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Grid Computing And CloudComputing: Study

ContentsArticles

Grid computing 1Cloud computing 9

ReferencesArticle Sources and Contributors 25Image Sources, Licenses and Contributors 27

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Grid computing 1

Grid computingGrid computing is the federation of computer resources from multiple administrative domains to reach a commongoal. The grid can be thought of as a distributed system with non-interactive workloads that involve a large numberof files. What distinguishes grid computing from conventional high performance computing systems such as clustercomputing is that grids tend to be more loosely coupled, heterogeneous, and geographically dispersed.[1] Although asingle grid can be dedicated to a particular application, commonly a grid is used for a variety of purposes. Grids areoften constructed with general-purpose grid middleware software libraries.Grid size varies a considerable amount. Grids are a form of distributed computing whereby a “super virtualcomputer” is composed of many networked loosely coupled computers acting together to perform large tasks. Forcertain applications, “distributed” or “grid” computing, can be seen as a special type of parallel computing that relieson complete computers (with onboard CPUs, storage, power supplies, network interfaces, etc.) connected to anetwork (private, public or the Internet) by a conventional network interface, such as Ethernet. This is in contrast tothe traditional notion of a supercomputer, which has many processors connected by a local high-speed computer bus.

OverviewA grid computer is multiple number of same class of computers clustered together. A grid computer is connectedthrough a super fast network and share the devices like disk drives, mass storage, printers and RAM Grid Computingis a cost efficient solution with respect to Super Computing. Operating system has capability of parallelismGrid computing combines computers from multiple administrative domains to reach a common goal,[2] to solve asingle task, and may then disappear just as quickly.One of the main strategies of grid computing is to use middleware to divide and apportion pieces of a programamong several computers, sometimes up to many thousands. Grid computing involves computation in a distributedfashion, which may also involve the aggregation of large-scale cluster computing-based systems.The size of a grid may vary from small—confined to a network of computer workstations within a corporation, forexample—to large, public collaborations across many companies and networks. "The notion of a confined grid mayalso be known as an intra-nodes cooperation whilst the notion of a larger, wider grid may thus refer to an inter-nodescooperation".[3]

Grids are a form of distributed computing whereby a “super virtual computer” is composed of many networkedloosely coupled computers acting together to perform very large tasks. This technology has been applied tocomputationally intensive scientific, mathematical, and academic problems through volunteer computing, and it isused in commercial enterprises for such diverse applications as drug discovery, economic forecasting, seismicanalysis, and back office data processing in support for e-commerce and Web services.Coordinating applications on Grids can be a complex task, especially when coordinating the flow of informationacross distributed computing resources. Grid workflow systems have been developed as a specialized form of aworkflow management system designed specifically to compose and execute a series of computational or datamanipulation steps, or a workflow, in the Grid context.

Grid computing 2

Comparison of grids and conventional supercomputers“Distributed” or “grid” computing in general is a special type of parallel computing that relies on complete computers(with onboard CPUs, storage, power supplies, network interfaces, etc.) connected to a network (private, public or theInternet) by a conventional network interface, such as Ethernet. This is in contrast to the traditional notion of asupercomputer, which has many processors connected by a local high-speed computer bus.The primary advantage of distributed computing is that each node can be purchased as commodity hardware, which,when combined, can produce a similar computing resource as multiprocessor supercomputer, but at a lower cost.This is due to the economies of scale of producing commodity hardware, compared to the lower efficiency ofdesigning and constructing a small number of custom supercomputers. The primary performance disadvantage is thatthe various processors and local storage areas do not have high-speed connections. This arrangement is thuswell-suited to applications in which multiple parallel computations can take place independently, without the need tocommunicate intermediate results between processors.[4] The high-end scalability of geographically dispersed gridsis generally favorable, due to the low need for connectivity between nodes relative to the capacity of the publicInternet.There are also some differences in programming and deployment. It can be costly and difficult to write programs thatcan run in the environment of a supercomputer, which may have a custom operating system, or require the programto address concurrency issues. If a problem can be adequately parallelized, a “thin” layer of “grid” infrastructure canallow conventional, standalone programs, given a different part of the same problem, to run on multiple machines.This makes it possible to write and debug on a single conventional machine, and eliminates complications due tomultiple instances of the same program running in the same shared memory and storage space at the same time.

Design considerations and variationsOne feature of distributed grids is that they can be formed from computing resources belonging to multipleindividuals or organizations (known as multiple administrative domains). This can facilitate commercialtransactions, as in utility computing, or make it easier to assemble volunteer computing networks.One disadvantage of this feature is that the computers which are actually performing the calculations might not beentirely trustworthy. The designers of the system must thus introduce measures to prevent malfunctions or maliciousparticipants from producing false, misleading, or erroneous results, and from using the system as an attack vector.This often involves assigning work randomly to different nodes (presumably with different owners) and checkingthat at least two different nodes report the same answer for a given work unit. Discrepancies would identifymalfunctioning and malicious nodes.Due to the lack of central control over the hardware, there is no way to guarantee that nodes will not drop out of thenetwork at random times. Some nodes (like laptops or dialup Internet customers) may also be available forcomputation but not network communications for unpredictable periods. These variations can be accommodated byassigning large work units (thus reducing the need for continuous network connectivity) and reassigning work unitswhen a given node fails to report its results in expected time.The impacts of trust and availability on performance and development difficulty can influence the choice of whetherto deploy onto a dedicated computer cluster, to idle machines internal to the developing organization, or to an openexternal network of volunteers or contractors. In many cases, the participating nodes must trust the central systemnot to abuse the access that is being granted, by interfering with the operation of other programs, mangling storedinformation, transmitting private data, or creating new security holes. Other systems employ measures to reduce theamount of trust “client” nodes must place in the central system such as placing applications in virtual machines.Public systems or those crossing administrative domains (including different departments in the same organization) often result in the need to run on heterogeneous systems, using different operating systems and hardware architectures. With many languages, there is a trade off between investment in software development and the number

Grid computing 3

of platforms that can be supported (and thus the size of the resulting network). Cross-platform languages can reducethe need to make this trade off, though potentially at the expense of high performance on any given node (due torun-time interpretation or lack of optimization for the particular platform). There are diverse scientific andcommercial projects to harness a particular associated grid or for the purpose of setting up new grids. BOINC is acommon one for various academic projects seeking public volunteers; more are listed at the end of the article.In fact, the middleware can be seen as a layer between the hardware and the software. On top of the middleware, anumber of technical areas have to be considered, and these may or may not be middleware independent. Exampleareas include SLA management, Trust and Security, Virtual organization management, License Management, Portalsand Data Management. These technical areas may be taken care of in a commercial solution, though the cutting edgeof each area is often found within specific research projects examining the field.

Market segmentation of the grid computing marketFor the segmentation of the grid computing market, two perspectives need to be considered: the provider side and theuser side:

The provider sideThe overall grid market comprises several specific markets. These are the grid middleware market, the market forgrid-enabled applications, the utility computing market, and the software-as-a-service (SaaS) market.Grid middleware is a specific software product, which enables the sharing of heterogeneous resources, and VirtualOrganizations. It is installed and integrated into the existing infrastructure of the involved company or companies,and provides a special layer placed among the heterogeneous infrastructure and the specific user applications. Majorgrid middlewares are Globus Toolkit, gLite, and UNICORE.Utility computing is referred to as the provision of grid computing and applications as service either as an open gridutility or as a hosting solution for one organization or a VO. Major players in the utility computing market are SunMicrosystems, IBM, and HP.Grid-enabled applications are specific software applications that can utilize grid infrastructure. This is made possibleby the use of grid middleware, as pointed out above.Software as a service (SaaS) is “software that is owned, delivered and managed remotely by one or more providers.”(Gartner 2007) Additionally, SaaS applications are based on a single set of common code and data definitions. Theyare consumed in a one-to-many model, and SaaS uses a Pay As You Go (PAYG) model or a subscription model thatis based on usage. Providers of SaaS do not necessarily own the computing resources themselves, which are requiredto run their SaaS. Therefore, SaaS providers may draw upon the utility computing market. The utility computingmarket provides computing resources for SaaS providers.

The user sideFor companies on the demand or user side of the grid computing market, the different segments have significantimplications for their IT deployment strategy. The IT deployment strategy as well as the type of IT investments madeare relevant aspects for potential grid users and play an important role for grid adoption.

CPU scavengingCPU-scavenging, cycle-scavenging, cycle stealing, or shared computing creates a “grid” from the unused resources in a network of participants (whether worldwide or internal to an organization). Typically this technique uses desktop computer instruction cycles that would otherwise be wasted at night, during lunch, or even in the scattered seconds throughout the day when the computer is waiting for user input or slow devices. In practice, participating computers also donate some supporting amount of disk storage space, RAM, and network bandwidth,

Grid computing 4

in addition to raw CPU power.Many Volunteer computing projects, such as BOINC, use the CPU scavenging model. Since nodes are likely to go"offline" from time to time, as their owners use their resources for their primary purpose, this model must bedesigned to handle such contingencies.[5]

HistoryThe term grid computing originated in the early 1990s as a metaphor for making computer power as easy to accessas an electric power grid. The power grid metaphor for accessible computing quickly became canonical when IanFoster and Carl Kesselman published their seminal work, "The Grid: Blueprint for a new computing infrastructure"(2004).CPU scavenging and volunteer computing were popularized beginning in 1997 by distributed.net and later in 1999by SETI@home to harness the power of networked PCs worldwide, in order to solve CPU-intensive researchproblems.The ideas of the grid (including those from distributed computing, object-oriented programming, and Web services)were brought together by Ian Foster, Carl Kesselman, and Steve Tuecke, widely regarded as the "fathers of thegrid".[6] They led the effort to create the Globus Toolkit incorporating not just computation management but alsostorage management, security provisioning, data movement, monitoring, and a toolkit for developing additionalservices based on the same infrastructure, including agreement negotiation, notification mechanisms, triggerservices, and information aggregation. While the Globus Toolkit remains the de facto standard for building gridsolutions, a number of other tools have been built that answer some subset of services needed to create an enterpriseor global grid.In 2007 the term cloud computing came into popularity, which is conceptually similar to the canonical Fosterdefinition of grid computing (in terms of computing resources being consumed as electricity is from the power grid).Indeed, grid computing is often (but not always) associated with the delivery of cloud computing systems asexemplified by the AppLogic system from 3tera.

Fastest virtual supercomputers• BOINC – 7.279 PFLOPS as of December 24, 2012.[7]

• Folding@Home – 4.195 PFLOPS, as of December 24, 2009[8]

• As of April 2010, MilkyWay@Home computes at over 1.6 PFLOPS, with a large amount of this work comingfrom GPUs.[9]

• As of April 2010, SETI@Home computes data averages more than 730 TFLOPS.[10]

• As of April 2010, Einstein@Home is crunching more than 210 TFLOPS.[11]

• As of June 2011, GIMPS is sustaining 61 TFLOPS.[12]

Grid computing 5

Projects and applicationsGrids computing offer a way to solve Grand Challenge problems such as protein folding, financial modeling,earthquake simulation, and climate/weather modeling. Grids offer a way of using the information technologyresources optimally inside an organization. They also provide a means for offering information technology as autility for commercial and noncommercial clients, with those clients paying only for what they use, as withelectricity or water.Grid computing is being applied by the National Science Foundation's National Technology Grid, NASA'sInformation Power Grid, Pratt & Whitney, Bristol-Myers Squibb Co., and American Express.One cycle-scavenging networks is SETI@home, which was using more than 3 million computers to achieve 23.37sustained teraflops (979 lifetime teraflops) as of September 2001.[13]

As of August 2009 Folding@home achieves more than 4 petaflops on over 350,000 machines.The European Union funded projects through the framework programmes of the European Commission. BEinGRID(Business Experiments in Grid) was a research project funded by the European Commission[14] as an IntegratedProject under the Sixth Framework Programme (FP6) sponsorship program. Started on June 1, 2006, the project ran42 months, until November 2009. The project was coordinated by Atos Origin. According to the project fact sheet,their mission is “to establish effective routes to foster the adoption of grid computing across the EU and to stimulateresearch into innovative business models using Grid technologies”. To extract best practice and common themesfrom the experimental implementations, two groups of consultants are analyzing a series of pilots, one technical, onebusiness. The project is significant not only for its long duration, but also for its budget, which at 24.8 million Euros,is the largest of any FP6 integrated project. Of this, 15.7 million is provided by the European commission and theremainder by its 98 contributing partner companies. Since the end of the project, the results of BEinGRID have beentaken up and carried forward by IT-Tude.com [15].The Enabling Grids for E-sciencE project, based in the European Union and included sites in Asia and the UnitedStates, was a follow-up project to the European DataGrid (EDG) and evoled into the European Grid Infrastructure.This, along with the LHC Computing Grid[16] (LCG), was developed to support experiments using the CERN LargeHadron Collider. The A list of active sites participating within LCG can be found online[17] as can real timemonitoring of the EGEE infrastructure.[18] The relevant software and documentation is also publicly accessible.[19]

There is speculation that dedicated fiber optic links, such as those installed by CERN to address the LCG'sdata-intensive needs, may one day be available to home users thereby providing internet services at speeds up to10,000 times faster than a traditional broadband connection.[20]

The distributed.net project was started in 1997. The NASA Advanced Supercomputing facility (NAS) ran geneticalgorithms using the Condor cycle scavenger running on about 350 Sun Microsystems and SGI workstations.In 2001, United Devices operated the United Devices Cancer Research Project based on its Grid MP product, whichcycle-scavenges on volunteer PCs connected to the Internet. The project ran on about 3.1 million machines before itsclose in 2007.[21]

As of 2011, over 6.2 million machines running the open-source Berkeley Open Infrastructure for NetworkComputing (BOINC) platform are members of the World Community Grid, which tops the processing power of thecurrent fastest supercomputer system (China's Tianhe-I).[22]

Grid computing 6

DefinitionsToday there are many definitions of grid computing:• In his article “What is the Grid? A Three Point Checklist”,[2] Ian Foster lists these primary attributes:

• Computing resources are not administered centrally.• Open standards are used.• Nontrivial quality of service is achieved.

