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8/7/2019 Cloud Computing is Internet
1/24
Cloud computing is Internet-based computing, whereby shared resources, software and
information are provided to computers and other devices on-demand, like a public utility.
It is aparadigm shiftfollowing the shift from mainframeto client-serverthat preceded itin the early '80s. Details are abstracted from the users who no longer have need of,
expertise in, or control over the technology infrastructure "in the cloud" that supportsthem.[1] Cloud computing describes a new supplement, consumption and delivery model
for IT services based on the Internet, and it typically involves the provision ofdynamically scalable and often virtualizedresources as a service over the Internet.[2][3] It
is a byproduct and consequence of the ease-of-access to remote computing sites provided
by the Internet.[4]
The term cloudis used as ametaphorfor the Internet, based on the cloud drawing used inthe past to represent the telephone network,[5] and later to depict the Internet incomputer
network diagramsas anabstractionof the underlying infrastructure it represents.[6]
Typical cloud computing providers deliver commonbusiness applications online which
are accessed from another web service or software like aweb browser, while thesoftwareanddata are stored onservers.
A technical definition is "a computing capability that provides an abstraction between the
computing resource and its underlying technical architecture (e.g., servers, storage,networks), enabling convenient, on-demand network access to a shared pool of
configurable computing resources that can be rapidly provisioned and released with
minimal management effort or service provider interaction."[7] This definition states thatclouds have five essential characteristics: on-demand self-service, broad network access,
resource pooling, rapid elasticity, and measured service.[7]
Cloud computing is Internet-based computing, whereby shared resources, software andinformation are provided to computers and other devices on-demand, like a public utility.
It is aparadigm shiftfollowing the shift from mainframeto client-serverthat preceded it
in the early '80s. Details are abstracted from the users who no longer have need of,
expertise in, or control over the technology infrastructure "in the cloud" that supports
them.[1] Cloud computing describes a new supplement, consumption and delivery modelfor IT services based on the Internet, and it typically involves the provision of
dynamically scalable and often virtualizedresources as a service over the Internet.[2][3] It
is a byproduct and consequence of the ease-of-access to remote computing sites providedby the Internet.[4]
The term cloudis used as ametaphorfor the Internet, based on the cloud drawing used in
the past to represent the telephone network,[5] and later to depict the Internet incomputer
network diagramsas anabstractionof the underlying infrastructure it represents.[6]
Typical cloud computing providers deliver commonbusiness applications online which
are accessed from another web service or software like aweb browser, while thesoftware
anddata are stored onservers.
http://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Computinghttp://en.wikipedia.org/wiki/Paradigm_shifthttp://en.wikipedia.org/wiki/Paradigm_shifthttp://en.wikipedia.org/wiki/Mainframe_computerhttp://en.wikipedia.org/wiki/Mainframe_computerhttp://en.wikipedia.org/wiki/Client-serverhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-0%23cite_note-0http://en.wikipedia.org/wiki/Scalabilityhttp://en.wikipedia.org/wiki/Virtualizationhttp://en.wikipedia.org/wiki/Virtualizationhttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-gartner-1%23cite_note-gartner-1http://en.wikipedia.org/wiki/Cloud_computing#cite_note-really-2%23cite_note-really-2http://en.wikipedia.org/wiki/Computinghttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-3%23cite_note-3http://en.wikipedia.org/wiki/Metaphorhttp://en.wikipedia.org/wiki/Metaphorhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-4%23cite_note-4http://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Abstractionhttp://en.wikipedia.org/wiki/Abstractionhttp://en.wikipedia.org/wiki/Abstractionhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-5%23cite_note-5http://en.wikipedia.org/wiki/Business_applicationhttp://en.wikipedia.org/wiki/Web_browserhttp://en.wikipedia.org/wiki/Web_browserhttp://en.wikipedia.org/wiki/Web_browserhttp://en.wikipedia.org/wiki/Softwarehttp://en.wikipedia.org/wiki/Softwarehttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Server_(computing)http://en.wikipedia.org/wiki/Server_(computing)http://en.wikipedia.org/wiki/Cloud_computing#cite_note-csrc.nist.gov-6%23cite_note-csrc.nist.gov-6http://en.wikipedia.org/wiki/Cloud_computing#cite_note-csrc.nist.gov-6%23cite_note-csrc.nist.gov-6http://en.wikipedia.org/wiki/Cloud_computing#cite_note-csrc.nist.gov-6%23cite_note-csrc.nist.gov-6http://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Computinghttp://en.wikipedia.org/wiki/Paradigm_shifthttp://en.wikipedia.org/wiki/Paradigm_shifthttp://en.wikipedia.org/wiki/Mainframe_computerhttp://en.wikipedia.org/wiki/Mainframe_computerhttp://en.wikipedia.org/wiki/Client-serverhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-0%23cite_note-0http://en.wikipedia.org/wiki/Scalabilityhttp://en