work=The Guardian |date=29 September 2008 |accessdate=14 April 2020}}</ref>


===Legal===
===Privacy===
In March 2007, Dell applied to trademark the term "cloud computing" ({{US trademark|77139082}}) in the United States. The "Notice of Allowance" the company received in July 2008 was canceled in August, resulting in a formal rejection of the trademark application less than a week later.  Since 2007, the number of trademark filings covering cloud computing brands, goods, and services has increased rapidly.  As companies sought to better position themselves for cloud computing branding and marketing efforts, cloud computing trademark filings increased by 483% between 2008 and 2009. In 2009, 116 cloud computing trademarks were filed, and trademark analysts predict that over 500 such marks could be filed during 2010.<ref>{{Cite web|url=http://insidetrademarks.com/2010/03/24/cloud-computing-trademark-trends/ |title=Inside Trademarks March 24, 2010 |publisher=Insidetrademarks.com |date=2010-03-24 |accessdate=2010-08-22}}</ref>
The cloud model has been criticized by privacy advocates for the greater ease in which the companies hosting the cloud services control and monitor at will, lawfully or unlawfully, the communication and data stored between the user and the host company, leading to questions about whether or not privacy concerns can be addressed.<ref name="MaierCloud">{{cite web |url=https://mashable.com/2011/10/19/cloud-privacy/ |title=Can There Ever Really Be Privacy in the Cloud? |author=Maier, F. |publisher=Mashable |date=19 October 2011 |accessdate=14 April 2020}}</ref><ref name="SchwartzCloud">{{cite journal |url=https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2290303 |journal=University of Pennsylvania Law Review |title=Information Privacy in the Cloud |author=Schwartz, P.M. |volume=161 |issue=1623 |at=2290303 |year=2013 |accessdate=14 April 2020}}</ref>


Other legal cases may shape the use of cloud computing by the public sector. On October 29, 2010, Google filed a lawsuit against the U.S. Department of Interior, which opened up a bid for software that required that bidders use Microsoft's Business Productivity Online Suite. Google sued, calling the requirement "unduly restrictive of competition."<ref>[http://www.scribd.com/doc/40513712/Google-v-US-Complaint Google, Inc. vs. the United States]</ref> Scholars have pointed out that, beginning in 2005, the prevalence of open standards and open source may have an impact on the way that public entities choose to select vendors.<ref>[http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1656616 Casson and Ryan, Open Standards, Open Source Adoption in the Public Sector, and Their Relationship to Microsoft’s Market Dominance]</ref>
===Compliance===
In order to obtain compliance with regulations including FISMA, [[HIPAA]], and SOX in the United States, the Data Protection Directive in the European Union, and the credit card industry's PCI DSS, users may have to adopt community or hybrid deployment modes that 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"<ref name="HowardFed">{{cite web |url=https://searchcompliance.techtarget.com/news/1377298/FISMA-compliance-for-federal-cloud-computing-on-the-horizon-in-2010 |archiveurl=https://web.archive.org/web/20200812174422/https://searchcompliance.techtarget.com/news/1377298/FISMA-compliance-for-federal-cloud-computing-on-the-horizon-in-2010 |title=FISMA compliance for federal cloud computing on the horizon in 2010 |author=Howard, A.B. |work=SearchCompliance |publisher=TechTarget |date=18 December 2009 |archivedate=12 August 2020 |accessdate=07 January 2022}}</ref><ref name="GlotzbachGov">{{cite web |url=https://cloud.googleblog.com/2009/09/google-apps-and-government.html |title=Google Apps and Government |author=Glotzbach, M. |work=Google Official Enterprise Blog |publisher=Google |date=15 September 2009 |accessdate=14 April 2020}}</ref> and Rackspace Cloud are able to claim PCI compliance.<ref name="BartelsSecure">{{cite web|url=http://www.rackspace.com/cloud/blog/2009/03/05/cloud-hosting-is-secure-for-take-off-mosso-enables-the-spreadsheet-store-an-online-merchant-to-become-pci-compliant/ |archiveurl=https://web.archive.org/web/20110223172816/http://www.rackspace.com/cloud/blog/2009/03/05/cloud-hosting-is-secure-for-take-off-mosso-enables-the-spreadsheet-store-an-online-merchant-to-become-pci-compliant/ |title=Cloud Hosting is Secure for Take-off: Mosso Enables The Spreadsheet Store, an Online Merchant, to become PCI Compliant |author=Bartels, Angela |publisher=Rackspace |date=05 March 2009 |archivedate=23 February 2011 |accessdate=21 August 2014}}</ref>


There are also concerns about a cloud provider shutting down for financial or legal reasons, which has happened in a number of cases.<ref>{{Cite web|last=Scheier |first=Robert L. |url=http://www.infoworld.com/d/cloud-computing/what-do-if-your-cloud-provider-disappears-508 |title=What to do if your cloud provider disappears &#124; Cloud Computing |publisher=InfoWorld |date=2009-04-20 |accessdate=2010-08-22}}</ref>
Many providers also obtain SAS 70 Type II certification, but this has been criticized on the grounds that the hand-picked set of goals and standards determined by the auditor and the auditee are often not disclosed and can vary widely.<ref name="BrooksAmazon">{{cite web |url=https://searchcloudcomputing.techtarget.com/news/1374629/Amazon-gets-SAS-70-Type-II-audit-stamp-but-analysts-not-satisfied |archiveurl=https://web.archive.org/web/20181022113325/https://searchcloudcomputing.techtarget.com/news/1374629/Amazon-gets-SAS-70-Type-II-audit-stamp-but-analysts-not-satisfied |title=Amazon gets SAS 70 Type II audit stamp, but analysts not satisfied |author=Brooks, C. |work=SearchCloudComputing |publisher=TechTarget |date=17 November 2009 |archivedate=22 October 2018 |accessdate=07 January 2022}}</ref> Providers typically make this information available on request, under non-disclosure agreement.<ref>{{cite web |url=http://wtnnews.com/articles/6954/ |archiveurl=https://web.archive.org/web/20150403061012/http://wtnnews.com/articles/6954/ |title=Assessing Cloud Computing Agreements and Controls |author=Norton, Jerry |work=WTN News |publisher=WTN Media |date=31 December 2009 |archivedate=03 April 2015 |accessdate=07 January 2022}}</ref>