• Plaszczak/Wellner[23] define grid technology as "the technology that enables resource virtualization, on-demandprovisioning, and service (resource) sharing between organizations."

• IBM defines grid computing as “the ability, using a set of open standards and protocols, to gain access toapplications and data, processing power, storage capacity and a vast array of other computing resources over theInternet. A grid is a type of parallel and distributed system that enables the sharing, selection, and aggregation ofresources distributed across ‘multiple’ administrative domains based on their (resources) availability, capacity,performance, cost and users' quality-of-service requirements”.[24]

• An earlier example of the notion of computing as utility was in 1965 by MIT's Fernando Corbató. Corbató and theother designers of the Multics operating system envisioned a computer facility operating “like a power companyor water company”.[25]

• Buyya/Venugopal[26] define grid as "a type of parallel and distributed system that enables the sharing, selection,and aggregation of geographically distributed autonomous resources dynamically at runtime depending on theiravailability, capability, performance, cost, and users' quality-of-service requirements".

• CERN, one of the largest users of grid technology, talk of The Grid: “a service for sharing computer power anddata storage capacity over the Internet.”[27]

Grids can be categorized with a three stage model of departmental grids, enterprise grids and global grids. Thesecorrespond to a firm initially utilising resources within a single group i.e. an engineering department connectingdesktop machines, clusters and equipment. This progresses to enterprise grids where nontechnical staff's computingresources can be used for cycle-stealing and storage. A global grid is a connection of enterprise and departmentalgrids that can be used in a commercial or collaborative manner.

See also•• Jungle computing

References[1] http:/ / www. e-sciencecity. org/ EN/ gridcafe/ what-is-the-grid. html[2] "What is the Grid? A Three Point Checklist" (http:/ / dlib. cs. odu. edu/ WhatIsTheGrid. pdf). .[3] "Pervasive and Artificial Intelligence Group :: publications [Pervasive and Artificial Intelligence Research Group]" (http:/ / diuf. unifr. ch/

pai/ wiki/ doku. php?id=Publications& page=publication& kind=single& ID=276). Diuf.unifr.ch. May 18, 2009. . Retrieved July 29, 2010.[4] http:/ / www. e-sciencecity. org/ EN/ gridcafe/ computational-problems. html[5][5] Kamran Karimi, Neil G. Dickson, and Firas Hamze, High-Performance Physics Simulations Using Multi-Core CPUs and GPGPUs in a

Volunteer Computing Context, International Journal of High Performance Computing Applications, 2011[6] "Father of the Grid" (http:/ / magazine. uchicago. edu/ 0404/ features/ index. shtml). .[7] " BOINCstats – BOINC combined credit overview (http:/ / boincstats. com/ en/ stats/ -1/ project/ detail)." Retrieved on 24 December 2012.[8] (http:/ / fah-web. stanford. edu/ cgi-bin/ main. py?qtype=osstats). Retrieved 24 December 2012.[9] "MilkyWay@Home Credit overview" (http:/ / boincstats. com/ en/ stats/ 61/ project/ detail). BOINC. . Retrieved April 21, 2010.[10] "SETI@Home Credit overview" (http:/ / boincstats. com/ en/ stats/ 0/ project/ detail). BOINC. . Retrieved April 21, 2010.[11] "Einstein@Home Credit overview" (http:/ / boincstats. com/ en/ stats/ 5/ project/ detail). BOINC. . Retrieved April 21, 2010.[12] "Internet PrimeNet Server Distributed Computing Technology for the Great Internet Mersenne Prime Search" (http:/ / www. mersenne. org/

primenet). GIMPS. . Retrieved June 6, 2011[13] (http:/ / setiathome. ssl. berkeley. edu/ totals. html)[14] Home page of BEinGRID (http:/ / www. beingrid. eu/ )[15] http:/ / www. it-tude. com

Grid computing 7

[16] Large Hadron Collider Computing Grid official homepage (http:/ / lcg. web. cern. ch/ LCG/ )[17] "GStat 2.0 – Summary View – GRID EGEE" (http:/ / goc. grid. sinica. edu. tw/ gstat/ ). Goc.grid.sinica.edu.tw. . Retrieved July 29, 2010.[18] "Real Time Monitor" (http:/ / gridportal. hep. ph. ic. ac. uk/ rtm/ ). Gridportal.hep.ph.ic.ac.uk. . Retrieved July 29, 2010.[19] "LCG – Deployment" (http:/ / lcg. web. cern. ch/ LCG/ activities/ deployment. html). Lcg.web.cern.ch. . Retrieved July 29, 2010.[20] "Coming soon: superfast internet" (http:/ / www. timesonline. co. uk/ tol/ news/ science/ article3689881. ece)[21] (http:/ / www. grid. org/ stats/ )[22] BOINCstats (http:/ / boincstats. com)[23] P Plaszczak, R Wellner, Grid computing, 2005, Elsevier/Morgan Kaufmann, San Francisco[24][24] IBM Solutions Grid for Business Partners: Helping IBM Business Partners to Grid-enable applications for the next phase of e-business on

demand[25] http:/ / www. multicians. org/ fjcc3. html[26] "A Gentle Introduction to Grid Computing and Technologies" (http:/ / www. buyya. com/ papers/ GridIntro-CSI2005. pdf) (PDF). .

Retrieved May 6, 2005.[27] "The Grid Café – The place for everybody to learn about grid computing" (http:/ / www. gridcafe. org). CERN. . Retrieved December 3,

2008.

Bibliography• Buyya, Rajkumar; Kris Bubendorfer (2009). Market Oriented Grid and Utility Computing (http:/ / www. wiley.

com/ WileyCDA/ WileyTitle/ productCd-0470287683,descCd-tableOfContents. html). Wiley.ISBN 978-0-470-28768-2.

• Benedict, Shajulin; Vasudevan (2008). "A Niched Pareto GA approach for scheduling scientific workflows inwireless Grids". Journal of Computing and Information Technology 16: 101.

• Davies, Antony (June 2004). "Computational Intermediation and the Evolution of Computation as a Commodity"(http:/ / www. business. duq. edu/ faculty/ davies/ research/ EconomicsOfComputation. pdf) (PDF). AppliedEconomics 36 (11): 1131. doi:10.1080/0003684042000247334.

• Foster, Ian; Carl Kesselman (1999). The Grid: Blueprint for a New Computing Infrastructure (http:/ / www. mkp.com/ grids/ ). Morgan Kaufmann Publishers. ISBN 1-55860-475-8.

• Plaszczak, Pawel; Rich Wellner, Jr (2006). Grid Computing "The Savvy Manager's Guide" (http:/ / savvygrid.com/ ). Morgan Kaufmann Publishers. ISBN 0-12-742503-9.

• Berman, Fran; Anthony J. G. Hey, Geoffrey C. Fox (2003). Grid Computing: Making The Global Infrastructure aReality (http:/ / www. grid2002. org/ ). Wiley. ISBN 0-470-85319-0.

• Li, Maozhen; Mark A. Baker (2005). The Grid: Core Technologies (http:/ / coregridtechnologies. org/ ). Wiley.ISBN 0-470-09417-6.

• Catlett, Charlie; Larry Smarr (June 1992). "Metacomputing" (http:/ / www. acm. org/ pubs/ cacm/ ).Communications of the ACM 35 (6).

• Smith, Roger (2005). "Grid Computing: A Brief Technology Analysis" (http:/ / www. ctonet. org/ documents/GridComputing_analysis. pdf) (PDF). CTO Network Library.

• Buyya, Rajkumar (July 2005). "Grid Computing: Making the Global Cyberinfrastructure for eScience a Reality"(http:/ / www. gridbus. org/ ~raj/ papers/ CSICommunicationsJuly2005. pdf) (PDF). CSI Communications(Mumbai, India: Computer Society of India (CSI)) 29 (1).

• Berstis, Viktors. "Fundamentals of Grid Computing" (http:/ / www. redbooks. ibm. com/ abstracts/ redp3613.html). IBM.

• Ferreira, Luis; et al.. "Grid Computing Products and Services" (http:/ / www. redbooks. ibm. com/ abstracts/sg246650. html). IBM.

• Ferreira, Luis; et al.. "Introduction to Grid Computing with Globus" (http:/ / www. redbooks. ibm. com/ abstracts/sg246895. html?Open). IBM.

• Jacob, Bart; et al.. "Enabling Applications for Grid Computing" (http:/ / www. redbooks. ibm. com/ abstracts/sg246936. html?Open). IBM.

• Ferreira, Luis; et al.. "Grid Services Programming and Application Enablement" (http:/ / www. redbooks. ibm.com/ abstracts/ sg246100. html?Open). IBM.

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• Jacob, Bart; et al.. "Introduction to Grid Computing" (http:/ / www. redbooks. ibm. com/ abstracts/ sg246778.html?Open). IBM.

• Ferreira, Luis; et al.. "Grid Computing in Research and Education" (http:/ / www. redbooks. ibm. com/ abstracts/sg246649. html?Open). IBM.

• Ferreira, Luis; et al.. "Globus Toolkit 3.0 Quick Start" (http:/ / www. redbooks. ibm. com/ abstracts/ redp3697.html?Open). IBM.

• Surridge, Mike; et al.. "Experiences with GRIA – Industrial applications on a Web Services Grid" (http:/ / www.gria. org/ docs/ experiences with gria paper. pdf) (PDF). IEEE.

• Stockinger, Heinz; et al. (to be published in 2007). "Defining the Grid: A Snapshot on the Current View" (http:/ /hst. web. cern. ch/ hst/ publications/ DefiningTheGrid-1. 1. pdf) (PDF). Supercomputing 42: 3.doi:10.1007/s11227-006-0037-9.

• Global Grids and Software Toolkits: A Study of Four Grid Middleware Technologies (http:/ / www. gridbus. org/~raj/ papers/ gmchapter. pdf)

• The Grid Technology Cookbook (http:/ / hv3. phys. lsu. edu:8000/ cookbook/ gtcb/ index. php)• Francesco Lelli, Eric Frizziero, Michele Gulmini, Gaetano Maron, Salvatore Orlando, Andrea Petrucci and

Silvano Squizzato. The many faces of the integration of instruments and the grid. International Journal of Weband Grid Services 2007 – Vol. 3, No.3 pp. 239 – 266 Electronic Edition (http:/ / www. inderscience. com/ search/index. php?action=record& rec_id=14953& prevQuery=& ps=10& m=or)

• Poess, Meikel; Nambiar, Raghunath (2005). Large Scale Data Warehouses on Grid (http:/ / www. vldb2005. org/program/ paper/ tue/ p1055-poess. pdf).

• Pardi, Silvio; Francesco Palmieri (October 2010). "Towards a federated Metropolitan Area Grid environment:The SCoPE network-aware infrastructure" (http:/ / www. sciencedirect. com/ science/ article/ pii/S0167739X10000191). Future Generation Computer Systems 26. doi:10.1016/j.future.2010.02.0039.

External links• GridCafé (http:/ / www. e-sciencecity. org/ gridcafe)—an layperson's introduction to grid computing and how it

works• SuGI-Portal (http:/ / sugi. dgrid. de/ )—more on grids.• The Open Source GridTask Project link (http:/ / programmingmore. blogspot. com/ 2010/ 12/

gridtask-project-java-php-javascript. html)• (http:/ / people. na. infn. it/ ~spardi/ )—Metropolitan Area Grid.

Cloud computing 9

Cloud computing

Cloud computing logical diagram

Cloud computing is the use ofcomputing resources (hardware andsoftware) that are delivered as aservice over a network (typically theInternet). The name comes from theuse of a cloud-shaped symbol as anabstraction for the complexinfrastructure it contains in systemdiagrams. Cloud computing entrustsremote services with a user's data,software and computation.

There are many types of public cloudcomputing:[1]

• Infrastructure as a service (IaaS)• Platform as a service (PaaS)• Software as a service (SaaS)• Network as a service (NaaS)• Storage as a service (STaaS)• Security as a service (SECaaS)• Data as a service (DaaS)•• Database as a service (DBaaS)• Test environment as a service (TEaaS)•• Desktop virtualization• API as a service (APIaaS)• Backend as a service (BaaS)In the business model using software as a service, users are provided access to application software and databases.The cloud providers manage the infrastructure and platforms on which the applications run. SaaS is sometimesreferred to as “on-demand software” and is usually priced on a pay-per-use basis. SaaS providers generally priceapplications using a subscription fee.Proponents claim that the SaaS allows a business the potential to reduce IT operational costs by outsourcinghardware and software maintenance and support to the cloud provider. This enables the business to reallocate IToperations costs away from hardware/software spending and personnel expenses, towards meeting other IT goals. Inaddition, with applications hosted centrally, updates can be released without the need for users to install newsoftware. One drawback of SaaS is that the users' data are stored on the cloud provider’s server. As a result, therecould be unauthorized access to the data.End users access cloud-based applications through a web browser or a light-weight desktop or mobile app while thebusiness software and user's data are stored on servers at a remote location. Proponents claim that cloud computingallows enterprises to get their applications up and running faster, with improved manageability and less maintenance,and enables IT to more rapidly adjust resources to meet fluctuating and unpredictable business demand.[2][3]

Cloud computing relies on sharing of resources to achieve coherence and economies of scale similar to a utility (likethe electricity grid) over a network.[4] At the foundation of cloud computing is the broader concept of convergedinfrastructure and shared services.