.wikipedia.org/wiki/Virtualizationhttp://en.wikipedia.org/wiki/Virtualizationhttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-gartner-1%23cite_note-gartner-1http://en.wikipedia.org/wiki/Cloud_computing#cite_note-really-2%23cite_note-really-2http://en.wikipedia.org/wiki/Computinghttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-3%23cite_note-3http://en.wikipedia.org/wiki/Metaphorhttp://en.wikipedia.org/wiki/Metaphorhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-4%23cite_note-4http://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Abstractionhttp://en.wikipedia.org/wiki/Abstractionhttp://en.wikipedia.org/wiki/Abstractionhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-5%23cite_note-5http://en.wikipedia.org/wiki/Business_applicationhttp://en.wikipedia.org/wiki/Web_browserhttp://en.wikipedia.org/wiki/Web_browserhttp://en.wikipedia.org/wiki/Web_browserhttp://en.wikipedia.org/wiki/Softwarehttp://en.wikipedia.org/wiki/Softwarehttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Server_(computing)http://en.wikipedia.org/wiki/Server_(computing)http://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Computinghttp://en.wikipedia.org/wiki/Paradigm_shifthttp://en.wikipedia.org/wiki/Mainframe_computerhttp://en.wikipedia.org/wiki/Client-serverhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-0%23cite_note-0http://en.wikipedia.org/wiki/Scalabilityhttp://en.wikipedia.org/wiki/Virtualizationhttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-gartner-1%23cite_note-gartner-1http://en.wikipedia.org/wiki/Cloud_computing#cite_note-really-2%23cite_note-really-2http://en.wikipedia.org/wiki/Computinghttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-3%23cite_note-3http://en.wikipedia.org/wiki/Metaphorhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-4%23cite_note-4http://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Abstractionhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-5%23cite_note-5http://en.wikipedia.org/wiki/Business_applicationhttp://en.wikipedia.org/wiki/Web_browserhttp://en.wikipedia.org/wiki/Softwarehttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Server_(computing)http://en.wikipedia.org/wiki/Cloud_computing#cite_note-csrc.nist.gov-6%23cite_note-csrc.nist.gov-6http://en.wikipedia.org/wiki/Cloud_computing#cite_note-csrc.nist.gov-6%23cite_note-csrc.nist.gov-6http://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Computinghttp://en.wikipedia.org/wiki/Paradigm_shifthttp://en.wikipedia.org/wiki/Mainframe_computerhttp://en.wikipedia.org/wiki/Client-serverhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-0%23cite_note-0http://en.wikipedia.org/wiki/Scalabilityhttp://en.wikipedia.org/wiki/Virtualizationhttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-gartner-1%23cite_note-gartner-1http://en.wikipedia.org/wiki/Cloud_computing#cite_note-really-2%23cite_note-really-2http://en.wikipedia.org/wiki/Computinghttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-3%23cite_note-3http://en.wikipedia.org/wiki/Metaphorhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-4%23cite_note-4http://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Computer_network_diagramhttp://en.wikipedia.org/wiki/Abstractionhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-5%23cite_note-5http://en.wikipedia.org/wiki/Business_applicationhttp://en.wikipedia.org/wiki/Web_browserhttp://en.wikipedia.org/wiki/Softwarehttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Server_(computing)8/7/2019 Cloud Computing is Internet
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A technical definition is "a computing capability that provides an abstraction between the
computing resource and its underlying technical architecture (e.g., servers, storage,
networks), enabling convenient, on-demand network access to a shared pool ofconfigurable computing resources that can be rapidly provisioned and released with
minimal management effort or service provider interaction."[7] This definition states that
clouds have five essential characteristics: on-demand self-service, broad network access,resource pooling, rapid elasticity, and measured service.[7]
Comparisons
Cloud computing derives characteristics from, but should not be confused with:
1. Autonomic computing "computer systems capable ofself-management".[9]
2. Client-server Client-server computing refers broadly to any distributed
applicationthat distinguishes between service providers (servers) and servicerequesters (clients).[10]
3. Grid computing "a form ofdistributed computing andparallel computing,whereby a 'super and virtual computer' is composed of a clusterof networked,loosely coupled computers acting in concert to perform very large tasks"
4. Mainframe powerful computers used mainly by large organizations for critical
applications, typically bulk data processing such ascensus, industry and consumer
statistics, enterprise resource planning, and financialtransaction processing.[11]5. Utility computing the "packaging ofcomputing resources, such as computation
and storage, as a metered service similar to a traditionalpublic utility, such as
electricity";[12]6. Peer-to-peer (disambiguation) systems in which data transfer utilizes the shared
resources of every system attached to the Intranet, setup for a specific task or
purpose (ie: BitTorrent (protocol) as one example of many which exists.)