===Open source===
Customers in the European Union contracting with cloud providers established outside the area have to adhere to the European Union's regulations on export of personal data.<ref>{{Cite web |url=https://www.thomashelbing.com/en/blog/how-new-eu-rules-data-export-affect-companies-and-outside-eu |title=How the New EU Rules on Data Export Affect Companies in and Outside the EU |author=Helbing, T. |publisher=Dr. Thomas Helbing |date=29 August 2012 |accessdate=14 April 2020}}</ref>
[[Open source software]] has provided the foundation for many cloud computing implementations, one prominent example being the Hadoop framework.<ref>{{Cite web|url=http://www.networkworld.com/news/2008/072808-open-source-cloud-computing.html |title=Open source fuels growth of cloud computing, software-as-a-service |publisher=Network World |date= |accessdate=2010-08-22}}</ref> 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.<ref>{{Cite web|url=http://redmonk.com/sogrady/2009/04/15/open-source-licensing-in-a-networked-age/ |title=AGPL: Open Source Licensing in a  Networked Age |publisher=Redmonk.com |date=2009-04-15 |accessdate=2010-08-22}}</ref>


===Open standards===
===Performance===
Most  cloud providers expose [[Application programming interface|APIs]] that are typically well-documented (often under a Creative Commons license<ref>[http://www.gogrid.com/company/press-releases/gogrid-moves-api-specification-to-creativecommons.php GoGrid Moves API Specification to Creative Commons]{{Dead link|date=August 2010}}</ref>) but 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, with a view to delivering interoperability and portability.<ref>{{Cite web|url=http://ostatic.com/blog/eucalyptus-completes-amazon-web-services-specs-with-latest-release |title=Eucalyptus Completes Amazon Web Services Specs with Latest Release |publisher=Ostatic.com |date= |accessdate=2010-08-22}}</ref>
Public cloud instances typically function well at the server and client hardware; however, speed across the connecting public Internet pipeline can vary significantly. Internet speeds can be asymmetrical and non-guaranteed, bandwidth may need to be shared, and Internet traffic rarely follow the same path, constraining performance and making a cloud option less appealing than a localized option.<ref name="RichardsSpeed">{{cite web |url=http://www.trinustech.com/cloud-computing-storm-or-silver-lining-pt-2/ |archiveurl=https://web.archive.org/web/20150121005425/http://www.trinustech.com/cloud-computing-storm-or-silver-lining-pt-2/ |title=Cloud Computing – Storm or Silver Lining? Pt 2 |author=Richards, B. |publisher=Trinus Technologies Inc |date=17 June 2013 |archivedate=21 January 2015 |accessdate=14 April 2020}}</ref> Poor upload speeds, especially from non-business home accounts, are also quoted as a factor limiting cloud computing's appeal.<ref name="JenksCloud">{{cite web |url=http://www.stephenjenks.com/2011/11/cloud-computing-for-home-has-huge-problems/ |title=Cloud Computing for Home Has Huge Problems |author=Jenks, Stephen |work=Stephen Jenks' Blog |date=08 November 2011 |accessdate=21 August 2014}}</ref>


===Security===
===Legal===
As cloud computing is achieving increased popularity, concerns are being voiced about the security issues introduced through the adoption of this new model. The effectiveness and efficiency of traditional protection mechanisms are being reconsidered as the characteristics of this innovative deployment model differ widely from those of traditional architectures.<ref name="Zissis 10">{{cite journal|last=Zissis|first=Dimitrios|coauthors=Lekkas|title=Addressing cloud computing security issues|journal=Future Generation Computer Systems|year=2010|doi=10.1016/j.future.2010.12.006|url=http://www.sciencedirect.com/science/article/pii/S0167739X10002554}}</ref>
Since 2007, the number of trademark filings covering cloud computing brands, goods, and services has increased rapidly. For example, in March 2007, Dell applied to trademark the term "cloud computing" ({{US trademark|77139082}}) in the United States. The "Notice of Allowance" the company received in July 2008 was canceled in August, resulting in a formal rejection of the trademark application less than a week later. As Dell and other companies sought to better position themselves for cloud computing branding and marketing efforts, cloud computing trademark filings increased by 483 percent between 2008 and 2009. In 2009, 116 cloud computing trademarks were filed, and trademark analysts predicted that over 500 such marks could be filed during 2010.<ref name="Trademarks">{{cite web |url=http://insidetrademarks.com/2010/03/24/cloud-computing-trademark-trends/ |archiveurl=https://web.archive.org/web/20100328121742/http://insidetrademarks.com/2010/03/24/cloud-computing-trademark-trends/ |title=Cloud Computing Trademark Trends |publisher=Inside Trademarks |date=24 March 2010 |archivedate=28 March 2010 |accessdate=21 August 2014}}</ref>


The relative security of cloud computing services is a contentious issue that may be delaying its adoption.<ref>{{Cite web|url=http://www.networkworld.com/news/2009/042709-burning-security-cloud-computing.html |title=Are security issues delaying adoption of cloud computing? |publisher=Network World |date= |accessdate=2010-08-22}}</ref> Issues barring the adoption of cloud computing are due in large part to the private and public sectors unease surrounding the external management of security based services. It is the very nature of cloud computing based services, private or public, that promote external management of provided services. This delivers great incentive among cloud computing service providers in producing a priority in building and maintaining strong management of secure services.<ref>{{Cite web|url=http://www.networkworld.com/news/2010/022210-virtualization-cloud-security-debate.html |title=Security of virtualization, cloud computing divides IT and security pros |publisher=Network World |date=2010-02-22 |accessdate=2010-08-22}}</ref> Security issues have been categorized into sensitive data access, data segregation, privacy, bug exploitation, recovery, accountability, malicious insiders, management console security, account control, and multi-tenancy issues. Solution to various cloud security issues vary through cryptography, particularly public key infrastructure (PKI), use of multiple cloud providers, standardization of APIs, improving virtual machine support and legal support.<ref name="Zissis 10" /><ref>{{cite journal|last=Armbrust|first=M|coauthors=Fox, A., Griffith, R., Joseph, A., Katz, R., Konwinski, A., Lee, G., Patterson, D., Rabkin, A., Zaharia,|title=A view of cloud computing.|journal=Communication of the ACM|year=2010|volume=53|issue=4|pages=50–58|doi=10.1145/1721654.1721672}}</ref><ref>{{cite journal|last=Anthens|first=G|title=Security in the cloud|journal=Communications of the ACM|volume=53|issue=11|doi=10.1145/1839676.1839683}}</ref>
Other legal cases may shape the use of cloud computing by the public sector. On October 29, 2010, Google filed a lawsuit against the U.S. Department of Interior, which opened up a bid for software that required bidders use Microsoft's Business Productivity Online Suite. Google sued, calling the requirement "unduly restrictive of competition."<ref name="GoogleUS">{{cite web |url=https://www.scribd.com/document/40513712/Google-v-US-Complaint |title=Google v US Complaint |publisher=Scribd |date=31 October 2010 |accessdate=14 April 2020}}</ref> Scholars have pointed out that, beginning in 2005, the prevalence of open standards and open-source software options may have an impact on the way public entities choose to select vendors and their software.<ref>{{cite web |url=https://papers.ssrn.com/sol3/papers.cfm?abstract_id=1656616 |title=Open Standards, Open Source Adoption in the Public Sector, and Their Relationship to Microsoft’s Market Dominance |author=Casson, T.; Ryan, P.S. |publisher=Social Science Electronic Publishing |date=01 May 2006 |accessdate=14 April 2020}}</ref>