Cloud computing 10

HistoryThe origin of the term cloud computing is obscure, but it appears to derive from the practice of using drawings ofstylized clouds to denote networks in diagrams of computing and communications systems. The word cloud is usedas a metaphor for the Internet, based on the standardized use of a cloud-like shape to denote a network on telephonyschematics and later to depict the Internet in computer network diagrams as an abstraction of the underlyinginfrastructure it represents. The cloud symbol was used to represent the Internet as early as 1994.[5][6]

The underlying concept of cloud computing dates back to the 1950s, when large-scale mainframe became availablein academia and corporations, accessible via thin clients / terminal computers. Because it was costly to buy amainframe, it became important to find ways to get the greatest return on the investment in them, allowing multipleusers to share both the physical access to the computer from multiple terminals as well as to share the CPU time,eliminating periods of inactivity, which became known in the industry as time-sharing.[7]

In the 1990s, telecommunications companies, who previously offered primarily dedicated point-to-point datacircuits, began offering virtual private network (VPN) services with comparable quality of service but at a muchlower cost. By switching traffic to balance utilization as they saw fit, they were able to utilize their overall networkbandwidth more effectively. The cloud symbol was used to denote the demarcation point between that which was theresponsibility of the provider and that which was the responsibility of the users. Cloud computing extends thisboundary to cover servers as well as the network infrastructure.[8]

As computers became more prevalent, scientists and technologists explored ways to make large-scale computingpower available to more users through time sharing, experimenting with algorithms to provide the optimal use of theinfrastructure, platform and applications with prioritized access to the CPU and efficiency for the end users.[9]

John McCarthy opined in the 1960s that "computation may someday be organized as a public utility." Almost all themodern-day characteristics of cloud computing (elastic provision, provided as a utility, online, illusion of infinitesupply), 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. Other scholarshave shown that cloud computing's roots go all the way back to the 1950s when scientist Herb Grosch (the author ofGrosch's law) postulated that the entire world would operate on dumb terminals powered by about 15 large datacenters.[10] Due to the expense of these powerful computers, many corporations and other entities could availthemselves of computing capability through time sharing and several organizations, such as GE's GEISCO, IBMsubsidiary The Service Bureau Corporation (SBC, founded in 1957), Tymshare (founded in 1966), National CSS(founded in 1967 and bought by Dun & Bradstreet in 1979), Dial Data (bought by Tymshare in 1968), and Bolt,Beranek and Newman (BBN) marketed time sharing as a commercial venture.The development of the Internet from being document centric via semantic data towards more and more services wasdescribed as "Dynamic Web".[11] This contribution focused in particular in the need for better meta-data able todescribe not only implementation details but also conceptual details of model-based applications.The ubiquitous availability of high-capacity networks, low-cost computers and storage devices as well as thewidespread adoption of hardware virtualization, service-oriented architecture, autonomic, and utility computing haveled to a tremendous growth in cloud computing.[12][13][14]

After the dot-com bubble, Amazon played a key role in the development of cloud computing by modernizing theirdata centers, which, like most computer networks, were using as little as 10% of their capacity at any one time, justto leave room for occasional spikes. Having found that the new cloud architecture resulted in significant internalefficiency improvements whereby small, fast-moving "two-pizza teams" (teams small enough to be fed with twopizzas) could add new features faster and more easily, Amazon initiated a new product development effort to providecloud computing to external customers, and launched Amazon Web Service (AWS) on a utility computing basis in2006.[15][16]

Cloud computing 11

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 firstopen-source software for deploying private and hybrid clouds, and for the federation of clouds.[17] In the same year,efforts were focused on providing quality of service guarantees (as required by real-time interactive applications) tocloud-based infrastructures, in the framework of the IRMOS European Commission-funded project, resulting to areal-time cloud environment.[18] By mid-2008, Gartner saw an opportunity for cloud computing "to shape therelationship among consumers of IT services, those who use IT services and those who sell them"[19] and observedthat "organizations are switching from company-owned hardware and software assets to per-use service-basedmodels" so that the "projected shift to computing... will result in dramatic growth in IT products in some areas andsignificant reductions in other areas."[20]

On March 1, 2011, IBM announced the Smarter Computing framework to support Smarter Planet.[21] Among thevarious components of the Smarter Computing foundation, cloud computing is a critical piece.

Similar systems and conceptsCloud computing shares characteristics with:• Autonomic computing — Computer systems capable of self-management.[22]

• Client–server model — Client–server computing refers broadly to any distributed application that distinguishesbetween service providers (servers) and service requesters (clients).[23]

• Grid computing — "A form of distributed and parallel computing, whereby a 'super and virtual computer' iscomposed 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, police and secret intelligenceservices, enterprise resource planning, and financial transaction processing.[24]

• Utility computing — The "packaging of computing resources, such as computation and storage, as a meteredservice similar to a traditional public utility, such as electricity."[25][26]

• Peer-to-peer — Distributed architecture without the need for central coordination, with participants being at thesame time both suppliers and consumers of resources (in contrast to the traditional client–server model).

• Cloud gaming - Also known as on-demand gaming, this is a way of delivering games to computers. The gamingdata will be stored in the provider's server, so that gaming will be independent of client computers used to playthe game.

CharacteristicsCloud 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. Cloudcomputing systems typically use REST-based APIs.

• Cost is claimed to be reduced and in a public cloud delivery model capital expenditure is converted to operationalexpenditure.[27] This is purported to lower barriers to entry, as infrastructure is typically provided by a third-partyand does not need to be purchased for one-time or infrequent intensive computing tasks. Pricing on a utilitycomputing basis is fine-grained with usage-based options and fewer IT skills are required for implementation(in-house).[28] The e-FISCAL project's state of the art repository[29] contains several articles looking into costaspects in more detail, most of them concluding that costs savings depend on the type of activities supported andthe type of infrastructure available in-house.

• Device and location independence[30] 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

Cloud computing 12

a third-party) and accessed via the Internet, users can connect from anywhere.[28]

• Virtualization technology allows servers and storage devices to be shared and utilization be increased.Applications can be easily migrated from one physical server to another.

• Multitenancy 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)• Utilisation and efficiency improvements for systems that are often only 10–20% utilised.[15]

• Reliability is improved if multiple redundant sites are used, which makes well-designed cloud computing suitablefor business continuity and disaster recovery.[31]

• Scalability and elasticity via dynamic ("on-demand") provisioning of resources on a fine-grained, self-servicebasis near real-time,[32] without users having to engineer for peak loads.[33][34]

• Performance is monitored, and consistent and loosely coupled architectures are constructed using web servicesas the system interface.[28]

• Security could improve due to centralization of data, increased security-focused resources, etc., but concerns canpersist about loss of control over certain sensitive data, and the lack of security for stored kernels.[35] Security isoften as good as or better than other traditional systems, in part because providers are able to devote resources tosolving security issues that many customers cannot afford.[36] However, the complexity of security is greatlyincreased when data is distributed over a wider area or greater number of devices and in multi-tenant systems thatare being shared by unrelated users. In addition, user access to security audit logs may be difficult or impossible.Private cloud installations are in part motivated by users' desire to retain control over the infrastructure and avoidlosing control of information security.

• Maintenance of cloud computing applications is easier, because they do not need to be installed on each user'scomputer and can be accessed from different places.

The National Institute of Standards and Technology's definition of cloud computing identifies "five essentialcharacteristics":

On-demand self-service. A consumer can unilaterally provision computing capabilities, such as server timeand network storage, as needed automatically without requiring human interaction with each service provider.Broad network access. Capabilities are available over the network and accessed through standard mechanismsthat promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, tablets, laptops, andworkstations).Resource pooling. The provider’s computing resources are pooled to serve multiple consumers using amulti-tenant model, with different physical and virtual resources dynamically assigned and reassignedaccording to consumer demand. ...Rapid elasticity. Capabilities can be elastically provisioned and released, in some cases automatically, to scalerapidly outward and inward commensurate with demand. To the consumer, the capabilities available forprovisioning often appear to be unlimited and can be appropriated in any quantity at any time.Measured service. Cloud systems automatically control and optimize resource use by leveraging a meteringcapability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth,and active user accounts). Resource usage can be monitored, controlled, and reported, providing transparencyfor both the provider and consumer of the utilized service.—National Institute of Standards and Technology[4]

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On-demand self-serviceOn-demand self-service allows users to obtain, configure and deploy cloud services themselves using cloud servicecatalogues, without requiring the assistance of IT.[37][38] This feature is listed by the National Institute of Standardsand Technology (NIST) as a characteristic of cloud computing.[4]

The self-service requirement of cloud computing prompts infrastructure vendors to create cloud computingtemplates, which are obtained from cloud service catalogues. Manufacturers of such templates or blueprints includeHewlett-Packard (HP), which names its templates as HP Cloud Maps[39] RightScale[40] and Red Hat, which namesits templates CloudForms.[41]

The templates contain predefined configurations used by consumers to set up cloud services. The templates orblueprints provide the technical information necessary to build ready-to-use clouds.[40] Each template includesspecific configuration details for different cloud infrastructures, with information about servers for specific taskssuch as hosting applications, databases, websites and so on.[40] The templates also include predefined Web service,the operating system, the database, security configurations and load balancing.[41]

Cloud consumers use cloud templates to move applications between clouds through a self-service portal. Thepredefined blueprints define all that an application requires to run in different environments. For example, a templatecould define how the same application could be deployed in cloud platforms based on Amazon Web Service,VMware or Red Hat.[42] The user organization benefits from cloud templates because the technical aspects of cloudconfigurations reside in the templates, letting users to deploy cloud services with a push of a button.[43][44] Cloudtemplates can also be used by developers to create a catalog of cloud services.[45]

Service modelsCloud computing providers offer their services according to three fundamental models:[4][46] infrastructure as aservice (IaaS), platform as a service (PaaS), and software as a service (SaaS) where IaaS is the most basic and eachhigher model abstracts from the details of the lower models. In 2012 network as a service (NaaS) andcommunication as a service (CaaS) were officially included by ITU (International Telecommunication Union) aspart of the basic cloud computing models, recognized service categories of a telecommunication-centric cloudecosystem.[47]

Infrastructure as a service (IaaS)

In this most basic cloud service model, IaaS providers offer computers,as physical or more often as virtual machines, and other resources. Thevirtual machines are run as guests by a hypervisor, such as Xen orKVM. Pools of hypervisors within the cloud operational supportsystem support large numbers of virtual machines and the ability toscale services up and down according to customers' varyingrequirements. IaaS clouds often offer additional resources such asimages in a virtual machine image library, raw (block) and file-basedstorage, firewalls, load balancers, IP addresses, virtual local areanetworks (VLANs), and software bundles.[48] IaaS cloud providerssupply these resources on demand from their large pools installed in data centers. For wide area connectivity, theInternet can be used or—in carrier clouds—dedicated virtual private networks can be configured.

To deploy their applications, cloud users install operating system images and their application software on the cloudinfrastructure. In this model, it is the cloud user who is responsible for patching and maintaining the operatingsystems and application software. Cloud providers typically bill IaaS services on a utility computing basis, that is,cost reflects the amount of resources allocated and consumed.

Cloud computing 14

Examples of IaaS providers include Amazon CloudFormation, Amazon EC2, Windows Azure Virtual Machines,DynDNS, Google Compute Engine, HP Cloud, Joyent, Rackspace Cloud, ReadySpace Cloud Services, andTerremark.

Platform as a service (PaaS)In the PaaS model, cloud providers deliver a computing platform typically including operating system, programminglanguage execution environment, database, and web server. Application developers can develop and run theirsoftware solutions on a cloud platform without the cost and complexity of buying and managing the underlyinghardware and software layers. With some PaaS offers, the underlying computer and storage resources scaleautomatically to match application demand such that cloud user does not have to allocate resources manually.Examples of PaaS include: Amazon Elastic Beanstalk, Cloud Foundry, Heroku, Force.com, EngineYard, Mendix,Google App Engine, Windows Azure Compute and OrangeScape.

Software as a service (SaaS)In the SaaS model, cloud providers install and operate application software in the cloud and cloud users access thesoftware from cloud clients. The cloud users do not manage the cloud infrastructure and platform on which theapplication is running. This eliminates the need to install and run the application on the cloud user's own computerssimplifying maintenance and support. What makes a cloud application different from other applications is itsscalability. This can be achieved by cloning tasks onto multiple virtual machines at run-time to meet the changingwork demand.[49] Load balancers distribute the work over the set of virtual machines. This process is transparent tothe cloud user who sees only a single access point. To accommodate a large number of cloud users, cloudapplications can be multitenant, that is, any machine serves more than one cloud user organization. It is common torefer to special types of cloud based application software with a similar naming convention: desktop as a service,business process as a service, test environment as a service, communication as a service.The pricing model for SaaS applications is typically a monthly or yearly flat fee per user,[50] so price is scalable andadjustable if users are added or removed at any point.[51]

Examples of SaaS include: Google Apps, Microsoft Office 365, Onlive, GT Nexus, Marketo, and TradeCard.

Network as a service (NaaS)A category of cloud services where the capability provided to the cloud service user is to use network/transportconnectivity services and/or inter-cloud network connectivity services.[52] NaaS involves the optimization ofresource allocations by considering network and computing resources as a unified whole.[53]

Traditional NaaS services include flexible and extended VPN, and bandwidth on demand.[52] NaaS conceptmaterialization also includes the provision of a virtual network service by the owners of the network infrastructure toa third party (VNP – VNO).[54][55]

Cloud clientsUsers access cloud computing using networked client devices, such as desktop computers, laptops, tablets and smartphones. Some of these devices - cloud clients - rely on cloud computing for all or a majority of their applications so as to be essentially useless without it. Examples are thin clients and the browser-based Chromebook. Many cloud applications do not require specific software on the client and instead use a web browser to interact with the cloud application. With Ajax and HTML5 these Web user interfaces can achieve a similar or even better look and feel as native applications. Some cloud applications, however, support specific client software dedicated to these applications (e.g., virtual desktop clients and most email clients). Some legacy applications (line of business applications that until now have been prevalent in thin client Windows computing) are delivered via a screen-sharing

Cloud computing 15

technology.