[edit] Characteristics
In general, cloud computing customers do not own the physical infrastructure, instead
avoiding capital expenditure by renting usage from a third-party provider. They consumeresources as a service and pay only for resources that they use. Many cloud-computing
offerings employ the utility computing model, which is analogous to how traditional
utility services (such as electricity) are consumed, whereas others bill on asubscriptionbasis. Sharing "perishable and intangible" computing power among multiple tenants can
improve utilization rates, as servers are not unnecessarily left idle (which can reduce
costs significantly while increasing the speed of application development). A side-effectof this approach is that overall computer usage rises dramatically, as customers do nothave to engineer for peak load limits.[13] In addition, "increased high-speed bandwidth"
makes it possible to receive the same response times from centralized infrastructure at
other sites[14].
[edit] Economics
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.org/wiki/Cloud_computing#cite_note-13%23cite_note-13http://en.wikipedia.org/w/index.php?title=Cloud_computing&action=edit§ion=38/7/2019 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Cloud computing users can avoid capital expenditure(CapEx) on hardware, software,
and services when they pay a provider only for what they use. Consumption is usually
billed on a utility(resources consumed, like electricity) orsubscription (time-based, like anewspaper) basis with little or no upfront cost. Other benefits of this time sharing-style
approach are lowbarriers to entry, shared infrastructure and costs, low management
overhead, and immediate access to a broad range of applications. In general, users canterminate the contract at any time (thereby avoiding return on investmentrisk and
uncertainty), and the services are often covered by service level agreements (SLAs) with
financial penalties.[15][16]
According toNicholas Carr, the strategic importance ofinformation technologyisdiminishing as it becomes standardized and less expensive. He argues that the cloud
computingparadigm shift is similar to the displacement ofelectricity generators by
electricity grids early in the 20th century.[17]
Although companies might be able to save on upfront capital expenditures, they might
not save much and might actually pay more for operating expenses. In situations wherethe capital expense would be relatively small, or where the organization has more
flexibility in their capital budget than their operating budget, the cloud model might notmake great fiscal sense. Other factors impacting the scale of any potential cost savings
include the efficiency of a companys data center as compared to the cloud vendors, the
company's existing operating costs, the level of adoption of cloud computing, and thetype of functionality being hosted in the cloud.[18][19]
[edit] Architecture
Cloud computing sample architecture
Cloud architecture,[20] the systems architecture of thesoftware systems involved in thedelivery ofcloud computing, typically involves multiple cloud components
communicating with each other overapplication programming interfaces, usually web
services.[21]This resembles the Unix philosophy of having multiple programs each doing
one thing well and working together over universal interfaces. Complexity is controlledand the resulting systems are more manageable than theirmonolithiccounterparts.
[edit] History
The underlying concept of cloud computing dates back to1960, whenJohn McCarthyopined that "computation may someday be organized as apublic utility"; indeed it shares
characteristics with service bureausthat date back to the 1960s. The actual term "cloud"
borrows from telephony in that telecommunications companies, who until the 1990s
primarily offered dedicated point-to-point data circuits, began offeringVirtual PrivateNetwork(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 utilise their
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overall network bandwidth more effectively. The cloud symbol was used to denote the
demarcation point between that which was the responsibility of the provider from that of
the user. Cloud computing extends this boundary to cover servers as well as the networkinfrastructure.[22]
Amazon played a key role in the development of cloud computing by modernizing theirdata centers after thedot-com bubble, 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 easier, Amazon started providing access to their systems throughAmazon WebServices on a utility computing basis in2005.[23]
In 2007, Google,IBM, and a number of universities embarked on a large scale cloud
computing research project.[24]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",
[25]
and observed that "[o]rganisations are switchingfrom 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 ITproducts in some areas and significant reductions in other areas." [26]
[edit] Key features
Agility improves with users' ability to rapidly and inexpensively re-provision
technological infrastructure resources.[27]
Cost is claimed to be greatly reduced andcapital expenditureis converted to
operational expenditure[28] . This ostensibly lowersbarriers to entry, as
infrastructure is typically provided by a third-party and does not need to bepurchased 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).[29]
Device and location independence[30] enable users to access systems using a webbrowser regardless of their location or what device they are using (e.g., PC,
mobile). As infrastructure is off-site (typically provided by a third-party) and
accessed via the Internet, users can connect from anywhere.[29]
Multi-tenancy enables sharing of resources and costs across a large pool of users
thus allowing for:
o Centralization of infrastructure in locations with lower costs (such as real
estate, electricity, etc.)o Peak-load capacity increases (users need not engineer for highest
possible load-levels)o Utilization and efficiency improvements for systems that are often only
1020% utilized.[23]
Reliability improves through the use of multiple redundant sites, which makescloud computing suitable forbusiness continuity and disaster recovery.[31]
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Nonetheless, many major cloud computing services have suffered outages, and IT
and business managers can at times do little when they are affected.[32][33]
Scalability via dynamic ("on-demand")provisioning of resources on a fine-grained, self-service basis near real-time, without users having to engineer for
peak loads. Performanceis monitored, and consistent and loosely coupled
architectures are constructed using web services as the system interface.[29]
One ofthe most important new methods for overcoming performance bottlenecks for a
large class of applications is data parallel programming on a distributed data grid.[34]
Security could improve due to centralization of data[35], 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 [36]. Security is often as
good as or better than under traditional systems, in part because providers are ableto devote resources to solving security issues that many customers cannot afford.[37] Providers typically log accesses, but accessing theaudit logs themselves can be
difficult or impossible. Furthermore, the complexity of security is greatly
increased when data is distributed over a wider area and / or number of devices. Maintenance cloud computing applications are easier to maintain, since they
don't have to be installed on each user's computer. They are easier to support andto improve since the changes reach the clients instantly.