===Sustainability===
Concerns about the legal and financial repercussions of a cloud provider shutting down, which has happened in a number of cases, also exist.<ref name="ScheiferCloud">{{cite web |url=https://www.infoworld.com/article/2634406/cloud-computing-what-to-do-if-your-cloud-provider-disappears.html |title=What to do if your cloud provider disappears |author=Scheier, R.L |work=InfoWorld |publisher=IDG Network |date=20 April 2009 |accessdate=14 April 2020}}</ref>
Although cloud computing is often assumed to be a form of "[[green computing]]", there is as of yet no published study to substantiate this assumption.<ref>{{Cite news
| author = James Urquhart
| title = Cloud computing's green paradox
| quote = ...there is some significant evidence that the cloud is encouraging more compute consumption
| publisher = CNET News
| date = January 7, 2010
| pages =
| url = http://news.cnet.com/8301-19413_3-10428065-240.html
| accessdate = March 12, 2010
}}</ref> Siting the servers affects the environmental effects of cloud computing. In areas where climate favors natural cooling and renewable electricity is readily available, the environmental effects will be more moderate. Thus countries with favorable conditions, such as Finland,<ref>[http://www.fincloud.freehostingcloud.com/ Finland – First Choice for Siting Your Cloud Computing Data Center.]. Retrieved 4 August 2010.</ref> Sweden and Switzerland,<ref>[http://www.greenbiz.com/news/2010/06/30/swiss-carbon-neutral-servers-hit-cloud Swiss Carbon-Neutral Servers Hit the Cloud.]. Retrieved 4 August 2010.</ref> are trying to attract cloud computing data centers.


===Abuse===
===Open standards===
As with privately purchased hardware, crackers posing as legitimate customers can purchase the services of cloud computing for nefarious purposes. This includes password cracking and as a means of launching attacks.<ref>http://www.bloomberg.com/news/2011-05-13/sony-network-said-to-have-been-invaded-by-hackers-using-amazon-com-server.html</ref> In 2009, a banking trojan illegally used the popular Amazon service as a command and control channel that issued software updates and malicious instructions to PCs that were infected by the malware.<ref>http://www.theregister.co.uk/2011/05/14/playstation_network_attack_from_amazon/</ref>
Most cloud providers expose APIs that are typically well-documented (often under a Creative Commons license<ref name="GoGrid">{{cite web |url=http://www.gogrid.com/company/press-releases/gogrid-moves-api-specification-to-creativecommons.php |archiveurl=https://web.archive.org/web/20090201061221/http://gogrid.com/company/press-releases/gogrid-moves-api-specification-to-creativecommons.php |title=GoGrid Moves API Specification to Creative Commons |publisher=ServePath |date=20 January 2009 |archivedate=01 February 2009 |accessdate=21 August 2014}}</ref>) but 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, with a view to delivering interoperability and portability.<ref name="EucAma">{{cite web |url=http://ostatic.com/blog/eucalyptus-completes-amazon-web-services-specs-with-latest-release |archiveurl=https://web.archive.org/web/20120307062957/http://ostatic.com/blog/eucalyptus-completes-amazon-web-services-specs-with-latest-release |title=Eucalyptus Completes Amazon Web Services Specs with Latest Release |author=Brockmeier, J. |publisher=OStatic |date=19 February 2010 |archivedate=07 March 2012 |accessdate=14 April 2020}}</ref>


===Cloud Computing Contracts===
===Security===
Most transitions to a cloud computing solution entail a change from a technically managed solution to a contractually managed solution. This change necessitates increased IT contract negotiation skills to establish the terms of the relationship and vendor management skills to maintain the relationship. All rights and responsibilities that are associated with the relationship between a client and a cloud computing services provider must be codified in the contract and effectively managed until the relationship has been terminated. Key risks and issues that are either unique to cloud computing or essential to its effective adoption typically involve service level agreements; data processing and access; provider infrastructure and security; and contract and vendor management.<ref>http://www.educause.edu/EDUCAUSE+Quarterly/EDUCAUSEQuarterlyMagazineVolum/IfItsintheCloudGetItonPaperClo/206532</ref>
As cloud computing increases in popularity, concerns are being raised about the security issues introduced through the adoption of this new model. The effectiveness and efficiency of traditional protection mechanisms are being reconsidered as the characteristics of this innovative deployment model differ widely from those of traditional architectures.<ref name="Zissis10">{{cite journal |title=Addressing cloud computing security issues |journal=Future Generation Computer Systems |author=Zissis, D.; Lekkas, D. |volume=28 |issue=3 |pages=583–92 |year=2012 |doi=10.1016/j.future.2010.12.006}}</ref>


==Research==
Issues barring the adoption of cloud computing are due in large part to the private and public sectors' unease surrounding the external management of security based services. It is the very nature of cloud computing based services, private or public, that promote external management of provided services. This delivers great incentive among cloud computing service providers in producing a priority in building and maintaining strong management of secure services.<ref name="MessmerSecurity10">{{cite web |url=https://www.networkworld.com/article/2244954/security-of-virtualization--cloud-computing-divides-it-and-security-pros.html |title=Security of virtualization, cloud computing divides IT and security pros |author=Messmer, E. |publisher=Network World |date=22 February 2010 |accessdate=14 April 2020}}</ref> Security issues have been categorized into sensitive data access, data segregation, privacy, bug exploitation, recovery, accountability, malicious insiders, management console security, account control, and multi-tenancy issues. Solutions to various cloud security issues vary from cryptography (particularly public key infrastructure), use of multiple cloud providers, standardization of APIs, improving virtual machine support, and legal support.<ref name="Zissis10" /><ref name="Armbrust10">{{cite journal |title=A view of cloud computing |journal=Communications of the ACM |author=Armbrust, M.; Fox, A.; Griffith, R. et al. |volume=53 |issue=4 |pages=50–58 |year=2010 |doi=10.1145/1721654.1721672}}</ref><ref name="AnthesSecurity10">{{cite journal |title=Security in the cloud |journal=Communications of the ACM |author=Anthes, G. |volume=53 |issue=11 |pages=16–18 |year=2010 |doi=10.1145/1839676.1839683}}</ref>
Many universities, vendors and government organizations are investing in research around the topic of cloud computing:<ref>{{Cite web|url=http://www.cloudbook.net/directories/research-clouds |title=Cloud Net Directory. Retrieved 2010-03-01 |publisher=Cloudbook.net |date= |accessdate=2010-08-22}}</ref><ref>[http://www.nsf.gov/news/news_summ.jsp?cntn_id=114686 nsf.gov – National Science Foundation (NSF) News – National Science Foundation Awards Millions to Fourteen Universities for Cloud Computing Research – US National Science Foun...<!-- Bot generated title -->]</ref>