Deployment models

Cloud computing types

Public cloud

Public cloud applications, storage, andother resources are made available tothe general public by a serviceprovider. These services are free oroffered on a pay-per-use model.Generally, public cloud serviceproviders like Amazon AWS,Microsoft and Google own and operatethe infrastructure and offer access onlyvia Internet (direct connectivity is notoffered).[28]

Community cloudCommunity cloud shares infrastructure between several organizations from a specific community with commonconcerns (security, compliance, jurisdiction, etc.), whether managed internally or by a third-party and hostedinternally or externally. The costs are spread over fewer users than a public cloud (but more than a private cloud), soonly some of the cost savings potential of cloud computing are realized.[4]

Hybrid cloudHybrid cloud is a composition of two or more clouds (private, community or public) that remain unique entities butare bound together, offering the benefits of multiple deployment models.[4]

By utilizing "hybrid cloud" architecture, companies and individuals are able to obtain degrees of fault tolerancecombined with locally immediate usability without dependency on internet connectivity. Hybrid cloud architecturerequires both on-premises resources and off-site (remote) server-based cloud infrastructure.Hybrid clouds lack the flexibility, security and certainty of in-house applications.[56] Hybrid cloud provides theflexibility of in house applications with the fault tolerance and scalability of cloud based services.

Private cloudPrivate cloud is cloud infrastructure operated solely for a single organization, whether managed internally or by athird-party and hosted internally or externally.[4] Undertaking a private cloud project requires a significant level anddegree of engagement to virtualize the business environment, and it will require the organization to reevaluatedecisions about existing resources. When it is done right, it can have a positive impact on a business, but every oneof the steps in the project raises security issues that must be addressed in order to avoid serious vulnerabilities.[57]

They have attracted criticism because users "still have to buy, build, and manage them" and thus do not benefit fromless hands-on management,[58] essentially "[lacking] the economic model that makes cloud computing such anintriguing concept".[59][60]

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Architecture

Cloud computing sample architecture

Cloud architecture,[61] the systemsarchitecture of the software systemsinvolved in the delivery of cloudcomputing, typically involves multiplecloud components communicating witheach other over a loose couplingmechanism such as a messaging queue.Elastic provision implies intelligencein the use of tight or loose coupling asapplied to mechanisms such as theseand others.

The Intercloud

The Intercloud[62] is an interconnectedglobal "cloud of clouds"[63][64] and anextension of the Internet "network of networks" on which it is based.[65][66][67]

Cloud engineeringCloud engineering is the application of engineering disciplines to cloud computing. It brings a systematic approachto the high-level concerns of commercialisation, standardisation, and governance in conceiving, developing,operating and maintaining cloud computing systems. It is a multidisciplinary method encompassing contributionsfrom diverse areas such as systems, software, web, performance, information, security, platform, risk, and qualityengineering.

Issues

PrivacyThe cloud model has been criticized by privacy advocates for the greater ease in which the companies hosting thecloud services control, thus, can monitor at will, whether permitted or not by their customers, the communicationbetween the host company and her end-user, as well as her stored data. Instances such as the secret NSA program,working with AT&T, and Verizon, which recorded over 10 million telephone calls between American citizens,causes uncertainty among privacy advocates, and the greater powers it gives to telecommunication companies tomonitor user activity.[68] Using a cloud service provider (CSP) can complicate privacy of data because of the extentto which virtualization for cloud processing (virtual machines) and cloud storage are used to implement cloudservice.[69] CSP operations, customer or tenant data may not remain on the same system, or in the same data centeror even within the same provider's cloud; this can lead to legal concerns over jurisdiction. While there have beenefforts (such as US-EU Safe Harbor) to "harmonise" the legal environment, providers such as Amazon still cater tomajor markets (typically the United States and the European Union) by deploying local infrastructure and allowingcustomers to select "availability zones."[70] Cloud computing poses privacy concerns because the service providermay access the data that is on the cloud at any point in time. They could accidentally or deliberately alter or evendelete information.[71]

Postage and delivery services company Pitney Bowes launched Volly, a cloud-based, digital mailbox service to leverage its communication management assets. They also faced the technical challenge of providing strong data security and privacy. However, they were able to address the same concern by applying customized,

Cloud computing 17

application-level security, including encryption. [72]

ComplianceIn order to obtain compliance with regulations including FISMA, HIPAA, and SOX in the United States, the DataProtection Directive in the EU and the credit card industry's PCI DSS, users may have to adopt community or hybriddeployment 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"[73][74] and Rackspace Cloud orQubeSpace are able to claim PCI compliance.[75]

Many providers also obtain a SAS 70 Type II audit, but this has been criticised on the grounds that the hand-pickedset of goals and standards determined by the auditor and the auditee are often not disclosed and can vary widely.[76]

Providers typically make this information available on request, under non-disclosure agreement.[77][78]

Customers in the EU contracting with cloud providers outside the EU/EEA have to adhere to the EU regulations onexport of personal data.[79]

U.S. Federal Agencies have been directed by the Office of Management and Budget to use a process calledFedRAMP (Federal Risk and Authorization Management Program) to assess and authorize cloud products andservices. Federal CIO Steven VanRoekel issued a memorandum to federal agency Chief Information Officers onDecember 8, 2011 defining how federal agencies should use FedRAMP. FedRAMP consists of a subset of NISTSpecial Publication 800-53 security controls specifically selected to provide protection in cloud environments. Asubset has been defined for the FIPS 199 low categorization and the FIPS 199 moderate categorization. TheFedRAMP program has also established a Joint Accreditation Board (JAB) consisting of Chief Information Officersfrom DoD, DHS and GSA. The JAB is responsible for establishing accreditation standards for 3rd partyorganizations who will perform the assessments of cloud solutions. The JAB will also review authorization packagesand may grant provisional authorization (to operate). The federal agency consuming the service will still have thefinal responsibility for final authority to operate.[80]

LegalAs with other changes in the landscape of computing, certain legal issues arise with cloud computing, includingtrademark infringement, security concerns and sharing of propriety data resources.The Electronic Frontier Foundation has criticized the United States government for considering during theMegaupload seizure process that people lose property rights by storing data on a cloud computing service.[81]

One important but not often mentioned problem with cloud computing is the problem of whom is in "possession" ofthe data. If a cloud company is the possessor of the data, the possessor has certain legal rights. If the cloud companyis the "custodian" of the data, then a different set of rights would apply. The next problem in the legalities of cloudcomputing is the problem of legal ownership of the data. Many Terms of Service agreements are silent on thequestion of ownership.[82]

Cloud computing 18

Open sourceOpen-source software has provided the foundation for many cloud computing implementations, prominent examplesbeing the Hadoop framework[83] and VMware's Cloud Foundry.[84] In November 2007, the Free SoftwareFoundation released the Affero General Public License, a version of GPLv3 intended to close a perceived legalloophole associated with free software designed to be run over a network.[85]

Open standardsMost cloud providers expose APIs that are typically well-documented (often under a Creative Commons license[86])but also unique to their implementation and thus not interoperable. Some vendors have adopted others' APIs andthere are a number of open standards under development, with a view to delivering interoperability andportability.[87] As of November 2012, the Open Standard with broadest industry support is probably OpenStack,founded in 2010 by NASA and Rackspace, and now governed by the OpenStack Foundation.[88] OpenStacksupporters include AMD, Intel, Canonical, SUSE Linux, Red Hat, Cisco, Dell, HP, IBM, Yahoo and nowVMware.[89]

SecurityAs cloud computing is achieving increased popularity, concerns are being voiced about the security issuesintroduced through adoption of this new model. The effectiveness and efficiency of traditional protectionmechanisms are being reconsidered as the characteristics of this innovative deployment model can differ widelyfrom those of traditional architectures.[90] An alternative perspective on the topic of cloud security is that this is butanother, although quite broad, case of "applied security" and that similar security principles that apply in sharedmulti-user mainframe security models apply with cloud security.[91]

The relative security of cloud computing services is a contentious issue that may be delaying its adoption.[92]

Physical control of the Private Cloud equipment is more secure than having the equipment off site and undersomeone else’s control. Physical control and the ability to visually inspect the data links and access ports is requiredin order to ensure data links are not compromised. Issues barring the adoption of cloud computing are due in largepart to the private and public sectors' unease surrounding the external management of security-based services. It isthe very nature of cloud computing-based services, private or public, that promote external management of providedservices. This delivers great incentive to cloud computing service providers to prioritize building and maintainingstrong management of secure services.[93] Security issues have been categorised into sensitive data access, datasegregation, 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 (PKI), to use of multiple cloud providers, standardisation of APIs, andimproving virtual machine support and legal support.[90][94][95]

Cloud computing offers many benefits, but it also is vulnerable to threats. As the uses of cloud computing increase, itis highly likely that more criminals will try to find new ways to exploit vulnerabilities in the system. There are manyunderlying challenges and risks in cloud computing that increase the threat of data being compromised. To helpmitigate the threat, cloud computing stakeholders should invest heavily in risk assessment to ensure that the systemencrypts to protect data; establishes trusted foundation to secure the platform and infrastructure; and builds higherassurance into auditing to strengthen compliance. Security concerns must be addressed in order to establish trust incloud computing technology.

Cloud computing 19

SustainabilityAlthough cloud computing is often assumed to be a form of "green computing", there is no published study tosubstantiate this assumption.[96] Citing the servers' affects on the environmental effects of cloud computing, in areaswhere climate favors natural cooling and renewable electricity is readily available, the environmental effects will bemore moderate. (The same holds true for "traditional" data centers.) Thus countries with favorable conditions, suchas Finland,[97] Sweden and Switzerland,[98] are trying to attract cloud computing data centers. Energy efficiency incloud computing can result from energy-aware scheduling and server consolidation.[99] However, in the case ofdistributed clouds over data centers with different source of energies including renewable source of energies, a smallcompromise on energy consumption reduction could result in high carbon footprint reduction.[100]

AbuseAs with privately purchased hardware, customers can purchase the services of cloud computing for nefariouspurposes. This includes password cracking and launching attacks using the purchased services.[101] In 2009, abanking trojan illegally used the popular Amazon service as a command and control channel that issued softwareupdates and malicious instructions to PCs that were infected by the malware.[102]

IT governanceThe introduction of cloud computing requires an appropriate IT governance model to ensure a secured computingenvironment and to comply with all relevant organizational information technology policies.[103][104] As such,organizations need a set of capabilities that are essential when effectively implementing and managing cloudservices, including demand management, relationship management, data security management, application lifecyclemanagement, risk and compliance management.[105]

ResearchMany universities, vendors and government organizations are investing in research around the topic of cloudcomputing:[106][107]

• In October 2007, the Academic Cloud Computing Initiative (ACCI) was announced as a multi-university projectdesigned to enhance students' technical knowledge to address the challenges of cloud computing.[108]

• In April 2009, UC Santa Barbara released the first open source platform-as-a-service, AppScale, which is capableof running Google App Engine applications at scale on a multitude of infrastructures.

• In April 2009, the St Andrews Cloud Computing Co-laboratory was launched, focusing on research in theimportant new area of cloud computing. Unique in the UK, StACC aims to become an international centre ofexcellence for research and teaching in cloud computing and will provide advice and information to businessesinterested in using cloud-based services.[109]

• In October 2010, the TClouds (Trustworthy Clouds) project was started, funded by the European Commission's7th Framework Programme. The project's goal is to research and inspect the legal foundation and architecturaldesign to build a resilient and trustworthy cloud-of-cloud infrastructure on top of that. The project also develops aprototype to demonstrate its results.[110]

• In December 2010, the TrustCloud research project [111][112] was started by HP Labs Singapore to addresstransparency and accountability of cloud computing via detective, data-centric approaches[113] encapsulated in afive-layer TrustCloud Framework. The team identified the need for monitoring data life cycles and transfers in thecloud,[111] leading to the tackling of key cloud computing security issues such as cloud data leakages, cloudaccountability and cross-national data transfers in transnational clouds.

•• In July 2011, the High Performance Computing Cloud (HPCCLoud) project was kicked-off aiming at finding outthe possibilities of enhancing performance on cloud environments while running the scientific applications -

Cloud computing 20

development of HPCCLoud Performance Analysis Toolkit which was funded by CIM-Returning ExpertsProgramme - under the coordination of Prof. Dr. Shajulin Benedict.

• In June 2011, the Telecommunications Industry Association developed a Cloud Computing White Paper, toanalyze the integration challenges and opportunities between cloud services and traditional U.S.telecommunications standards.[114]

References[1] Monaco, Ania (7 June 2012 [last update]). "A View Inside the Cloud" (http:/ / theinstitute. ieee. org/ technology-focus/ technology-topic/

a-view-inside-the-cloud). theinstitute.ieee.org (IEEE). . Retrieved August 21, 2012.[2] "Baburajan, Rajani, "The Rising Cloud Storage Market Opportunity Strengthens Vendors," infoTECH, August 24, 2011" (http:/ / it. tmcnet.

com/ channels/ cloud-storage/ articles/ 211183-rising-cloud-storage-market-opportunity-strengthens-vendors. htm). It.tmcnet.com.2011-08-24. . Retrieved 2011-12-02.

[3] "Oestreich, Ken, "Converged Infrastructure," CTO Forum, November 15, 2010" (http:/ / www. thectoforum. com/ content/converged-infrastructure-0). Thectoforum.com. 2010-11-15. . Retrieved 2011-12-02.