Metering cloud computing resources usage should be measurable and should be
metered per client and application on daily, weekly, monthly, and annual basis.
This will enable clients on choosing the vendor cloud on cost and reliability(QoS).
[edit] Layers
[edit] Client
See also: Category:Cloud clients
A cloud clientconsists ofcomputer hardware and/orcomputer softwarethat relies oncloud computing for application delivery, or that is specifically designed for delivery of
cloud services and that, in either case, is essentially useless without it. Examples include
somecomputers, phones and other devices, operating systems andbrowsers.[38][39][40][41][42]
[edit] Application
See also: Category:Cloud applications
Cloud application services or "Software as a Service (SaaS)" deliversoftware as a service
over the Internet, eliminating the need to install and run the application on the customer'sown computers and simplifying maintenance and support. Key characteristics include:[43]
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Network-based access to, and management of, commercially available (i.e., not
custom) software
Activities that are managed from central locations rather than at each customer'ssite, enabling customers to access applications remotely via the Web
Application delivery that typically is closer to a one-to-many model (single
instance, multi-tenant architecture) than to a one-to-one model, includingarchitecture, pricing, partnering, and management characteristics
Centralized feature updating, which obviates the need for downloadable patches
and upgrades.
[edit] Platform
See also: Category:Cloud platforms
Cloud platform services or "Platform as a Service (PaaS)" deliver a computing platformand/orsolution stackas a service, often consuming cloud infrastructure and sustaining
cloud applications. It facilitates deployment of applications without the cost andcomplexity of buying and managing the underlying hardware and software layers.[44][45]
[edit] Infrastructure
See also: Category:Cloud infrastructure
Cloud infrastructure services or "Infrastructure as a Service (IaaS)" delivers computer
infrastructure, typically aplatform virtualizationenvironment as a service. Rather thanpurchasing servers, software, data center space or network equipment, clients instead buy
those resources as a fully outsourced service. The service is typically billed on autility
computing basis and amount of resources consumed (and therefore the cost) will typicallyreflect the level of activity. It is an evolution ofvirtual private serverofferings.[46]
[edit] Server
Theservers layer consists ofcomputer hardwareand/orcomputer software products that
are specifically designed for the delivery of cloud services, including multi-core
processors, cloud-specific operating systems and combined offerings.[38][47][48][49]
[edit] Deployment models
Cloud computing types
Public cloudorexternal clouddescribes cloud computing in the traditional mainstreamsense, whereby resources are dynamically provisioned on a fine-grained, self-service
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basis over the Internet, via web applications/web services, from an off-site third-party
provider whoshares resources and bills on a fine-grainedutility computing basis.[29]
[edit] Community cloud
A community cloudmay be established where several organizations have similarrequirements and seek to share infrastructure so as to realize some of the benefits ofcloud computing. With the costs spread over fewer users than apublic cloud(but more
than a single tenant) this option is more expensive but may offer a higher level of
privacy, security and/or policy compliance. Examples ofcommunity cloudincludeGoogle's "Gov Cloud".[50]
[edit] Hybrid cloud
A hybrid cloudenvironment consisting of multiple internal and/or external providers[51]
"will be typical for most enterprises".[52] By integrating multiple cloud services users may
be able to ease the transition topublic cloudservices while avoiding issues such as PCIcompliance.[53]
Another perspective on deploying a web application in the cloud is using Hybrid Web
Hosting, where the hosting infrastructure is a mix between Cloud Hostingfor the web
server, and Managed dedicated serverfor the database server.[54]
[edit] Private cloud
Private cloudand internal cloudare neologismsthat some vendors have recently used todescribe offerings that emulate cloud computing on private networks. These (typically
virtualisationautomation) products claim to "deliver some benefits of cloud computingwithout the pitfalls", capitalising on data security, corporate governance, and reliabilityconcerns. They have been criticized on the basis that users "still have to buy, build, and
manage them" and as such do not benefit from lower up-front capital costs and less