* In October 2007 the Academic Cloud Computing Initiative (ACCI) was announced as a multi-university project designed to enhance students' technical knowledge to address the challenges of cloud computing.<ref>{{Cite web|url=http://www.datacenterknowledge.com/archives/2008/05/02/ibm-google-team-on-an-enterprise-cloud/ |title="IBM, Google Team on an Enterprise Cloud." May 2008. Rich Miller Retrieved 2010-04-01 |publisher=DataCenterKnowledge.com |date=2008-05-02 |accessdate=2010-08-22}}</ref>
The complexity of security is further increased when data is distributed over a wider area or greater number of devices and in multi-tenant systems that are being shared by unrelated users. In addition, user access to security audit logs may be difficult or impossible. The move to private cloud installations are in part motivated by users' desire to retain control over the infrastructure and avoid losing control of information security.


* On March 23, 2011, a nonprofit organization called Open Networking Foundation was founded, focused on providing support for a new cloud initiative called Software-Defined Networking.<ref>[http://www.openflow.org/wp/2011/03/open-networking-foundation-formed-to-speed-network-innovation/  Open Networking Foundation News Release. March 21, 2011.]</ref>
===Contracts===
Most transitions to a cloud computing solution entail a change from a technically managed solution to a contractually managed solution. This change necessitates increased IT contract negotiation skills to establish the terms of the relationship and vendor management skills to maintain the relationship. All rights and responsibilities associated with the relationship between a client and a provider must be codified in the contract and effectively managed until the relationship has been terminated. Key risks and issues that are either unique to cloud computing or essential to its effective adoption typically involve service level agreements; data processing and access; provider infrastructure and security; and contract and vendor management.<ref name="TrappierCloud">{{cite web |url=https://er.educause.edu/articles/2010/6/if-its-in-the-cloud-get-it-on-paper-cloud-computing-contract-issues |title=If It's in the Cloud, Get It on Paper: Cloud Computing Contract Issues |author=Trappier, T. |publisher=EDUCAUSE |date=24 June 2010 |accessdate=14 April 2020}}</ref>


==Further reading==
* {{cite book |url=https://books.google.com/books?id=GjsH0HJ2PmYC&pg=PT10&lpg=PT10 |title=Auditing Cloud Computing: A Security and Privacy Guide |author=Halpert, Ben |publisher=John Wiley & Sons |pages=206 |year=2011 |isbn=9780470874745}}
* {{cite book |url=https://www.amazon.com/Architecting-Cloud-Decisions-Computing-Service/dp/1118617614 |title=Architecting the Cloud: Design Decisions for Cloud Computing Service Models (SaaS, PaaS, and IaaS) |author=Kavis, Michael J |publisher=John Wiley & Sons |year=2014 |pages=224 |isbn=9781118617618}}
==Notes==
==Notes==


This article heavily reuses content from [http://en.wikipedia.org/wiki/Cloud_computing the Wikipedia article].
This article reuses numerous content elements from [https://en.wikipedia.org/wiki/Cloud_computing the Wikipedia article].


==References==
==References==
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[[Category:Software terms]]
[[Category:Cloud computing]]

Latest revision as of 21:08, 19 September 2022

Cloud computing logical diagram

Cloud computing is the delivery of computing as a service rather than a product, whereby shared resources, software, and information are provided to computers and other devices as a utility (like the electricity grid) over a network, typically the Internet.

Cloud computing describes a new supplement, consumption, and delivery model for IT services based on Internet protocols, and it typically involves provisioning of dynamically scalable and often virtualized resources[1][2] Details are abstracted from end-users, who no longer have need for expertise in, or control over, the technology infrastructure "in the cloud" that supports them.[3]

Cloud computing typically takes the form of web-based tools or applications that users can access and use through a web browser as if they were programs installed locally on their own computers. Those applications and resulting data are stored on servers at a remote location. In some cases, legacy applications (line of business applications that until now have been prevalent in thin client Windows computing) are delivered via a screen-sharing technology, while the computing resources are consolidated at a remote data center location; in other cases, entire business applications have been coded using web-based technologies such as Ajax.

Overview

Term

The term "cloud" is used as a metaphor for the Internet, based on the cloud drawing used in the past to represent the telephone network,[4] and later to depict the Internet in computer network diagrams as an abstraction of the underlying infrastructure it represents.[5]

Characteristics

The National Institute of Standards and Technology (NIST) offers an authoritative definition of cloud computing. That definition encompasses the essential characteristics, service models, and deployment models of the service. Of the essential characteristics, cloud computing must[6]:

  • provide computing capabilities and services on an as-needed basis, without human intervention;
  • be broadly accessible from a wide variety of standard desktop and mobile platforms;
  • make storage, processing, memory, and network bandwidth available as pooled, multi-tenant resources;
  • make those resources scalable with demand, often automatically, at any time; and
  • meter those resources and make the resulting information transparently available to both provider and consumer.

Additional, more granular characteristics of cloud computing include the following.

  • An application programming interface (API) enables machines to interact with cloud software in the same way the user interface facilitates interaction between humans and computers. Cloud computing systems typically use REST-based APIs.
  • Cost is potentially reduced in a public cloud delivery model, with capital expenditure being converted to operational expenditure, including research, development, and sales.[7] This is purported to lower 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 in-house IT skills are required for implementation.[8]
  • 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 phone).[9] As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet, users can connect from anywhere.[8]
  • Multi-tenancy enables sharing of resources and costs across a large pool of users, allowing for centralization of infrastructure in locations with lower costs, peak-load capacity increases, and utilization and efficiency improvements.
  • Reliability is improved if multiple redundant sites are used, which makes well-designed cloud computing suitable for business continuity and disaster recovery.[10]
  • Services are scalable and elastic via dynamic, "on-demand" provisioning of resources on a fine-grained, self-service basis in real-time, without users having to engineer for peak loads.[11]
  • Performance is monitored, and consistent and loosely coupled architectures are constructed using web services as the system interface.[8]
  • Security could improve due to centralization of data, increased security-focused resources, etc., but concerns may persist about loss of control over certain sensitive data and the lack of security for stored kernels.
  • Maintenance of cloud computing applications is easier, because they do not need to be installed on each user's computer. They are easier to support and to improve, as the changes reach the clients instantly.