[4] "The NIST Definition of Cloud Computing" (http:/ / csrc. nist. gov/ publications/ nistpubs/ 800-145/ SP800-145. pdf). National Institute ofScience and Technology. . Retrieved 24 July 2011.

[5] Figure 8, "A network […] is shown schematically as a cloud", U.S. Patent 5,485,455 (http:/ / www. google. com/ patents?vid=5485455),column 17, line 22, filed Jan 28, 1994

[6] Figure 1, "the cloud indicated at 49 in Fig. 1.", U.S. Patent 5,790,548 (http:/ / www. google. com/ patents?vid=5790548), column 5 lines56-57, filed April 18, 1996

[7] Strachey, Christopher (June 1959). "Time Sharing in Large Fast Computers". Proceedings of the International Conference on Informationprocessing, UNESCO. paper B.2.19: 336–341.

[8] "July, 1993 meeting report from the IP over ATM working group of the IETF" (http:/ / mirror. switch. ch/ ftp/ doc/ ietf/ ipatm/atm-minutes-93jul. txt). CH: Switch. . Retrieved 2010-08-22.

[9] Corbató, Fernando J.. "An Experimental Time-Sharing System" (http:/ / larch-www. lcs. mit. edu:8001/ ~corbato/ sjcc62/ ). SJCCProceedings. MIT. . Retrieved 3 July 2012.

[10] Ryan; Falvey; Merchant (October 2011), "Regulation of the Cloud in India" (http:/ / ssrn. com/ abstract=1941494), Journal of Internet Law15 (4),

[11][11] Andreas Tolk. 2006. What Comes After the Semantic Web - PADS Implications for the Dynamic Web. 20th Workshop on Principles ofAdvanced and Distributed Simulation (PADS '06). IEEE Computer Society, Washington, DC, USA

[12] "Cloud Computing: Clash of the clouds" (http:/ / www. economist. com/ displaystory. cfm?story_id=14637206). The Economist.2009-10-15. . Retrieved 2009-11-03.

[13] "Gartner Says Cloud Computing Will Be As Influential As E-business" (http:/ / www. gartner. com/ it/ page. jsp?id=707508). Gartner. .Retrieved 2010-08-22.

[14] Gruman, Galen (2008-04-07). "What cloud computing really means" (http:/ / www. infoworld. com/ d/ cloud-computing/what-cloud-computing-really-means-031). InfoWorld. . Retrieved 2009-06-02.

[15] "Jeff Bezos' Risky Bet" (http:/ / www. businessweek. com/ magazine/ content/ 06_46/ b4009001. htm), Business Week,[16] "Amazon’s early efforts at cloud computing partly accidental" (http:/ / itknowledgeexchange. techtarget. com/ cloud-computing/ 2010/ 06/

17/ amazons-early-efforts-at-cloud-computing-partly-accidental/ ), IT Knowledge Exchange, Tech Target, 2010‐6‐17,[17] B Rochwerger, J Caceres, RS Montero, D Breitgand, E Elmroth, A Galis, E Levy, IM 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 ofResearch and Development, Vol. 53, No. 4. (2009)

[18] D Kyriazis, A Menychtas, G Kousiouris, K Oberle, T Voith, M Boniface, E Oliveros, T Cucinotta, S Berger, “A Real-time Service OrientedInfrastructure”, International Conference on Real-Time and Embedded Systems (RTES 2010), Singapore, November 2010

[19] Keep an eye on cloud computing (http:/ / www. networkworld. com/ newsletters/ itlead/ 2008/ 070708itlead1. html), Amy Schurr, NetworkWorld, 2008-07-08, citing the Gartner report, "Cloud Computing Confusion Leads to Opportunity". Retrieved 2009-09-11.

[20] Gartner Says Worldwide IT Spending On Pace to Surpass Trillion in 2008 (http:/ / www. gartner. com/ it/ page. jsp?id=742913), Gartner,2008-08-18. Retrieved 2009-09-11.

[21] "Launch of IBM Smarter Computing" (https:/ / www-304. ibm. com/ connections/ blogs/ IBMSmarterSystems/ date/ 201102?lang=en_us). .Retrieved 1 March 2011.

[22] "What's In A Name? Utility vs. Cloud vs Grid" (http:/ / www. datacenterknowledge. com/ archives/ 2008/ Mar/ 25/whats_in_a_name_utility_vs_cloud_vs_grid. html). Datacenterknowledge.com. . Retrieved 2010-08-22.

[23] "Distributed Application Architecture" (http:/ / java. sun. com/ developer/ Books/ jdbc/ ch07. pdf). Sun Microsystem. . Retrieved2009-06-16.

[24] "Sun CTO: Cloud computing is like the mainframe" (http:/ / itknowledgeexchange. techtarget. com/ mainframe-blog/sun-cto-cloud-computing-is-like-the-mainframe/ ). Itknowledgeexchange.techtarget.com. 2009-03-11. . Retrieved 2010-08-22.

Cloud computing 21

[25] "It's probable that you've misunderstood 'Cloud Computing' until now" (http:/ / portal. acm. org/ citation. cfm?id=1496091. 1496100&coll=& dl=ACM& CFID=21518680& CFTOKEN=18800807). TechPluto. . Retrieved 2010-09-14.

[26] Danielson, Krissi (2008-03-26). "Distinguishing Cloud Computing from Utility Computing" (http:/ / www. ebizq. net/ blogs/ saasweek/2008/ 03/ distinguishing_cloud_computing/ ). Ebizq.net. . Retrieved 2010-08-22.

[27] "Recession Is Good For Cloud Computing – Microsoft Agrees" (http:/ / www. cloudave. com/ link/recession-is-good-for-cloud-computing-microsoft-agrees). CloudAve. . Retrieved 2010-08-22.

[28] "Defining "Cloud Services" and "Cloud Computing"" (http:/ / blogs. idc. com/ ie/ ?p=190). IDC. 2008-09-23. . Retrieved 2010-08-22.[29] "e-FISCAL project state of the art repository" (http:/ / www. efiscal. eu/ state-of-the-art). .[30] Farber, Dan (2008-06-25). "The new geek chic: Data centers" (http:/ / news. cnet. com/ 8301-13953_3-9977049-80. html). CNET News. .

Retrieved 2010-08-22.[31] King, Rachael (2008-08-04). "Cloud Computing: Small Companies Take Flight" (http:/ / www. businessweek. com/ technology/ content/

aug2008/ tc2008083_619516. htm). Businessweek. . Retrieved 2010-08-22.[32] Mao, Ming; M. Humphrey (2012). "A Performance Study on the VM Startup Time in the Cloud" (http:/ / ieeexplore. ieee. org/ stamp/

stamp. jsp?tp=& arnumber=6253534& isnumber=6253471). Proceedings of 2012 IEEE 5th International Conference on Cloud Computing(Cloud2012). .

[33] "Defining and Measuring Cloud Elasticity" (http:/ / digbib. ubka. uni-karlsruhe. de/ volltexte/ 1000023476). KIT Software QualityDepartement. . Retrieved 13 August 2011.

[34] "Economies of Cloud Scale Infrastructure" (http:/ / www. youtube. com/ watch?v=nfDsY3f4nVI). Cloud Slam 2011. . Retrieved 13 May2011.

[35] "Encrypted Storage and Key Management for the cloud" (http:/ / www. cryptoclarity. com/ CryptoClarityLLC/ Welcome/ Entries/ 2009/ 7/23_Encrypted_Storage_and_Key_Management_for_the_cloud. html). Cryptoclarity.com. 2009-07-30. . Retrieved 2010-08-22.

[36] Mills, Elinor (2009-01-27). "Cloud computing security forecast: Clear skies" (http:/ / news. cnet. com/ 8301-1009_3-10150569-83. html).CNET News. . Retrieved 2010-08-22.

[37] David Perera (2012-07-12). "The real obstacle to federal cloud computing" (http:/ / www. fiercegovernmentit. com/ story/real-obstacle-federal-cloud-computing/ 2012-07-12). FierceGovernmentIT. . Retrieved 2012-12-15.

[38] "Top 10 Reasons why Startups should Consider Cloud" (http:/ / cloudstory. in/ 2012/ 07/top-10-reasons-why-startups-should-consider-cloud/ ). Cloudstory.in. 2012-09-05. . Retrieved 2012-12-15.

[39] "HP's Turn-Key Private Cloud - Application Development Trends" (http:/ / adtmag. com/ blogs/ watersworks/ 2010/ 08/hps-turn-key-private-cloud. aspx). Adtmag.com. 2010-08-30. . Retrieved 2012-12-15.

[40] Babcock, Charles (2011-06-03). "RightScale Launches App Store For Infrastructure - Cloud-computing" (http:/ / www. informationweek.com/ news/ cloud-computing/ infrastructure/ 229900165). Informationweek.com. . Retrieved 2012-12-15.

[41] "Red Hat launches hybrid cloud management software - Open Source" (http:/ / www. techworld. com. au/ article/ 426861/red_hat_launches_hybrid_cloud_management_software). Techworld. 2012-06-06. . Retrieved 2012-12-15.

[42] Brown, Rodney. "Spinning up the instant cloud," CloudEcosystem, April 10, 2012[www.cloudecosystem.com/author.asp?section_id=1873&doc_id=242031]

[43] Riglian, Adam., "VIP Art Fair picks OpDemand over RightScale for IaaS management," SearchCloudApplications.com, December 1, 2011(http:/ / searchcloudapplications. techtarget. com/ news/ 2240111861/ VIP-Art-Fair-picks-OpDemand-over-RightScale-for-IaaS-management)

[44] Samson, Ted (April 10, 2012). "HP advances public cloud as part of ambitious hybrid cloud strategy" (http:/ / www. infoworld. com/ t/hybrid-cloud/ hp-advances-public-cloud-part-of-ambitious-hybrid-cloud-strategy-190524). InfoWorld. . Retrieved 2012-12-14.

[45] "HP Cloud Maps can ease application automation," SiliconIndia, January 24, 2012 (http:/ / www. siliconindia. com/ shownews/HP_Cloud_Maps_can_Ease_Application_Automation-nid-103866-cid-7. html)

[46] Voorsluys, William; Broberg, James; Buyya, Rajkumar (February 2011). "Introduction to Cloud Computing" (http:/ / media. johnwiley.com. au/ product_data/ excerpt/ 90/ 04708879/ 0470887990-180. pdf). In R. Buyya, J. Broberg, A.Goscinski. Cloud Computing: Principlesand Paradigms. New York, USA: Wiley Press. pp. 1–44. ISBN 978-0-470-88799-8. .

[47] "ITU-T NEWSLOG - CLOUD COMPUTING AND STANDARDIZATION: TECHNICAL REPORTS PUBLISHED" (http:/ / www. itu.int/ ITU-T/ newslog/ Cloud+ Computing+ And+ Standardization+ Technical+ Reports+ Published. aspx). International TelecommunicationUnion (ITU). . Retrieved 16 December 2012.

[48] Amies, Alex; Sluiman, Harm; Tong, Qiang Guo; Liu, Guo Ning (July 2012). "Infrastructure as a Service Cloud Concepts" (http:/ / www.ibmpressbooks. com/ bookstore/ product. asp?isbn=9780133066845). Developing and Hosting Applications on the Cloud. IBM Press.ISBN 978-0-13-306684-5. .

[49] Hamdaqa, Mohammad. A Reference Model for Developing Cloud Applications (http:/ / www. stargroup. uwaterloo. ca/ ~mhamdaqa/publications/ A REFERENCEMODELFORDEVELOPINGCLOUD APPLICATIONS. pdf). .

[50] Chou, Timothy. Introduction to Cloud Computing: Business & Technology (http:/ / www. scribd. com/ doc/ 64699897/Introduction-to-Cloud-Computing-Business-and-Technology). .

[51] "HVD: the cloud's silver lining" (http:/ / www. intrinsictechnology. co. uk/ FileUploads/ HVD_Whitepaper. pdf). Intrinsic Technology. .Retrieved 30 August 2012.

[52] "ITU Focus Group on Cloud Computing - Part 1" (http:/ / www. itu. int/ en/ ITU-T/ focusgroups/ cloud/ Documents/FG-coud-technical-report. zip). International Telecommunication Union (ITU) TELECOMMUNICATION STANDARDIZATION SECTOROF ITU. . Retrieved 16 December 2012.

Cloud computing 22

[53] "Cloud computing in Telecommunications" (http:/ / www. ericsson. com/ res/ thecompany/ docs/ publications/ ericsson_review/ 2010/cloudcomputing. pdf). Ericsson. . Retrieved 16 December 2012.

[54] "Network Virtualisation – Opportunities and Challenges" (http:/ / archive. eurescom. eu/ ~pub/ deliverables/ documents/ P1900-series/P1956/ D1/ P1956-D1. pdf). Eurescom. . Retrieved 16 December 2012.

[55] "The role of virtualisation in future network architectures" (http:/ / www. change-project. eu/ fileadmin/ publications/ Presentations/CHANGE_-_The_role_of_virtualisation_in_future_network_infrastructures_-_Warsaw_cluster_workshop_contribution. pdf). Change Project.. Retrieved 16 December 2012.

[56] Stevens, Alan (June 29, 2011). "When hybrid clouds are a mixed blessing" (http:/ / www. theregister. co. uk/ 2011/ 06/ 29/ hybrid_cloud/ ).The Register (http:/ / www. theregister. co. uk). . Retrieved March 28, 2012.

[57] "Is a Private Cloud Really More Secure?" (http:/ / www. dell. com/ Learn/ us/ en/ rc956904/ large-business/ private-cloud-more-secure).Dell.com. . Retrieved 07-11-12.

[58] Foley, John. "Private Clouds Take Shape" (http:/ / www. informationweek. com/ news/ services/ business/ showArticle.jhtml?articleID=209904474). InformationWeek. . Retrieved 2010-08-22.