hands-on management[52], essentially "[lacking] the economic model that makes cloudcomputing such an intriguing concept".[55][56]
[edit] Issues
[edit] 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 hostcompany. Instances such as the secretNSAprogram, 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.[57]While there have been efforts
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(such as US-EU Safe Harbor) to "harmonise" the legal environment, providers such as
Amazon still cater to major markets (typically the United Statesand the European Union)
by deploying local infrastructure and allowing customers to select "availability zones."[58]
[edit] Compliance
In order to obtain compliance with regulations including FISMA, HIPAA and SOX in theUS, the Data Protection Directive in theEU and the credit card industry's PCI DSS, users
may have to adopt community orhybriddeployment modes which are typically more
expensive and may offer restricted benefits. This is how Googleis able to "manage andmeet additional government policy requirements beyond FISMA"[59][60] and Rackspace
Cloud are able to claim PCI compliance.[61]
Many providers also obtain SAS 70 Type II certification (e.g. Amazon[62], Google[63] and
Microsoft[64]), but this has been criticised on the grounds that the hand-picked set of goalsand standards determined by the auditor and the auditee are often not disclosed and can
vary widely.[65]
Providers typically make this information available on request, undernon-disclosure agreement.[66]
[edit] Legal
In March 2007, Dell applied totrademarkthe term "cloud computing" (U.S. Trademark
77,139,082) in the United States. The "Notice of Allowance" the company received inJuly 2008 was cancelled 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 at an almost exponential rate.[67]
As companies sought to betterposition themselves for cloud computing branding and marketing efforts, cloud
computing trademark filings increased by 483% between 2008 and 2009. [68] In 2009, 116
cloud computing trademarks were filed, and trademark analysts predict that over 500such marks could be filed during 2010. [69]
[edit] Open source
Open standardsare critical to the growth of cloud computing, andopen source software
has provided the foundation for many cloud computing implementations.[70] In November
2007, the Free Software Foundation released the Affero General Public License, a
version ofGPLv3 intended to close a perceived legal loophole associated with freesoftwaredesigned to be run over a network.[71]
[edit] Open standards
See also: Category:Cloud standards
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ttp://en.wikipedia.org/wiki/Dellhttp://en.wikipedia.org/wiki/Trademarkhttp://tarr.uspto.gov/servlet/tarr?regser=serial&entry=77139082http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=77139082http://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-66%23cite_note-66http://en.wikipedia.org/wiki/Cloud_computing#cite_note-67%23cite_note-67http://en.wikipedia.org/wiki/Cloud_computing#cite_note-68%23cite_note-68http://en.wikipedia.org/w/index.php?title=Cloud_computing&action=edit§ion=21http://en.wikipedia.org/wiki/Open_standardshttp://en.wikipedia.org/wiki/Open_source_softwarehttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-69%23cite_note-69http://en.wikipedia.org/wiki/Free_Software_Foundationhttp://en.wikipedia.org/wiki/Affero_General_Public_Licensehttp://en.wikipedia.org/wiki/GNU_General_Public_Licensehttp://en.wikipedia.org/wiki/Legal_technicalityhttp://en.wikipedia.org/wiki/Free_softwarehttp://en.wikipedia.org/wiki/Free_softwarehttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-70%23cite_note-70http://en.wikipedia.org/w/index.php?title=Cloud_computing&action=edit§ion=22http://en.wikipedia.org/wiki/Category:Cloud_standards8/7/2019 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Most cloud providers expose APIs which are typically well-documented (often under a
Creative Commons license[72]) however also unique to their implementation and thus not
interoperable. Some vendors have adopted others' APIs[73] and there are a number ofopenstandardsunder development, including theOGF'sOpen Cloud Computing Interface.
The Open Cloud Consortium (OCC) [74] is working to develop consensus on early cloud
computing standards and practices.
[edit] Security
The relative security of cloud computing services is a contentious issue which may bedelaying its adoption.[75]Some argue that customer data is more secure when managed
internally, while others argue that cloud providers have a strong incentive to maintain
trust and as such employ a higher level of security.[76]
[edit] Sustainability
Although cloud computing is often assumed to be a form of "green computing", there isas of yet no published study to substantiate this assumption.