Service models

The NIST definition also details the service models, which include software as a service (SaaS; provider's application runs on their infrastructure), platform as a service (PaaS; consumer-created or -acquired application runs on provider's infrastructure), and infrastructure as a service (IaaS; customer deploys operating systems and applications over fundamental computing resources provisioned by the provider).[6]

SaaS

NIST's definition of cloud computing defines SaaS as[6]:

The capability provided to the consumer is to use the provider's applications running on a cloud infrastructure. The applications are accessible from various client devices through either a thin client interface, such as a web browser (e.g., web-based email), or a program interface. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings.

By not needing to manage the cloud infrastructure and platform where the application runs, the need to install and run the application on the cloud user's own computers is eliminated, simplifying maintenance and support. The pricing model for SaaS applications is typically a monthly or yearly flat fee per user, and as such prices become scalable and adjustable if users are added or removed at any point.

Proponents of this model claim that SaaS has the potential to reduce IT operational costs by outsourcing hardware and software maintenance and support to the cloud provider. This enables the business to reallocate IT operations costs away from hardware/software spending and from personnel expenses, towards meeting other goals. In addition, with applications hosted centrally, updates can be released without the need for users to install new software.[12]

PaaS

NIST's definition of cloud computing defines PaaS as[6]:

The capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages, libraries, services, and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly configuration settings for the application-hosting environment.

As such, PaaS users do not manage or control the underlying cloud infrastructure, including network, servers, operating systems, or storage. Rather, they have control over the deployed applications, and in some cases the configuration settings for the application-hosting environment.[12]

IaaS

NIST's definition of cloud computing describes IaaS as a platform "where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, and deployed applications, and possibly limited control of select networking components (e.g., host firewalls)."[6]

IaaS-cloud providers supply these resources on-demand from their large pools of equipment installed in data centers. For wide area network connectivity, customers can use either the internet or carrier clouds (dedicated virtual private networks). To deploy their applications, cloud users install operating-system images and their application software on the cloud infrastructure. The cloud user patches and maintains the operating systems and the application software on the infrastructure. Cloud providers typically bill IaaS services on a utility computing basis: cost reflects the amount of resources allocated and consumed.[12]

Deployment models

Cloud computing deployment types

The NIST definition identifies four deployment models for cloud computing.[6]

Private cloud: an infrastructure operated solely for a single organization, whether managed internally or by a third-party and hosted internally or externally

Community cloud: an infrastructure shared between several organisations from a specific community with common concerns (security, compliance, jurisdiction, etc.), managed internally or by a third-party and hosted internally or externally

Public cloud: an infrastructure where resources are dynamically provisioned to the general public on a fine-grained, self-service basis over the Internet, via web applications/web services, from an off-site third-party provider who bills on a metered basis

Hybrid cloud: a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together, offering the benefits of multiple deployment models

Other deployment options have arisen as well. Another (potentially classifiable as "hybrid") that has become more notable is carrier cloud, cloud computing services integrated into a communications service provider's network infrastructure.[13][14] Others include distributed cloud (a distributed set of machines in different locations)[15], high-performance computing cloud (able to handle high-performance computing applications)[16], and polycloud (use of multiple public clouds from different providers, levaraging specific services each offers).[17]

History

The underlying concept of cloud computing dates back to the 1960s, when John McCarthy opined that "computation may someday be organized as a public utility."[18] Almost all the modern-day characteristics of cloud computing (elastic provision, provided as a utility, online, illusion of infinite supply), as well as the comparison to the electricity industry and the use of public, private, government, and community forms, were thoroughly explored in Douglas Parkhill's 1966 book, The Challenge of the Computer Utility.[19]

The actual term "cloud" borrows from telephony in that telecommunications companies, that until the 1990s offered primarily 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 and that which was the responsibility of the user. Cloud computing extends this boundary to cover servers as well as the network infrastructure.[20]

By the beginning of the twenty-first century, the advent of virtualization technology and cost effective computing hardware, as well as ubiquitous Internet connectivity, enabled a first wave of cloud services, including Salesforce.com in 1999 and Amazon Web Services in 2002.[21] After the dot-com bubble, Amazon continued to play key role in the development of cloud computing by modernizing their data centers, which, like most computer networks, were using as little as 10 percent of their capacity at any one time, just to leave room for occasional spikes. Having found the new cloud architecture resulted in significant internal efficiency improvements whereby small, fast-moving "two-pizza teams" could add new features faster and more easily, Amazon initiated a new commercial cloud-based project, launching its Elastic Compute cloud (EC2) in 2006.[21]

In May 2008, Eucalyptus became the first open-source, Amazon Web Service API-compatible platform for deploying private clouds.[22] In early 2008, OpenNebula, enhanced in the RESERVOIR European Commission-funded project, became the first open-source software for deploying private and hybrid clouds and for the federation of clouds.[23] By mid-2008, technology research firm Gartner saw an opportunity for cloud computing "to shape the relationship among consumers of IT services, those who use IT services and those who sell them"[24] and observed that "organisations are switching from company-owned hardware and software assets to per-use service-based models" so that the "projected shift to cloud computing ... will result in dramatic growth in IT products in some areas and significant reductions in other areas."[25]

By 2013, Gartner was reporting the public cloud services market was forecast to grow 18.5 percent in 2013, totalling $131 billion worldwide, up from $111 billion in 2012. Infrastructure as a service (IaaS) made up the fastest-growing segment of the market, growing 42.4 percent in 2012 to $6.1 billion, with expectations of it growing 47.3 percent in 2013 to $9 billion.[26]

By 2017, "edge computing" began to emerge as a viable option. Edge computing is a distributed computing paradigm that brings computation and storage closer to the location where is needed, thus improving response times and saving bandwidth. This in part has been driven by increasing use of mobile applications, and sensor-based internet of things devices.[27] More broadly, by the late 2010s, a distinct trend in cloud computing was emerging, as noted by Varghese and Buyya: "The general trend seems to be towards making use of infrastructure from multiple providers and decentralising computing away from resources currently concentrated in data centers. This is in contrast to traditional cloud offerings from single providers. Consequently, new computing models to suit the demands of the market are emerging."[28]

Issues and concerns

General criticisms of cloud computing state the term is too unspecific or even misleading. CEO Larry Ellison of Oracle Corporation asserts that cloud computing is "everything that we already do"[29] and that the company could simply "change the wording on some of our ads" [30] to deploy cloud-based services.