[59] Haff, Gordon (2009-01-27). "Just don't call them private clouds" (http:/ / news. cnet. com/ 8301-13556_3-10150841-61. html). CNET News.. Retrieved 2010-08-22.

[60] "There's No Such Thing As A Private Cloud" (http:/ / www. informationweek. com/ cloud-computing/theres-no-such-thing-as-a-private-cloud/ 229207922). InformationWeek. 2010-06-30. . Retrieved 2010-08-22.

[61] "Building GrepTheWeb in the Cloud, Part 1: Cloud Architectures" (http:/ / developer. amazonwebservices. com/ connect/ entry.jspa?externalID=1632& categoryID=100). Developer.amazonwebservices.com. . Retrieved 2010-08-22.

[62] Bernstein, David; Ludvigson, Erik; Sankar, Krishna; Diamond, Steve; Morrow, Monique (2009-05-24). Blueprint for the Intercloud –Protocols and Formats for Cloud Computing Interoperability (http:/ / www2. computer. org/ portal/ web/ csdl/ doi/ 10. 1109/ ICIW. 2009.55). IEEE Computer Society. pp. 328–336. doi:10.1109/ICIW.2009.55. .

[63] "Kevin Kelly: A Cloudbook for the Cloud" (http:/ / www. kk. org/ thetechnium/ archives/ 2007/ 11/ a_cloudbook_for. php). Kk.org. .Retrieved 2010-08-22.

[64] "Intercloud is a global cloud of clouds" (http:/ / samj. net/ 2009/ 06/ intercloud-is-global-cloud-of-clouds. html). Samj.net. 2009-06-22. .Retrieved 2010-08-22.

[65] "Vint Cerf: Despite Its Age, The Internet is Still Filled with Problems" (http:/ / www. readwriteweb. com/ archives/vint_cerf_despite_its_age_the. php?mtcCampaign=2765). Readwriteweb.com. . Retrieved 2010-08-22.

[66] "SP360: Service Provider: From India to Intercloud" (http:/ / blogs. cisco. com/ sp/ comments/ from_india_to_intercloud/ ).Blogs.cisco.com. . Retrieved 2010-08-22.

[67] Canada (2007-11-29). "Head in the clouds? Welcome to the future" (http:/ / www. theglobeandmail. com/ servlet/ story/ LAC. 20071129.TWLINKS29/ TPStory/ Business). Toronto: Theglobeandmail.com. . Retrieved 2010-08-22.

[68] Cauley, Leslie (2006-05-11). "NSA has massive database of Americans' phone calls" (http:/ / www. usatoday. com/ news/ washington/2006-05-10-nsa_x. htm). USATODAY.com. . Retrieved 2010-08-22.

[69] Winkler, Vic (2011). Securing the Cloud: Cloud Computer Security Techniques and Tactics (http:/ / www. elsevier. com/ wps/ find/bookdescription. cws_home/ 723529/ description). Waltham, Massachusetts: Elsevier. p. 60. ISBN 978-1-59749-592-9. .

[70] "Feature Guide: Amazon EC2 Availability Zones" (http:/ / developer. amazonwebservices. com/ connect/ entry. jspa?externalID=1347&categoryID=112). Amazon Web Services. . Retrieved 2010-08-22.

[71] "Cloud Computing Privacy Concerns on Our Doorstep" (http:/ / cacm. acm. org/ magazines/ 2011/ 1/103200-cloud-computing-privacy-concerns-on-our-doorstep/ fulltext). .

[72] "Cloud Enables New Business Opportunity" (http:/ / smartenterpriseexchange. com/ community/ execution/ blog/ 2011/ 06/ 13/cloud-enables-new-business-opportunity/ fulltext). .

[73] "FISMA compliance for federal cloud computing on the horizon in 2010" (http:/ / searchcompliance. techtarget. com/ news/ article/0,289142,sid195_gci1377298,00. html). SearchCompliance.com. . Retrieved 2010-08-22.

[74] "Google Apps and Government" (http:/ / googleenterprise. blogspot. com/ 2009/ 09/ google-apps-and-government. html). Official GoogleEnterprise Blog. 2009-09-15. . Retrieved 2010-08-22.

[75] "Cloud Hosting is Secure for Take-off: Mosso Enables The Spreadsheet Store, an Online Merchant, to become PCI Compliant" (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/ ). Rackspace.2009-03-14. . Retrieved 2010-08-22.

[76] "Amazon gets SAS 70 Type II audit stamp, but analysts not satisfied" (http:/ / searchcloudcomputing. techtarget. com/ news/ article/0,289142,sid201_gci1374629,00. html). SearchCloudComputing.com. 2009-11-17. . Retrieved 2010-08-22.

[77] "Assessing Cloud Computing Agreements and Controls" (http:/ / wistechnology. com/ articles/ 6954/ ). WTN News. . Retrieved 2010-08-22.[78] "Cloud Certification From Compliance Mandate to Competitive Differentiator" (http:/ / www. youtube. com/ watch?v=wYiFdnZAlNQ).

Cloudcor. . Retrieved 2011-09-20.[79] "How the New EU Rules on Data Export Affect Companies in and Outside the EU | Dr. Thomas Helbing – Kanzlei für Datenschutz-,

Online- und IT-Recht" (http:/ / www. thomashelbing. com/ en/ how-new-eu-rules-data-export-affect-companies-and-outside-eu). Dr. ThomasHelbing. . Retrieved 2010-08-22.

[80] "FedRAMP" (http:/ / www. gsa. gov/ portal/ category/ 102371). U.S. General Services Administration. 2012-06-13. . Retrieved 2012-06-17.

Cloud computing 23

[81] Cohn, Cindy; Samuels, Julie (31 October 2012). "Megaupload and the Government's Attack on Cloud Computing (https:/ / www. eff. org/deeplinks/ 2012/ 10/ governments-attack-cloud-computing)"]. Electronic Frontier Foundation. . Retrieved 2012-12-14.

[82] Maltais, Michelle (26 April 2012). "Who owns your stuff in the cloud?" (http:/ / articles. latimes. com/ 2012/ apr/ 26/ business/la-fi-tech-savvy-cloud-services-20120426). Los Angeles Times. . Retrieved 2012-12-14.

[83] Jon Brodkin (July 28, 2008). "Open source fuels growth of cloud computing, software-as-a-service" (http:/ / www. networkworld. com/news/ 2008/ 072808-open-source-cloud-computing. html). Network World. . Retrieved 2012-12-14.

[84] "VMware Launches Open Source PaaS Cloud Foundry" (http:/ / www. cmswire. com/ cms/ information-management/vmware-launches-open-source-paas-cloud-foundry-010941. php). Simpler Media Group, Inc.. 2011-04-21. . Retrieved 2012-12-14.

[85] "AGPL: Open Source Licensing in a Networked Age" (http:/ / redmonk. com/ sogrady/ 2009/ 04/ 15/open-source-licensing-in-a-networked-age/ ). Redmonk.com. 2009-04-15. . Retrieved 2010-08-22.

[86] GoGrid Moves API Specification to Creative Commons (http:/ / www. gogrid. com/ company/ press-releases/gogrid-moves-api-specification-to-creativecommons. php)

[87] "Eucalyptus Completes Amazon Web Services Specs with Latest Release" (http:/ / ostatic. com/ blog/eucalyptus-completes-amazon-web-services-specs-with-latest-release). Ostatic.com. . Retrieved 2010-08-22.

[88] "OpenStack Foundation launches" (http:/ / www. infoworld. com/ d/ cloud-computing/ openstack-foundation-launches-202694/ ).Infoworld.com. 2012-09-19. . Retrieved 2012-17-11.

[89] "Did OpenStack Let VMware Into The Henhouse?" (http:/ / www. informationweek. com/ development/ open-source/did-openstack-let-vmware-into-the-henhou/ 240009337). Informationweek.com. 2012-10-19. . Retrieved 2012-17-11.

[90] Zissis, Dimitrios; Lekkas (2010). "Addressing cloud computing security issues" (http:/ / www. sciencedirect. com/ science/ article/ pii/S0167739X10002554). Future Generation Computer Systems. doi:10.1016/j.future.2010.12.006. .

[91] Winkler, Vic (2011). Securing the Cloud: Cloud Computer Security Techniques and Tactics (http:/ / www. elsevier. com/ wps/ find/bookdescription. cws_home/ 723529/ description#description). Waltham, MA USA: Syngress. pp. 187, 189. ISBN 978-1-59749-592-9. .

[92] "Are security issues delaying adoption of cloud computing?" (http:/ / www. networkworld. com/ news/ 2009/042709-burning-security-cloud-computing. html). Network World. . Retrieved 2010-08-22.

[93] "Security of virtualization, cloud computing divides IT and security pros" (http:/ / www. networkworld. com/ news/ 2010/022210-virtualization-cloud-security-debate. html). Network World. 2010-02-22. . Retrieved 2010-08-22.

[94] Armbrust, M; Fox, A., Griffith, R., Joseph, A., Katz, R., Konwinski, A., Lee, G., Patterson, D., Rabkin, A., Zaharia, (2010). "A view ofcloud computing.". Communication of the ACM 53 (4): 50–58. doi:10.1145/1721654.1721672.

[95] Anthens, G. "Security in the cloud". Communications of the ACM 53 (11). doi:10.1145/1839676.1839683.[96] James Urquhart (January 7, 2010). "Cloud computing's green paradox" (http:/ / news. cnet. com/ 8301-19413_3-10428065-240. html).

CNET News. . Retrieved March 12, 2010. "...there is some significant evidence that the cloud is encouraging more compute consumption"[97] Finland – First Choice for Siting Your Cloud Computing Data Center. (http:/ / www. fincloud. freehostingcloud. com/ ). Retrieved 4 August

2010.[98] Swiss Carbon-Neutral Servers Hit the Cloud. (http:/ / www. greenbiz. com/ news/ 2010/ 06/ 30/ swiss-carbon-neutral-servers-hit-cloud).

Retrieved 4 August 2010.[99] Berl, Andreas, et al., Energy-Efficient Cloud Computing (http:/ / comjnl. oxfordjournals. org/ content/ 53/ 7/ 1045. short), The Computer

Journal, 2010.[100] Farrahi Moghaddam, Fereydoun, et al., Low Carbon Virtual Private Clouds (http:/ / ieeexplore. ieee. org/ search/ srchabstract. jsp?tp=&

arnumber=6008718), IEEE Cloud 2011.[101] Alpeyev, Pavel (2011-05-14). "Amazon.com Server Said to Have Been Used in Sony Attack" (http:/ / www. bloomberg. com/ news/

2011-05-13/ sony-network-said-to-have-been-invaded-by-hackers-using-amazon-com-server. html). Bloomberg. . Retrieved 2011-08-20.[102] Goodin, Dan (2011-05-14). "PlayStation Network hack launched from Amazon EC2" (http:/ / www. theregister. co. uk/ 2011/ 05/ 14/

playstation_network_attack_from_amazon/ ). The Register. . Retrieved 2012-05-18.[103] Hsu, Wen-Hsi L., “Conceptual Framework of Cloud Computing Governance Model - An Education Perspective”, IEEE Technology and

Engineering Education (ITEE), Vol 7, No 2 (2012) (http:/ / www. ewh. ieee. org/ soc/ e/ sac/ itee/ index. php/ meem/ article/ view/ 240)[104] Stackpole, Beth, “Governance Meets Cloud: Top Misconceptions”, InformationWeek, 7 May 2012 (http:/ / www. informationweek. com/

cloud-computing/ infrastructure/ governance-meets-cloud-top-misconception/ 232901483)[105] Joha, A and M. Janssen (2012) “Transformation to Cloud Services Sourcing: Required IT Governance Capabilities”, ICST Transactions on

e-Business 12(7-9) (http:/ / eudl. eu/ pdf/ 10. 4108/ eb. 2012. 07-09. e4)[106] "Cloud Net Directory. Retrieved 2010-03-01" (http:/ / www. cloudbook. net/ directories/ research-clouds). Cloudbook.net. . Retrieved

2010-08-22.[107] "– National Science Foundation (NSF) News – National Science Foundation Awards Millions to Fourteen Universities for Cloud

Computing Research – US National Science Foun" (http:/ / www. nsf. gov/ news/ news_summ. jsp?cntn_id=114686). Nsf.gov. . Retrieved2011-08-20.

[108] Rich Miller (2008-05-02). "IBM, Google Team on an Enterprise Cloud" (http:/ / www. datacenterknowledge. com/ archives/ 2008/ 05/ 02/ibm-google-team-on-an-enterprise-cloud/ ). DataCenterKnowledge.com. . Retrieved 2010-08-22.

[109] "StACC - Collaborative Research in Cloud Computing" (http:/ / www. cs. st-andrews. ac. uk/ stacc). University of St Andrews departmentof Computer Science. . Retrieved 2012-06-17.

Cloud computing 24

[110] "Trustworthy Clouds: Privacy and Resilience for Internet-scale Critical Infrastructure" (http:/ / www. tclouds-project. eu). . Retrieved2012-06-17.

[111] Ko, Ryan K. L.; Jagadpramana, Peter; Lee, Bu Sung (2011). "Flogger: A File-centric Logger for Monitoring File Access and Transferswithin Cloud Computing Environments" (http:/ / www. hpl. hp. com/ techreports/ 2011/ HPL-2011-119. pdf). Proceedings of the 10th IEEEInternational Conference on Trust, Security and Privacy of Computing and Communications (TrustCom-11). .

[112] Ko, Ryan K. L.; Jagadpramana, Peter; Mowbray, Miranda; Pearson, Siani; Kirchberg, Markus; Liang, Qianhui; Lee, Bu Sung (2011)."TrustCloud: A Framework for Accountability and Trust in Cloud Computing" (http:/ / www. hpl. hp. com/ techreports/ 2011/ HPL-2011-38.pdf). Proceedings of the 2nd IEEE Cloud Forum for Practitioners (IEEE ICFP 2011), Washington DC, USA, July 7–8, 2011. .