Comparisons
Cloud computing derives characteristics from, but should not be confused with:
1. Autonomic computing "computer systems capable ofself-management".[9]2. Client-server Client-server computing refers broadly to any distributed
applicationthat distinguishes between service providers (servers) and service
requesters (clients).[10]
3. Grid computing "a form ofdistributed computing andparallel computing,whereby a 'super and virtual computer' is composed of a clusterof networked,
loosely coupled computers acting in concert to perform very large tasks"4. Mainframe powerful computers used mainly by large organizations for critical
applications, typically bulk data processing such ascensus, industry and consumer
statistics, enterprise resource planning, and financialtransaction processing.[11]
5. Utility computing the "packaging ofcomputing resources, such as computationand storage, as a metered service similar to a traditionalpublic utility, such as
electricity";[12]
6. Peer-to-peer (disambiguation) systems in which data transfer utilizes the sharedresources of every system attached to the Intranet, setup for a specific task or
purpose (ie: BitTorrent (protocol) as one example of many which exists.)
[edit] Characteristics
In general, cloud computing customers do not own the physical infrastructure, instead
avoiding capital expenditure by renting usage from a third-party provider. They consume
resources as a service and pay only for resources that they use. Many cloud-computingofferings employ the utility computing model, which is analogous to how traditional
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0http://en.wikipedia.org/wiki/Utility_computinghttp://en.wikipedia.org/wiki/Computational_resourcehttp://en.wikipedia.org/wiki/Public_utilityhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-It.27s_probable_that_you.E2.80.99ve_misunderstood_.E2.80.9CCloud_Computing.E2.80.9D_till_now-11%23cite_note-It.27s_probable_that_you.E2.80.99ve_misunderstood_.E2.80.9CCloud_Computing.E2.80.9D_till_now-11http://en.wikipedia.org/wiki/Peer-to-peer_(disambiguation)http://en.wikipedia.org/wiki/Intranethttp://en.wikipedia.org/wiki/BitTorrent_(protocol)http://en.wikipedia.org/w/index.php?title=Cloud_computing&action=edit§ion=2http://en.wikipedia.org/wiki/Capital_expenditurehttp://en.wikipedia.org/w/index.php?title=Everything_as_a_service&action=edit&redlink=1http://en.wikipedia.org/wiki/Utility_computing8/7/2019 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utility services (such as electricity) are consumed, whereas others bill on asubscription
basis. Sharing "perishable and intangible" computing power among multiple tenants can
improve utilization rates, as servers are not unnecessarily left idle (which can reducecosts significantly while increasing the speed of application development). A side-effect
of this approach is that overall computer usage rises dramatically, as customers do not
have to engineer for peak load limits.[13]
In addition, "increased high-speed bandwidth"makes it possible to receive the same response times from centralized infrastructure at
other sites[14].
[edit] Economics
Cloud computing users can avoid capital expenditure(CapEx) on hardware, software,
and services when they pay a provider only for what they use. Consumption is usuallybilled on a utility(resources consumed, like electricity) orsubscription (time-based, like a
newspaper) basis with little or no upfront cost. Other benefits of this time sharing-style
approach are lowbarriers to entry, shared infrastructure and costs, low management
overhead, and immediate access to a broad range of applications. In general, users canterminate the contract at any time (thereby avoiding return on investmentrisk and
uncertainty), and the services are often covered by service level agreements (SLAs) with
financial penalties.[15][16]
According toNicholas Carr, the strategic importance ofinformation technologyisdiminishing as it becomes standardized and less expensive. He argues that the cloud
computingparadigm shift is similar to the displacement ofelectricity generators by
electricity grids early in the 20th century.[17]
Although companies might be able to save on upfront capital expenditures, they might
not save much and might actually pay more for operating expenses. In situations wherethe capital expense would be relatively small, or where the organization has more
flexibility in their capital budget than their operating budget, the cloud model might notmake great fiscal sense. Other factors impacting the scale of any potential cost savings
include the efficiency of a companys data center as compared to the cloud vendors, the
company's existing operating costs, the level of adoption of cloud computing, and thetype of functionality being hosted in the cloud.[18][19]
[edit] Architecture
Cloud computing sample architecture
Cloud architecture,[20] the systems architecture of thesoftware systems involved in the
delivery ofcloud computing, typically involves multiple cloud components
communicating with each other overapplication programming interfaces, usually web
services.[21]This resembles the Unix philosophy of having multiple programs each doing
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one thing well and working together over universal interfaces. Complexity is controlled
and the resulting systems are more manageable than theirmonolithiccounterparts.