In 2008, Forrester Research VP Frank Gillett questioned the very nature of and motivation behind the push for cloud computing, describing what he calls "cloud washing"—companies simply relabeling their products as "cloud computing", resulting in mere marketing innovation instead of "real" innovation. [31] That same year, GNU's Richard Stallman insisted the industry will only use the model to deliver services at ever increasing rates over proprietary systems, otherwise likening it to a "marketing hype campaign."[32]

Privacy

The cloud model has been criticized by privacy advocates for the greater ease in which the companies hosting the cloud services control and monitor at will, lawfully or unlawfully, the communication and data stored between the user and the host company, leading to questions about whether or not privacy concerns can be addressed.[33][34]

Compliance

In order to obtain compliance with regulations including FISMA, HIPAA, and SOX in the United States, the Data Protection Directive in the European Union, and the credit card industry's PCI DSS, users may have to adopt community or hybrid deployment modes that 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"[35][36] and Rackspace Cloud are able to claim PCI compliance.[37]

Many providers also obtain SAS 70 Type II certification, but this has been criticized on the grounds that the hand-picked set of goals and standards determined by the auditor and the auditee are often not disclosed and can vary widely.[38] Providers typically make this information available on request, under non-disclosure agreement.[39]

Customers in the European Union contracting with cloud providers established outside the area have to adhere to the European Union's regulations on export of personal data.[40]

Performance

Public cloud instances typically function well at the server and client hardware; however, speed across the connecting public Internet pipeline can vary significantly. Internet speeds can be asymmetrical and non-guaranteed, bandwidth may need to be shared, and Internet traffic rarely follow the same path, constraining performance and making a cloud option less appealing than a localized option.[41] Poor upload speeds, especially from non-business home accounts, are also quoted as a factor limiting cloud computing's appeal.[42]

Legal

Since 2007, the number of trademark filings covering cloud computing brands, goods, and services has increased rapidly. For example, in March 2007, Dell applied to trademark the term "cloud computing" (U.S. Trademark 77,139,082) in the United States. The "Notice of Allowance" the company received in July 2008 was canceled in August, resulting in a formal rejection of the trademark application less than a week later. As Dell and other companies sought to better position themselves for cloud computing branding and marketing efforts, cloud computing trademark filings increased by 483 percent between 2008 and 2009. In 2009, 116 cloud computing trademarks were filed, and trademark analysts predicted that over 500 such marks could be filed during 2010.[43]

Other legal cases may shape the use of cloud computing by the public sector. On October 29, 2010, Google filed a lawsuit against the U.S. Department of Interior, which opened up a bid for software that required bidders use Microsoft's Business Productivity Online Suite. Google sued, calling the requirement "unduly restrictive of competition."[44] Scholars have pointed out that, beginning in 2005, the prevalence of open standards and open-source software options may have an impact on the way public entities choose to select vendors and their software.[45]

Concerns about the legal and financial repercussions of a cloud provider shutting down, which has happened in a number of cases, also exist.[46]

Open standards

Most cloud providers expose APIs that are typically well-documented (often under a Creative Commons license[47]) but 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, with a view to delivering interoperability and portability.[48]

Security

As cloud computing increases in popularity, concerns are being raised about the security issues introduced through the adoption of this new model. The effectiveness and efficiency of traditional protection mechanisms are being reconsidered as the characteristics of this innovative deployment model differ widely from those of traditional architectures.[49]

Issues barring the adoption of cloud computing are due in large part to the private and public sectors' unease surrounding the external management of security based services. It is the very nature of cloud computing based services, private or public, that promote external management of provided services. This delivers great incentive among cloud computing service providers in producing a priority in building and maintaining strong management of secure services.[50] Security issues have been categorized into sensitive data access, data segregation, privacy, bug exploitation, recovery, accountability, malicious insiders, management console security, account control, and multi-tenancy issues. Solutions to various cloud security issues vary from cryptography (particularly public key infrastructure), use of multiple cloud providers, standardization of APIs, improving virtual machine support, and legal support.[49][51][52]

The complexity of security is further increased when data is distributed over a wider area or greater number of devices and in multi-tenant systems that are being shared by unrelated users. In addition, user access to security audit logs may be difficult or impossible. The move to private cloud installations are in part motivated by users' desire to retain control over the infrastructure and avoid losing control of information security.

Contracts

Most transitions to a cloud computing solution entail a change from a technically managed solution to a contractually managed solution. This change necessitates increased IT contract negotiation skills to establish the terms of the relationship and vendor management skills to maintain the relationship. All rights and responsibilities associated with the relationship between a client and a provider must be codified in the contract and effectively managed until the relationship has been terminated. Key risks and issues that are either unique to cloud computing or essential to its effective adoption typically involve service level agreements; data processing and access; provider infrastructure and security; and contract and vendor management.[53]

Further reading

Notes

This article reuses numerous content elements from the Wikipedia article.