[113] Ko, Ryan K. L. Ko; Kirchberg, Markus; Lee, Bu Sung (2011). "From System-Centric Logging to Data-Centric Logging - Accountability,Trust and Security in Cloud Computing" (http:/ / www. hpl. hp. com/ people/ ryan_ko/ RKo-DSR2011-Data_Centric_Logging. pdf).Proceedings of the 1st Defence, Science and Research Conference 2011 - Symposium on Cyber Terrorism, IEEE Computer Society, 3–4August 2011, Singapore. .

[114] "Publication Download" (http:/ / www. tiaonline. org/ market_intelligence/ publication_download.cfm?file=TIA_Cloud_Computing_White_Paper). Tiaonline.org. . Retrieved 2011-12-02.

External links• The True Cost of Cloud Computing by Donn Gurule (http:/ / lightbeamsystems. com/ lightbeam-blog/

80-the-true-cost-of-cloud-computing. html)• The NIST Definition of Cloud Computing (http:/ / csrc. nist. gov/ publications/ nistpubs/ 800-145/ SP800-145.

pdf). Peter Mell and Timothy Grance, NIST Special Publication 800-145 (September 2011). National Institute ofStandards and Technology, U.S. Department of Commerce.

• Guidelines on Security and Privacy in Public Cloud Computing (http:/ / nvlpubs. nist. gov/ nistpubs/ sp/ 2011/sp800-144. pdf). Wayne Jansen and Timothy Grance, NIST Special Publication 800-144 (December 2011).National Institute of Standards and Technology, U.S. Department of Commerce.

• Cloud Computing - Benefits, risks and recommendation for information security (http:/ / www. enisa. europa. eu/activities/ risk-management/ files/ deliverables/ cloud-computing-risk-assessment). Daniele Cattedu and GilesHobben, European Network and Information Security Agency 2009.

• Fighting cyber crime and protecting privacy in the cloud. European Parliament - Directorate-General for InternalPolicies. 2012 (http:/ / www. europarl. europa. eu/ committees/ en/ studiesdownload.html?languageDocument=EN& file=79050)

Article Sources and Contributors 25

Article Sources and ContributorsGrid computing  Source: http://en.wikipedia.org/w/index.php?oldid=532419283  Contributors: *drew, 28bytes, 74s181, ABF, Aaahni, Aeris-chan, Aforgue, Agentofstrange, Agoiste,Airplaneman, Aitter, Ajm661023, Akel Desyn, Akriasas, Alansohn, Alexf, Alexius08, Alll, Alvestrand, Amin123, Amwebb, Andrea.rodolico, Andremerzky, Andreww, Angwill, Arad7613,Aramallo, Armando, Art Carlson, Ash.banerjee@gmail.com, Attila.redegliunni, Aulis Eskola, Bact, BaldPark, Bamyers99, Barmijo, Bask, Beetstra, Beland, Benjaminhill, Bento00, Bethenco,Billmania, Blacktensor, Bobo192, Bongwarrior, Bovineone, Brenont, Brighterorange, Bsadowski1, BullRangifer, Buyya, C.A.T.S. CEO, C.Fred, CBurne, Catgut, CeciliaPang, Celique,Ceta-ciemat, Charles Gaudette, CharlotteWebb, Chentz, ChrisGualtieri, Christopher Mahan, Chriswood123, Cincaipatrin, Ciphers, Ckatz, Cmdrjameson, Coelacan, Comcrazy, Cookie1088, CplSyx, Cranraspberry, Crumbsteve, Cyrius, DanielWaterworth, Danleech, Davemck, David McBride, David.Horat, Davidnerdman, Dcallen, Dcresti, Dder, Depressperado, Dgies, Didier So,Dil·et·tante, Discospinster, Dkf11, Dmtfw, Dogbreath, DopefishJustin, Douglas.mckinley, Dreadstar, Dsetrakyan, DueSouth, Durin, E Wing, Eddy.caron, Edward, Ehheh, Ehuedo, Equendil,Ericrosbh, Euyyn, Everyking, Expertjohn, Fabio.kon, Faizanalivarya, FayssalF, Foss.AK, Francesco-lelli, Frehley, GF, Georgewilliamherbert, GorillaWarfare, GrahamPeterson, GridMeUp,Gridstock, HRV, Hammersoft, Heimstern, HeinzStockinger, Hemantclimate, Henry W. Schmitt, Herbee, Heron, Higdont, History2007, I already forgot, I philpot, Idleguy, Ilanrab, InsanityIncarnate, Intershark, Iridescent, Isilanes, Ismail4340, IvanLanin, J Di, J.delanoy, JCLately, JForget, JNW, JTN, Jackoster, Jainyours, Jan Hidders, Jaybna, Jdm64, Jfmantis, Jgwacker, JoachimSchrod, Joeth, John Gerent, John of Reading, JohnCD, JonHarder, Josemariasaldana, Joy, Julian Mendez, Kaihsu, Kfor, Kimsey0, Kinett, Kingpin13, Kinhull, Kku, Kocio, Kozuch,Krzysztof.kurowski, Kubanczyk, Kuru, LA2, LX, LakeHMM, Lancevortex, Lasai, Laszewsk, LeAd DiAg, Lightmouse, LilHelpa, LinuxDude, Lolipop23, LorenzoRims, Lyondif02, MER-C,Magnusvk, Malcohol, Margin1522, Mark Arsten, Matttoothman, Max-CCC, Mboverload, Michig, Mika au, Missy Prissy, Miym, Mjboniface, Mmernex, Mmgicuk, Mo ainm, MrOllie, Mrwojo,Msavidge, Mukadderat, Mvanwaveren, Mwtoews, N8Dawg, Nakon, Nbgr, Ne vasya, NellieBly, Nivanov, Nurg, Nzwaneveld, Octahedron80, Ohnoitsjamie, Onlineramya, Ora, Ostersc, Otvaltak,Ovaiskhan, Oxana.smirnova, Paladin1979, Pankaj saha, Panleek, Pansanel, PdDemeter, Pdalcourt, Pedant17, Pest74, Peter Hitchmough, Phaedrus86, PhilKnight, Philip Trueman,Philomathoholic, Phr, Piano non troppo, PizzaMargherita, Poppy, Powerload, Prefect42, Psplendid, Pyabo, Quux, Qwertyus, Qxz, Ramu50, RandomAct, Ratiocinate, Raul654, Raysonho,Requestion, Rich Farmbrough, Richard Robert, Rjanag, Rjwilmsi, Rklawton, Robertp24, Robth, Roczei, Rogerd, Ronen.hamias, Ronz, Rotem Dan, Rw2, SF007, Salexandre, Sam Hocevar,SamJohnston, SamJohnston (usurped), Samuel Blanning, Sbrickey, Scholar2007, SciHalo, Secured128, Setu, Shadowjams, Shajulin, Shaze, Shigdon, Shinypup, Sietse Snel, Sir Lewk, SirDuncan,Sjakkalle, Sjanusz, Slartoff, Smoe, Smsarmad, Smyth, Snapper five, Soumyasch, Spardi, Spliffy, Sridev, Srikrishnan, Srknaustin, Stephan Leeds, Stephen Balaban, Stjones86, Strainu, Strait,Syrthiss, Tabletop, Tarquin, Tassedethe, Tcaruso2, Teambarrett, Technologyvoices, Tenusplayor, The Anome, The Thing That Should Not Be, Thebestofall007, Thecheesykid, Thingg, Tide rolls,Tobble, Tommy2010, Traviscj, Triadic2000, Troubadorian, VictorAnyakin, Vikramandem, Volphy, W Nowicki, Wayne Schroeder, Wdustbuster, Webhpc, Welsh, Whiteandnerdy52, Wikiant,Wmahan, Xaosflux, Ybgir, Yelkhatib, Yesyayen, Yknott, Your Lord and Master, Yvesnimmo, Zach Garner, Zagen30, Δ, 815 anonymous edits