[edit] History
The underlying concept of cloud computing dates back to1960, whenJohn McCarthyopined that "computation may someday be organized as apublic utility"; indeed it shares
characteristics with service bureausthat date back to the 1960s. The actual term "cloud"
borrows from telephony in that telecommunications companies, who until the 1990sprimarily offered dedicated point-to-point data circuits, began offeringVirtual 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 utilise theiroverall network bandwidth more effectively. The cloud symbol was used to denote the
demarcation point between that which was the responsibility of the provider from that of
the user. Cloud computing extends this boundary to cover servers as well as the networkinfrastructure.[22]
Amazon played a key role in the development of cloud computing by modernizing their
data centers after thedot-com bubble, 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 easier, Amazon started providing access to their systems throughAmazon Web
Services on a utility computing basis in2005.[23]
In 2007, Google,IBM, and a number of universities embarked on a large scale cloud
computing research project.[24]By mid-2008, Gartner saw an opportunity for cloud
computing "to shape the relationship among consumers of IT services, those who use ITservices and those who sell them",[25] and observed that "[o]rganisations 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." [26]
[edit] Key features
Agility improves with users' ability to rapidly and inexpensively re-provision
technological infrastructure resources.[27]
Cost is claimed to be greatly reduced andcapital expenditureis converted tooperational expenditure[28] . This ostensibly lowersbarriers 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 autility computing basis is fine-grained with usage-based options and fewer IT
skills are required for implementation (in-house).[29]
Device and location independence[30] enable users to access systems using a webbrowser regardless of their location or what device they are using (e.g., PC,
http://en.wikipedia.org/wiki/Monolithic_systemhttp://en.wikipedia.org/wiki/Monolithic_systemhttp://en.wikipedia.org/w/index.php?title=Cloud_computing&action=edit§ion=5http://en.wikipedia.org/wiki/1960http://en.wikipedia.org/wiki/1960http://en.wikipedia.org/wiki/John_McCarthy_(computer_scientist)http://en.wikipedia.org/wiki/John_McCarthy_(computer_scientist)http://en.wikipedia.org/wiki/Public_utilityhttp://en.wikipedia.org/wiki/Service_bureauhttp://en.wikipedia.org/wiki/Service_bureauhttp://en.wikipedia.org/wiki/Telephonyhttp://en.wikipedia.org/wiki/Virtual_Private_Networkhttp://en.wikipedia.org/wiki/Virtual_Private_Networkhttp://en.wikipedia.org/wiki/Virtual_Private_Networkhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-21%23cite_note-21http://en.wikipedia.org/wiki/Amazon.comhttp://en.wikipedia.org/wiki/Data_centerhttp://en.wikipedia.org/wiki/Dot-com_bubblehttp://en.wikipedia.org/wiki/Dot-com_bubblehttp://en.wikipedia.org/wiki/Dot-com_bubblehttp://en.wikipedia.org/wiki/Computer_networkshttp://en.wikipedia.org/wiki/Computer_networkshttp://en.wikipedia.org/wiki/Amazon_Web_Serviceshttp://en.wikipedia.org/wiki/Amazon_Web_Serviceshttp://en.wikipedia.org/wiki/Amazon_Web_Serviceshttp://en.wikipedia.org/wiki/Utility_computinghttp://en.wikipedia.org/wiki/2005http://en.wikipedia.org/wiki/2005http://en.wikipedia.org/wiki/Cloud_computing#cite_note-amazon-22%23cite_note-amazon-22http://en.wikipedia.org/wiki/Cloud_computing#cite_note-amazon-22%23cite_note-amazon-22http://en.wikipedia.org/wiki/2007http://en.wikipedia.org/wiki/Googlehttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-23%23cite_note-23http://en.wikipedia.org/wiki/Cloud_computing#cite_note-23%23cite_note-23http://en.wikipedia.org/wiki/Cloud_computing#cite_note-23%23cite_note-23http://en.wikipedia.org/wiki/Cloud_computing#cite_note-24%23cite_note-24http://en.wikipedia.org/wiki/Cloud_computing#cite_note-24%23cite_note-24http://en.wikipedia.org/wiki/Cloud_computing#cite_note-25%23cite_note-25http://en.wikipedia.org/w/index.php?title=Cloud_computing&action=edit§ion=6http://en.wikipedia.org/wiki/Agilityhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-26%23cite_note-26http://en.wikipedia.org/wiki/Cloud_computing#cite_note-26%23cite_note-26http://en.wikipedia.org/wiki/Cloud_computing#cite_note-26%23cite_note-26http://en.wikipedia.org/wiki/Costhttp://en.wikipedia.org/wiki/Capital_expenditurehttp://en.wikipedia.org/wiki/Capital_expenditurehttp://en.wikipedia.org/wiki/Capital_expenditurehttp://en.wikipedia.org/wiki/Operational_expenditurehttp://en.wikipedia.org/wiki/Operational_expenditurehttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-27%23cite_