References

  1. ↑ "Gartner Says Cloud Computing Will Be As Influential As E-business". Gartner, Inc. 26 June 2008. Archived from the original on 28 August 2018. https://web.archive.org/web/20180828134416/https://www.gartner.com/newsroom/id/707508. Retrieved 14 April 2020. 
  2. ↑ Knorr, E. (2 October 2018). "What is cloud computing? Everything you need to know now". InfoWorld. IDG Network. https://www.infoworld.com/article/2683784/what-is-cloud-computing.html. Retrieved 14 April 2020. 
  3. ↑ Danielson, K. (26 March 2008). "Distinguishing Cloud Computing from Utility Computing". ebizQ. TechTarget. Archived from the original on 24 January 2020. https://web.archive.org/web/20200124141938/http://www.ebizq.net/blogs/saasweek/2008/03/distinguishing_cloud_computing/. Retrieved 07 January 2022. 
  4. ↑ Sells, Chris (1 July 1998). "Windows Telephony Programming: A Developer's Guide to TAPI". Sellsbrothers.com. Archived from the original on 02 May 2005. https://web.archive.org/web/20050502192319/http://www.sellsbrothers.com/writing/intro2tapi/default.aspx?content=pstn.htm. Retrieved 21 August 2014. 
  5. ↑ Scanlon,Jessie Holliday; Wieners, Brad (9 July 1999). "The Internet Cloud". The Industry Standard. IDG Network. Archived from the original on 11 February 2010. https://web.archive.org/web/20100211133442/http://www.thestandard.com/article/0,1902,5466,00.html. Retrieved 2010-08-22. 
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Mell, P.; Grance, T. (September 2011). "The NIST Definition of Cloud Computing". National Institute of Standards and Technology. https://csrc.nist.gov/publications/detail/sp/800-145/final. Retrieved 14 April 2020. 
  7. ↑ Columbus, L. (10 April 2013). "Making Cloud Computing Pay". Forbes. https://www.forbes.com/sites/louiscolumbus/2013/04/10/making-cloud-computing-pay-2/. Retrieved 14 April 2020. 
  8. ↑ 8.0 8.1 8.2 Gens, Frank (23 September 2008). "Defining "Cloud Services" and "Cloud Computing"". IDC. Archived from the original on 28 May 2017. https://web.archive.org/web/20170528125047/http://blogs.idc.com/ie/?p=190. Retrieved 14 April 2020. 
  9. ↑ Farber, D. (25 June 2008). "The new geek chic: Data centers". CNET. CBS Interactive. https://www.cnet.com/news/the-new-geek-chic-data-centers/. Retrieved 14 April 2020. 
  10. ↑ King, R. (4 August 2008). "Cloud Computing: Small Companies Take Flight". Bloomberg. https://www.bloomberg.com/news/articles/2008-08-04/cloud-computing-small-companies-take-flightbusinessweek-business-news-stock-market-and-financial-advice. Retrieved 14 April 2020. 
  11. ↑ Kuperberg, M.; Herbst, N.; von Kistowski, J.; Reussner, R. (2011). "Defining and Quantifying Elasticity of Resources in Cloud Computing and Scalable Platforms". Karlsruher Institut für Technologie. https://publikationen.bibliothek.kit.edu/1000023476. Retrieved 14 April 2020. 
  12. ↑ 12.0 12.1 12.2 Griffin, R. (2018). Internet Governance. ED-Tech Press. pp. 111–13. ISBN 9781839473951. https://books.google.com/books?id=OuTEDwAAQBAJ&pg=PA111. Retrieved 14 April 2020. 
  13. ↑ "Cloud Evolution: The Carrier Cloud" (PDF). Kontron. 2013. https://www.kontron.com/resources/collateral/white_papers/kontroncarriercloudwp.pdf. 
  14. ↑ Narcisi, G. (November 2013). "Carrier cloud services: Do customers care if you own the network?". SearchNetworking. TechTarget. Archived from the original on 24 June 2019. https://web.archive.org/web/20190624173258/https://searchnetworking.techtarget.com/feature/Carrier-cloud-services-Do-customers-care-if-you-own-the-network. Retrieved 07 January 2022. 
  15. ↑ Cunsolo, V.D.; Distefano, S.; Puliafito, A. et al. (2009). "Volunteer Computing and Desktop Cloud: The Cloud@Home Paradigm". 2009 Eighth IEEE International Symposium on Network Computing and Applications: 134–9. doi:10.1109/NCA.2009.41. 
  16. ↑ Netto, M.A.S.; Calheiros, R.N.; Rodrigues, E.R. et al. (2018). "HPC Cloud for Scientific and Business Applications: Taxonomy, Vision, and Research Challenges". AMC Computing Surveys 51 (1): 8. doi:10.1145/3150224. 
  17. ↑ Gall, R. (16 May 2018). "Polycloud: A better alternative to cloud agnosticism". Cloud and Networking News. Packt Publishing. https://hub.packtpub.com/polycloud-a-better-alternative-to-cloud-agnosticism/. Retrieved 14 April 2020. 
  18. ↑ Halpert, Ben (2011). "Chapter 1: Introduction to Cloud Computing". Auditing Cloud Computing: A Security and Privacy Guide. John Wiley & Sons. pp. 1–13. ISBN 9781118116043. https://books.google.com/books?id=GjsH0HJ2PmYC&pg=PT10&lpg=PT10. Retrieved 07 January 2022. 
  19. ↑ Parhill, Douglas (2006). The Challenge of the Computer Utility. Addison-Wesley Pub. Co. https://books.google.com/books?id=8kJZAAAAMAAJ. Retrieved 07 January 2022. 
  20. ↑ Laubach, Mark (July 1993). "Minutes of the IP Over Asynchronous Transfer Mode Working Group (ATM)". Hewlett-Packard. Archived from the original on 22 July 2003. https://web.archive.org/web/20030722214022/http://ftp.univie.ac.at/netinfo/ietf/atm/atm-minutes-93jul.txt. Retrieved 14 April 2020. 
  21. ↑ 21.0 21.1 Mohamed, A. (9 April 2018). "A history of cloud computing". ComputerWeekly.com. TechTarget. Archived from the original on 28 August 2021. https://web.archive.org/web/20210828084309/https://www.computerweekly.com/feature/A-history-of-cloud-computing. Retrieved 07 January 2022. 
  22. ↑ "The Eucalyptus Story". Eucalyptus Systems, Inc. Archived from the original on 26 June 2014. https://web.archive.org/web/20140626125211/https://www.eucalyptus.com/about/story. Retrieved 14 April 2020. 
  23. ↑ Rochwerger, B.; Caceres, J.; Montero, R.S. et al. (2009). "The RESERVOIR Model and Architecture for Open Federated Cloud Computing". IBM Journal of Research and Development 53 (4). Archived from the original on 08 January 2012. https://web.archive.org/web/20120108183022/http://researchweb.watson.ibm.com/journal/abstracts/rd/534/rochwerger.html. Retrieved 14 April 2020. 
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  25. ↑ "Gartner Says Worldwide IT Spending On Pace to Surpass Trillion in 2008". Gartner, Inc. 18 August 2008. Archived from the original on 03 July 2017. https://web.archive.org/web/20170703131346/http://www.gartner.com/newsroom/id/742913. Retrieved 14 April 2020. 