Cloud computing  Source: http://en.wikipedia.org/w/index.php?oldid=532396188  Contributors: 1337H4XX0R, 1exec1, 2001:4C28:194:520:1A03:73FF:FE0A:7269, 21hattongardens, 28bytes, 623des, 842U, 9Engine, A. B., A.K.Karthikeyan, A.Ward, A520, A8UDI, A930913, Aaditya025, Aavindraa, Abb615, AbdullahHaydar, Abligh, Abrahami, Aburreson, Acaliguiran, Acandus, Acather96, Achimew, Achowat, Acrooney, AcuteSys, Adam Hauner, Aditya.smn, AdityaTandon, Adjectivore, Adlawlor, Aflagg99, Agemoi, Ahunt, Ajraddatz, Akropp, Alankc, Alanmonteith, Alansohn, Alex5678, Alexamies, Alexlange, Allenmwnc, Allens, Aloak1, Amartya71, Ameliorate!, American Eagle, Amitgupta2792, Amoebat, Amore proprio, AnOddName, Anamika.search, Anandcv, Anderson, Andersoniooi, Andromani, Andy Dingley, Andyg511, Aneesh1981, Angrywikiuser, Anikingos, Anna Frodesiak, Anne.naimoli, Anonymous Dissident, Ansumang, AoV2, ArglebargleIV, Arnavrox, Ashakeri3596, Ashley Pomeroy, Ashley thomas80, Ashleymcneff, Asieo, AstralWiki, Auntof6, Aurifier, Avacam, Avermapub, Avillaba, Avlnet, Avneralgom, Avoided, Axorc, B Fizz, BD2412, BDavis27, Balaarjunan, BaldPark, Balvord, Bamtelim, Barmijo, Beanilkumar, Beer2beer, Beetstra, Bejnar, Belfry, Beltman R., Bencey, Bentogoa, Bernd in Japan, Berny68, Betswiki, Bidgee, Bigfella1123, Biglovinb, Bijoysr, Bikeborg, Bill.albing, Biscuittin, Bkengland, Blaxthos, Blvrao, Bob bobato, Bob.gourley@comcast.net, BobGourley, Bodhran, Bonadea, Bongwarrior, BostonRed, Bovineone, Bped1985, Bpgriner, BrennaElise, BrianWren, Brianwc, Bruce404, Bshende, Bubba73, Bulldog73, Bumm13, Burrows01, Bus stop, Businesstecho, ByM4k5, C. A. Russell, CKlunck, CPieras, Cajetan da kid, Calabe1992, CanadianLinuxUser, Candace Gillhoolley, Capricorn42, Carl presscott, Casieg, Casliber, CastAStone, Cbdorsett, Cemgurkok, Certitude1, Chadastrophic, Chaheel Riens, Chanakal, ChangChienFu, Chapmagr, Chiefspartan, Chintan4u, Chishtigharana, Chmyr, Chris the speller, Chris55, Christian75, Chriswriting, Chuahcsy, CitizenB, Ckatz, ClamDip, CliffC, CloudComputing, Cloudcoder, Cloudcto, Cloudfest, Cloudnitc, Cloudreviewer, Cloudxtech, Clovis Sangrail, Clutterpad, Cmartell, Colleenhaskett, Colonies Chris, ConcernedVancouverite, Cornelius383, Courcelles, Cpl Syx, Crackerspeanut12, Craig.Coward, Cronos4d, Crysb, Csabo, Cst17, Curtbeckmann, Cybercool10, Czarkoff, D rousslan, DARTH SIDIOUS 2, DBigXray, DJ Clayworth, DSP-user, DVdm, Dadomusic, Dan6hell66, DanStern, Dancter, Danielchalef, Danielrs, Dannymjohnson, Darktemplar, Darkyeffectt, DarrenOP, DaudSharif, Davewild, David H Braun (1964), DavidLam, Davidogm, Dbake, Dbrisinda, Declan Clam, Deepalja, Deicool, Deineka, DeleoB, DellTechWebGuy, Denisarona, Derekvicente, Dethomas, Devinek22, DexDor, Dfxdeimos, Diego Moya, Digestor81, Dimos2k, Dinferno, Dinhthaihoang, Dlohcierekim, Dlohcierekim's sock, Dlowenberger, Dlrohrer2003, Dmcelroy1, Dmichaud, Doctorfree, Dogbertwp, Dogsbody, Dominik92, DoriSmith, Dougher, Dpsd 02011, Dr.K., DrFurey, DragonflyReloaded, Drjoseph7, Drphilharmonic, Dschrader, Dsp13, DuineSidhe, Dyepoy05, E Wing, E0steven, EDC5370, EEldridge1, ESkog, EagerToddler39, Earthlyreason, Ebhakt, Eco30, Edchi, Eddiev11, Edeskonline, Editorfry, Eeekster, Ego White Tray, Ehheh, Einasmadi, ElKevbo, Elassint, Elasticprovisioner, Elauminri, Elbarcino, Eleven even, EliyahuStern, Elminster Aumar, EmilyEgnyte, Emrekenci, Enc1234, Eniagrom, Epbr123, Er.madnet, Eric, EricEnfermero, EricTheRed20, Estahl, Esthon, Ethicalhackerin2010, Ethoslight, Eusbls, Evagarfer, Everything counts, Evil saltine, EwokiWiki, Explorer09, Fabrice Florin (WMF), Falcon8765, FallingGravity, FatalError, Favonian, FayssalF, Fb2ts, Fcalculators, Feinoha, Felipebm, Felixchu, Fergus Cloughley, Fieldday-sunday, Figaronline, Figureskatingfan, Finngall, Firsfron, Fishtron, Five-toed-sloth, ForthOK, Francis.w.usher, Frap, Frdfm, Freddymay, Frozen Wind, FunkyMonk101, Fvw, Fylbecatulous, Fzk chc, Fæ, GRevolution824, GVnayR, Gamber34, Gandalf44, Garima.rai30, Gary King, Gawali.jitesh, GcSwRhIc, Ggafraser, GhostModern, Giftlite, Gigs, Ginsengbomb, Gkorland, Glane23, Glass Sword, Gmm24, GorillaWarfare, Gotocloud, Gozzilli, Grafen, Gram123, Gratridge, Greensburger, GregorB, Grim Littlez, Guillaume2303, Guliolopez, Gxela, HJ Mitchell, Haakon, Hallows AG, HamburgerRadio, HandThatFeeds, HangingCurve, Happyinmaine, Hardduck, Haroldpolo, Harryboyles, Haseo9999, Hatfields, Helotrydotorg, Hemapi, HenryLarsen, Heracles31, Heroeswithmetaphors, Heron, Heyitscory, Hfoxwell, History2007, Hogne, Hu12, Hughesjp, Hutch8700, Huygens 25, Hydrox, IANYL, IDrivebackup, IHSscj, IXavier, Iamdavinci, Iamthenewno2, Ianlovesgolf, Ianmolynz, Identity20, Imeson, Iminvinciblekris, Imllorente, Imnotminkus, Imnz730, Imtiyaz 81, Imtiyazali4all, Indigokk, Info20072009, IronGargoyle, Ispabierto, Iste Praetor, Itangalo, Itzkishor, IvanLanin, J.delanoy, J04n, J36miles, JDC321, JForget, JLRedperson, JLaTondre, JMJeditor, JaGa, Jack Bauer00, Jack Greenmaven, Jack007, Jackoboss, Jacob Poon, Jacob1044, Jakeburns99, Jakemoilanen, Jamalystic, JamesBWatson, JamesLWilliams2010, JanaGanesan, Jandalhandler, Janniscui, Jarble, Jarrad Lewis, Jasapir, Javaeu, Jay-Sebastos, Jayvd, Jbadger88, Jbekuykendall, Jbucket, Jburns2009, Jdlh, Jean.julius, Jef4444, Jeff G., Jeh, Jerichochang97, Jerome Charles Potts, Jerryobject, Jesse.gibbs.elastra, Jhodge88, Jht4060, Jim1138, JimDelRossi, Jimmi Hugh, Jimsimwiki, Jineshvaria, Jinlye, Jkelleyy, Jlamus, Jldupont, Jleedev, Jmc, Jmillerfamily, Joe1689, JoeBulsak, Johananl, John-readyspace, John254, JohnCD, JohnJamesWIlson, JohnnyJohnny, Johnpltsui, Johnuniq, Jojalozzo, Jon.ssss, Jonathan.robie, JonathonReinhart, Jorunn, Jose Icaza, JoshDuffMan, JoshuaZ, Jpgordon, Jtschoonhoven, Julesd, Juliano, Juliashapiro, Jusdafax, Justinc, Jwt1801, JzG, Kawana, Keilana, Kenny Strawn, Kessler, Keynoteworld, Kgfleischmann, Khan.sharique1994, Kibbled bits, Kieransimkin, Kimdino, Kjohnthomas, Kkh03, Klilidiplomus, Kmsmgill, Knodir, Knoxi171, Kompere, KotetsuKat, Kozuch, Kpalsson, Krenair, Kridjsss, Kristiewells, Kronostar, Kubanczyk, Kunitakako, Kuru, Kvng, Kyerussell, L Kensington, L200817s, Lainagier, Lairdp, Lamro, LandoSr, LarryEFast, Larrymcp, Laser813, Latha as, Latticelattuce, Lavanyalava, Lbecque, Learn2009, Lee.kinser, Leifnsn, Leinsterboy, LemonairePaides, Lena322, Lerichard, Letdorf, Li Yue Depaul, Linuxbabu, Lionheartf, Lipun4u, LittleBenW, Littlewild, Liujiang, Liyf, LizardJr8, Lmbhull, Lmp90, Loadbang, Logan, Lone boatman, Lord Roem, Lorddunvegan, Lordfaust, Lotje, LuchoX, Luckas Blade, Luigi Baldassari, Luk, Lysy, M.O.X, MJ94, MPSTOR, Maasmiley, Mabdul, Macecanuck, Machilde, Macholl, Mahjongg, MainFrame, Makru, Malke 2010, Malleus Fatuorum, Manasprakash79, Mandarax, Mangai Vellingiri, Manishekhawat, Manishrai tester, Manop, Manusnake, Mariolina, Mark Arsten, Mark Renier, MarkCPhinn, Markoo3, Markqu, Markus95, Marokwitz, MarshallWilensky, Martin.ashcroft, Martinwguy, Materialscientist, Mathematrucker, Mathglot, Mathonius, Mattg82, Maurice Carbonaro, MaxedoutnjNJITWILL, Mayur, Mbblake, Mckaysalisbury, Mdd, Mean as custard, Meitar, Metapsyche, Metatinara, Mheikkurinen, Mhodapp, Michael Hardy, Michaelmas1957, MichealH, Miguelcaldas, Mike Rosoft, Mild Bill Hiccup, MillinKilli, Millycylan, Mindmatrix, Miracle Pen, Miym, Mkdonqui, Mlavannis, Mmanie, Mobilecloud, Moe Epsilon, Mohamed Magdy, Momoricks, Monkey Bounce, Monkeyfunforidiots, Moonriddengirl, Mortense, Moswento, Motyka, Mpcirba, Mr little irish, MrKG, MrMarmite, MrOllie, Mrt3366, Msfitzgibbonsaz, Msileinad, Muhandes, Mwarren us, Mwmaxey, Mychalmccabe, NaBUru38, Nabeez, Nadeemamin, Nakakapagpabagabag, Nasnema, Nasonmedia, Nasserjune, Natishalom, NatterJames, Naturelover007, Navywings, NawlinWiki, Nbarth, NeD80, Neko-chan, Nelliejellynoonaa, Nesjo, Neustradamus, NewEnglandYankee, Nfr-Maat, Nick Number, Nightscream, Nikoschance, Nimbus prof, Niri.M, Nithdaleman, Njcaus, Njkool, Nnemo, No1can, NocturneNoir, Nogburt, NonNobisSolum, Nookncranny, Nopetro, North wiki, Northamerica1000, Now3d, Nurnware, Ny156uk, Nyllo, OSRules, OSborn, Obdurodon, Ohnoitsjamie, Ohspite, Oleg Alexandrov, Olegwiki, OllieFury, Oluropo, Om23, OmbudsTech, Onmytoes4eva, Optatus, Orange Suede Sofa, Os connect, OsamaBinLogin, OsamaK, Oskilian, Otto ter Haar, Ourhistory153, PCHS-NJROTC, PJH4-NJITWILL, PMstdnt, Padmaja cool, Paj mccarthy, Palapa, Panoramak, Parveson, Patrickwooldridge, PaulQSalisbury, Paulmmn, PavelSolin, PcCoffee, Pea.hamilton, Pegordon, Person1988, Pete maloney, Peter Flass, Peterduffell, Pgan002, Pgj1997, Phazoni, Phil.gagner, PhilJackson, Philg88, Philopappos86, Piandcompany, Pinethicket, Piperh, Pisapatis, Pleft, Pmell, Pmj, Pmorinreliablenh, Pointillist, Poliverach, Pontificalibus, Popnose, Porqin, Pottersson, Ppachwadkar, Priyo123, Pumpmeup, Qarakesek, Qoncept, Quaeler, Quantling, Quebec99, QuentinUK, Qusayfadhel, R39132, RHaworth, RLSnow, RS-HKG, Rakesh india, Ramnathkc, Ramu50, Randhirreddy, Rangoon11, Ras67, Raushan Shahi, RayAYang, Razorflame, Ready, RealWorldExperience, Realtimer, Reaper Eternal, Rebuker, Recognizance, Reconsider the static, Reservoirhill, Reshadipoor, RetiredWikipedian789, Rich Farmbrough, Rich Janis, Richard Harvey, Richard.McGuire88, Richramos, Rickyphyllis, Rjwilmsi, Rms77, Rnb, Robert.Harker, Robert.ohaver, Robofish, Robscheele, Rolf-Peter Wille, Ronen.hamias, Ronz, Rosiestep, Rossumcapek, Rotiro, Rsiddharth, Rsrikanth05, Ruinjames, Rursus, Rutger72, Ruud Koot, Rw2, Ryanrs, S.sameermanas, SBunce, SC, SPACEBAR, Sakaal, Salix alba, SamJohnston, Samuraiguy, San2011, Sandipk singh, Sanjiv swarup, Sanmurugesan, Sanspeur, Sapenov, Sarathc, SarekOfVulcan, Sariman, SchreyP, Scientus, Scott A Herbert, ScottSteiner, Scottonsocks, Scwlong, Sean R Fox, Seaphoto, Sebastiangarth, Sfiteditor, Sfoskett, Shadowjams, Shajulin, Shakeelrashed, Shan.rajad23, Sharktopus, Shawnconaway, Shaysom09, Shierro, Shinerunner, Shirt58, Shivalikisam, Shoaibnz, ShortBus, Shri ram r, Shswanson, Shubhi choudhary, Siddii, Silver seren, Simonmartin74, Sissyneck, Sivanesh, Sjames1, Sk8trboi199, Skarebo, Skizzik, Skovigo, Skrewler, Skumarvimal, Skyrail, Slady, Slwri, Smileyranger, Smjg, Snaxe920, Snideology, Snowolf, Snydeq, SoWhy, SocialRadiusOly, Softdevusa, Songjin, Sp33dyphil, SpecMode, Spiritia, Spojrzenie, Sponsion, Sql er2, SqueakBox, Srastogis, Sriharsh1234, Ssabihahmed, Staceyeschneider, Stbrodie1, StefanB sv, Stephan Leeds, Stephenb, SteveLoughran, Steven Walling, Stevenro, Steveozone, Stevevictor134, Stickee, Stickyboi, StrategicBlue, Stuart.clayton.22, Stuartyeates, Subbumv, SudoGhost, Sumdeus, SunnySideOfStreet, Superbeecat, Superm401, Surajpandey10, SuzanneIAM, Sweerek, Swikid, Swolfsg, Syp, TJK4114, Taicl13, Tangurena, TastyPoutine, Tatatemc, Tbhotch, Tdp610, Techman224, Technobadger, TechyOne, Teles, Terrillja, Tgeairn, ThaddeusB, The High Fin Sperm Whale, The Master of Mayhem, The Thing That Should Not Be, The wub, TheNightFly, Thecheesykid, Themfromspace, Thesurfpup, Thewebartists013, Thexman20, ThomasTrappler, Thorwald, Thumperward, Tiburondude, Tide rolls, TimFreeman701, Timwayne, Tinton5, Tisane,

Article Sources and Contributors 26

Tkdcoach, Tmguru, Tobias Bergemann, Tobych, Tom Morris, Tom6, Tomhubbard, Tony1, TonyHagale, Tonyshan, Torturedgenius, Tpbradbury, Tramen12, Tree Hugger, Trusilver, Trödel,Tsmitty31, Tungsten, TutterMouse, Tuwa, TwoTwoHello, TylerFarell, Tylerskf, Ugarit, Ummelgroup, Uncle Dick, UncleBubba, UncleDouggie, Understated1, Undiscovered778, Uozef,Utcursch, ValStepanova, Valenciano, Valentina Ochoa, Vasiliy Faronov, Vasq0123, Veerapatr.k, Vegaswikian, Velella, Vermtt, VernoWhitney, Vertium, VicoSystems1, Victor falk, Vicweast,Vigilius, VijayKrishnaPV, Vipinhari, Viralshah0704, Vishwaraj.anand00, Vmops, Vondruska, Vpfaiz, Vpolavia, Vranak, Vrenator, Wackywace, Waggers, Walshga, Wasami007, Washburnmav,Watal, Wavelength, Waynej6, WeisheitSuchen, Weternuni, Whitecanvas, Whitehatpeople, Whitehouseseo, WikHead, Wiki13, WikiLaurent, WikiPuppies, WikiScrubber, Wikid77, Wikipelli,Willit63, Windchaser, Winterst, Wizzard, Wlouth, WookieInHeat, Wooptoo, WootFTW, Wretman, Wtmitchell, Wtsao, Wtshymanski, Xe7al, Xena77, Xiler, Xinconnu, Xxyt65r, Y2l2,YUL89YYZ, Yaraman, Yaris678, Ycagen, Yerpo, Yinchunxiang, Yodaspirine, Yonidebest, YoungManBlues, Yuchan0803, Yworo, ZX81, Zachnh, Zevnik, Zfish118, Zhanghaisu, Zimzaman,Zingophalitis, Zundark, Zzuuzz, Çalıştay, Σ, 2717 ,דוד שי anonymous edits

Image Sources, Licenses and Contributors 27

Image Sources, Licenses and ContributorsFile:Cloud computing.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Cloud_computing.svg  License: Creative Commons Attribution-Sharealike 3.0  Contributors: Sam JohnstonFile:Cloud computing layers.png  Source: http://en.wikipedia.org/w/index.php?title=File:Cloud_computing_layers.png  License: unknown  Contributors: User:CommonsHelper2 Bot, User:JanLuca, User:Magnus ManskeFile:Cloud computing types.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Cloud_computing_types.svg  License: Creative Commons Attribution-Sharealike 3.0  Contributors: SamJotonFile:CloudComputingSampleArchitecture.svg  Source: http://en.wikipedia.org/w/index.php?title=File:CloudComputingSampleArchitecture.svg  License: Creative Commons Attribution-ShareAlike  Contributors: Sam Johnston, Australian Online Solutions Pty Ltd

License 28

LicenseCreative Commons Attribution-Share Alike 3.0 Unported//creativecommons.org/licenses/by-sa/3.0/