note-27http://en.wikipedia.org/wiki/Cloud_computing#cite_note-27%23cite_note-27http://en.wikipedia.org/wiki/Cloud_computing#cite_note-27%23cite_note-27http://en.wikipedia.org/wiki/Barriers_to_entryhttp://en.wikipedia.org/wiki/Utility_computinghttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-idc-28%23cite_note-idc-28http://en.wikipedia.org/wiki/Cloud_computing#cite_note-idc-28%23cite_note-idc-28http://en.wikipedia.org/wiki/Cloud_computing#cite_note-idc-28%23cite_note-idc-28http://en.wikipedia.org/wiki/Device_independencehttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-yarmis-29%23cite_note-yarmis-29http://en.wikipedia.org/wiki/Monolithic_systemhttp://en.wikipedia.org/w/index.php?title=Cloud_computing&action=edit§ion=5http://en.wikipedia.org/wiki/1960http://en.wikipedia.org/wiki/John_McCarthy_(computer_scientist)http://en.wikipedia.org/wiki/Public_utilityhttp://en.wikipedia.org/wiki/Service_bureauhttp://en.wikipedia.org/wiki/Telephonyhttp://en.wikipedia.org/wiki/Virtual_Private_Networkhttp://en.wikipedia.org/wiki/Virtual_Private_Networkhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-21%23cite_note-21http://en.wikipedia.org/wiki/Amazon.comhttp://en.wikipedia.org/wiki/Data_centerhttp://en.wikipedia.org/wiki/Dot-com_bubblehttp://en.wikipedia.org/wiki/Computer_networkshttp://en.wikipedia.org/wiki/Amazon_Web_Serviceshttp://en.wikipedia.org/wiki/Amazon_Web_Serviceshttp://en.wikipedia.org/wiki/Utility_computinghttp://en.wikipedia.org/wiki/2005http://en.wikipedia.org/wiki/Cloud_computing#cite_note-amazon-22%23cite_note-amazon-22http://en.wikipedia.org/wiki/2007http://en.wikipedia.org/wiki/Googlehttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-23%23cite_note-23http://en.wikipedia.org/wiki/Cloud_computing#cite_note-24%23cite_note-24http://en.wikipedia.org/wiki/Cloud_computing#cite_note-25%23cite_note-25http://en.wikipedia.org/w/index.php?title=Cloud_computing&action=edit§ion=6http://en.wikipedia.org/wiki/Agilityhttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-26%23cite_note-26http://en.wikipedia.org/wiki/Costhttp://en.wikipedia.org/wiki/Capital_expenditurehttp://en.wikipedia.org/wiki/Operational_expenditurehttp://en.wikipedia.org/wiki/Cloud_computing#cite_note-27%23cite_note-27http://en.wiki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mobile). As infrastructure is off-site (typically provided by a third-party) and
accessed via the Internet, users can connect from anywhere.[29]
Multi-tenancy enables sharing of resources and costs across a large pool of usersthus allowing for:
o Centralization of infrastructure in locations with lower costs (such as real
estate, electricity, etc.)o Peak-load capacity increases (users need not engineer for highest
possible load-levels)
o Utilization and efficiency improvements for systems that are often only
1020% utilized.[23]
Reliability improves through the use of multiple redundant sites, which makes
cloud computing suitable forbusiness continuity and disaster recovery.[31]
Nonetheless, many major cloud computing services have suffered outages, and IT
and business managers can at times do little when they are affected.[32][33]
Scalability via dynamic ("on-demand")provisioning of resources on a fine-
grained, self-service basis near real-time, without users having to engineer for
peak loads. Performanceis monitored, and consistent and loosely coupledarchitectures are constructed using web services as the system interface.[29] One of
the most important new methods for overcoming performance bottlenecks for alarge class of applications is data parallel programming on a distributed data grid.[34]
Security could improve due to centralization of data[35], 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 [36]. Security is often as
good as or better than under traditional systems, in part because providers are ableto devote resources to solving security issues that many customers cannot afford.[37] Providers typically log accesses, but accessing theaudit logs themselves can be
difficult or impossible. Furthermore, the complexity of security is greatlyincreased when data is distributed over a wider area and / or number of devices. Maintenance cloud computing applications are easier to maintain, since they
don't have to be installed on each user's computer. They are easier to support and
to improve since the changes reach the clients instantly.
Metering cloud computing resources usage should be measurable and should be
metered per client and application on daily, weekly, monthly, and annual basis.
This will enable clients on choosing the vendor cloud on cost and reliability(QoS).
[edit] Layers
[edit] Client
See also: Category:Cloud clients
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