  26. ↑ "Gartner Says Worldwide Public Cloud Services Market to Total $131 Billion". Gartner, Inc. 28 February 2013. Archived from the original on 18 February 2017. https://web.archive.org/web/20170218030806/http://www.gartner.com/newsroom/id/2352816. Retrieved 14 April 2020. 
  27. ↑ Satyanarayanan, M. (2017). "The Emergence of Edge Computing". Computer 50 (1): 30–39. doi:10.1109/MC.2017.9. 
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  31. ↑ Plesser, A. (29 September 2008). "Cloud Computing is Hyped and Overblown". YouTube. https://www.youtube.com/watch?v=f7wv1i8ubng. Retrieved 14 April 2020. 
  32. ↑ Johnson, B. (29 September 2008). "Cloud computing is a trap, warns GNU founder Richard Stallman". The Guardian. https://www.theguardian.com/technology/2008/sep/29/cloud.computing.richard.stallman. Retrieved 14 April 2020. 
  33. ↑ Maier, F. (19 October 2011). "Can There Ever Really Be Privacy in the Cloud?". Mashable. https://mashable.com/2011/10/19/cloud-privacy/. Retrieved 14 April 2020. 
  34. ↑ Schwartz, P.M. (2013). "Information Privacy in the Cloud". University of Pennsylvania Law Review 161 (1623): 2290303. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2290303. Retrieved 14 April 2020. 
  35. ↑ Howard, A.B. (18 December 2009). "FISMA compliance for federal cloud computing on the horizon in 2010". SearchCompliance. TechTarget. Archived from the original on 12 August 2020. https://web.archive.org/web/20200812174422/https://searchcompliance.techtarget.com/news/1377298/FISMA-compliance-for-federal-cloud-computing-on-the-horizon-in-2010. Retrieved 07 January 2022. 
  36. ↑ Glotzbach, M. (15 September 2009). "Google Apps and Government". Google Official Enterprise Blog. Google. https://cloud.googleblog.com/2009/09/google-apps-and-government.html. Retrieved 14 April 2020. 
  37. ↑ Bartels, Angela (5 March 2009). "Cloud Hosting is Secure for Take-off: Mosso Enables The Spreadsheet Store, an Online Merchant, to become PCI Compliant". Rackspace. Archived from the original on 23 February 2011. https://web.archive.org/web/20110223172816/http://www.rackspace.com/cloud/blog/2009/03/05/cloud-hosting-is-secure-for-take-off-mosso-enables-the-spreadsheet-store-an-online-merchant-to-become-pci-compliant/. Retrieved 21 August 2014. 
  38. ↑ Brooks, C. (17 November 2009). "Amazon gets SAS 70 Type II audit stamp, but analysts not satisfied". SearchCloudComputing. TechTarget. Archived from the original on 22 October 2018. https://web.archive.org/web/20181022113325/https://searchcloudcomputing.techtarget.com/news/1374629/Amazon-gets-SAS-70-Type-II-audit-stamp-but-analysts-not-satisfied. Retrieved 07 January 2022. 
  39. ↑ Norton, Jerry (31 December 2009). "Assessing Cloud Computing Agreements and Controls". WTN News. WTN Media. Archived from the original on 03 April 2015. https://web.archive.org/web/20150403061012/http://wtnnews.com/articles/6954/. Retrieved 07 January 2022. 
  40. ↑ Helbing, T. (29 August 2012). "How the New EU Rules on Data Export Affect Companies in and Outside the EU". Dr. Thomas Helbing. https://www.thomashelbing.com/en/blog/how-new-eu-rules-data-export-affect-companies-and-outside-eu. Retrieved 14 April 2020. 
  41. ↑ Richards, B. (17 June 2013). "Cloud Computing – Storm or Silver Lining? Pt 2". Trinus Technologies Inc. Archived from the original on 21 January 2015. https://web.archive.org/web/20150121005425/http://www.trinustech.com/cloud-computing-storm-or-silver-lining-pt-2/. Retrieved 14 April 2020. 
  42. ↑ Jenks, Stephen (8 November 2011). "Cloud Computing for Home Has Huge Problems". Stephen Jenks' Blog. http://www.stephenjenks.com/2011/11/cloud-computing-for-home-has-huge-problems/. Retrieved 21 August 2014. 
  43. ↑ "Cloud Computing Trademark Trends". Inside Trademarks. 24 March 2010. Archived from the original on 28 March 2010. https://web.archive.org/web/20100328121742/http://insidetrademarks.com/2010/03/24/cloud-computing-trademark-trends/. Retrieved 21 August 2014. 
  44. ↑ "Google v US Complaint". Scribd. 31 October 2010. https://www.scribd.com/document/40513712/Google-v-US-Complaint. Retrieved 14 April 2020. 
  45. ↑ Casson, T.; Ryan, P.S. (1 May 2006). "Open Standards, Open Source Adoption in the Public Sector, and Their Relationship to Microsoft’s Market Dominance". Social Science Electronic Publishing. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=1656616. Retrieved 14 April 2020. 
  46. ↑ Scheier, R.L (20 April 2009). "What to do if your cloud provider disappears". InfoWorld. IDG Network. https://www.infoworld.com/article/2634406/cloud-computing-what-to-do-if-your-cloud-provider-disappears.html. Retrieved 14 April 2020. 
  47. ↑ "GoGrid Moves API Specification to Creative Commons". ServePath. 20 January 2009. Archived from the original on 01 February 2009. https://web.archive.org/web/20090201061221/http://gogrid.com/company/press-releases/gogrid-moves-api-specification-to-creativecommons.php. Retrieved 21 August 2014. 
  48. ↑ Brockmeier, J. (19 February 2010). "Eucalyptus Completes Amazon Web Services Specs with Latest Release". OStatic. Archived from the original on 07 March 2012. https://web.archive.org/web/20120307062957/http://ostatic.com/blog/eucalyptus-completes-amazon-web-services-specs-with-latest-release. Retrieved 14 April 2020. 
  49. ↑ 49.0 49.1 Zissis, D.; Lekkas, D. (2012). "Addressing cloud computing security issues". Future Generation Computer Systems 28 (3): 583–92. doi:10.1016/j.future.2010.12.006. 
  50. ↑ Messmer, E. (22 February 2010). "Security of virtualization, cloud computing divides IT and security pros". Network World. https://www.networkworld.com/article/2244954/security-of-virtualization--cloud-computing-divides-it-and-security-pros.html. Retrieved 14 April 2020. 
  51. ↑ Armbrust, M.; Fox, A.; Griffith, R. et al. (2010). "A view of cloud computing". Communications of the ACM 53 (4): 50–58. doi:10.1145/1721654.1721672. 
  52. ↑ Anthes, G. (2010). "Security in the cloud". Communications of the ACM 53 (11): 16–18. doi:10.1145/1839676.1839683. 
  53. ↑ Trappier, T. (24 June 2010). "If It's in the Cloud, Get It on Paper: Cloud Computing Contract Issues". EDUCAUSE. https://er.educause.edu/articles/2010/6/if-its-in-the-cloud-get-it-on-paper-cloud-computing-contract-issues. Retrieved 14 April 2020. 
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