Comparisons

Cloud computing derives characteristics from, but should not be confused with:

1. Autonomic computing — "computer systems capable of self-management".^[8]
2. Client–server model – Client–server computing refers broadly to any distributed application that distinguishes between service providers (servers) and service requesters (clients).^[9]
3. Grid computing — "a form of distributed computing and parallel computing, whereby a 'super and virtual computer' is composed of a cluster of networked, loosely coupled computers acting in concert to perform very large tasks"
4. Mainframe — powerful computers used mainly by large organizations for critical applications, typically bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financialtransaction processing.^[10]
5. Utility computing — the "packaging of computing resources, such as computation and storage, as a metered service similar to a traditional public utility, such as electricity";^[11]
6. Peer-to-peer (disambiguation) – systems in which data transfer utilizes the shared resources of every system attached to the Intranet, setup for a specific task or purpose (ie: BitTorrent (protocol) as one example of many that exist.)

Characteristics

In general, cloud computing customers do not own the physical infrastructure, instead avoiding capital expenditure by renting usage from a third-party provider. They consume resources as a service and pay only for resources that they use. Many cloud-computing offerings employ the utility computing model, which is analogous to how traditional utility services (such as electricity) are consumed, whereas others bill on a subscription basis. Sharing "perishable and intangible" computing power among multiple tenants can improve utilization rates, as servers are not unnecessarily left idle (which can reduce costs significantly while increasing the speed of application development). A side-effect of this approach is that overall computer usage rises dramatically, as customers do not have to engineer for peak load limits.^[12] In addition, "increased high-speed bandwidth" makes it possible to receive the same response times from centralized infrastructure at other sites^[13].

Economics

Cloud computing users can avoid capital expenditure (CapEx) on hardware, software, and services when they pay a provider only for what they use. Consumption is usually billed on a utility (resources consumed, like electricity) orsubscription (time-based, like a newspaper) basis with little or no upfront cost. Other benefits of this time sharing-style approach are low barriers to entry, shared infrastructure and costs, low management overhead, and immediate access to a broad range of applications. In general, users can terminate the contract at any time (thereby avoiding return on investment risk and uncertainty), and the services are often covered by service level agreements (SLAs) with financial penalties.^[14][15]

According to Nicholas Carr, the strategic importance of information technology is diminishing as it becomes standardized and less expensive. He argues that the cloud computing paradigm shift is similar to the displacement ofelectricity generators by electricity grids early in the 20th century.^[16]

Although companies might be able to save on upfront capital expenditures, they might not save much and might actually pay more for operating expenses. In situations where the capital expense would be relatively small, or where the organization has more flexibility in their capital budget than their operating budget, the cloud model might not make great fiscal sense. Other factors impacting the scale of any potential cost savings include the efficiency of a company’s data center as compared to the cloud vendor’s, the company's existing operating costs, the level of adoption of cloud computing, and the type of functionality being hosted in the cloud.^[17][18]

Among the items that some cloud hosts charge for are instances (often with extra charges for high-memory or high-CPU instances); data transfer in and out; storage (measured by the GB-month); I/O requests; PUT requests and GET requests; IP addresses; and load balancing. In some cases, users can bid on instances, with pricing dependent on demand for available instances.

Key features

• Agility improves with users' ability to rapidly and inexpensively re-provision technological infrastructure resources.^[26]
• Cost is claimed to be greatly reduced and capital expenditure is converted to operational expenditure^[27]. This ostensibly lowers barriers to entry, as infrastructure is typically provided by a third-party and does not need to be purchased for one-time or infrequent intensive computing tasks. Pricing on a utility computing basis is fine-grained with usage-based options and fewer IT skills are required for implementation (in-house).^[28]
• Device and location independence^[29] enable users to access systems using a web browser regardless of their location or what device they are using (e.g., PC, mobile). As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet, users can connect from anywhere.^[28]
• Multi-tenancy enables sharing of resources and costs across a large pool of users thus allowing for:
  • Centralization of infrastructure in locations with lower costs (such as real estate, electricity, etc.)
  • Peak-load capacity increases (users need not engineer for highest possible load-levels)
  • Utilization and efficiency improvements for systems that are often only 10–20% utilized.^[22]
• Reliability improves through the use of multiple redundant sites, which makes cloud computing suitable forbusiness continuity and disaster recovery.^[30] Nonetheless, many major cloud computing services have suffered outages, and IT and business managers can at times do little when they are affected.^[31][32]
• Scalability via dynamic ("on-demand") provisioning of resources on a fine-grained, self-service basis near real-time, without users having to engineer for peak loads. Performance is monitored, and consistent and loosely coupled architectures are constructed using web services as the system interface.^[28] One of the most important new methods for overcoming performance bottlenecks for a large class of applications is data parallel programming on a distributed data grid.^[33]
• Security could improve due to centralization of data^[34], increased security-focused resources, etc., but concerns can persist about loss of control over certain sensitive data, and the lack of security for stored kernels^[35]. Security is often as good as or better than under traditional systems, in part because providers are able to devote resources to solving security issues that many customers cannot afford.^[36] Providers typically log accesses, but accessing the audit logs themselves can be difficult or impossible. Furthermore, the complexity of security is greatly increased when data is distributed over a wider area and / or number of devices.
• Maintenance cloud computing applications are easier to maintain, since they don't have to be installed on each user's computer. They are easier to support and to improve since the changes reach the clients instantly.
• Metering cloud computing resources usage should be measurable and should be metered per client and application on daily, weekly, monthly, and annual basis. This will enable clients on choosing the vendor cloud on cost and reliability (QoS).

Layers

Infrastructure

See also: Category:Cloud infrastructure

Cloud infrastructure services or "Infrastructure as a Service (IaaS)" delivers computer infrastructure, typically a platform virtualization environment as a service. Rather than purchasing servers, software, data center space or network equipment, clients instead buy those resources as a fully outsourced service. The service is typically billed on a utility computing basis and amount of resources consumed (and therefore the cost) will typically reflect the level of activity. It is an evolution of virtual private server offerings.^[46]

Server

The servers layer consists of computer hardware and/or computer software products that are specifically designed for the delivery of cloud services, including multi-core processors, cloud-specific operating systems and combined offerings.^{[37][47][48][49]}

Community cloud

A community cloud may be established where several organizations have similar requirements and seek to share infrastructure so as to realize some of the benefits of cloud computing. With the costs spread over fewer users than a public cloud (but more than a single tenant) this option is more expensive but may offer a higher level of privacy, security and/or policy compliance. Examples of community cloudinclude Google's "Gov Cloud".^[50]

Private cloud

Private cloud and internal cloud are neologisms that some vendors have recently used to describe offerings that emulate cloud computing on private networks. These (typically virtualisation automation) products claim to "deliver some benefits of cloud computing without the pitfalls", capitalising on data security, corporate governance, and reliability concerns. They have been criticized on the basis that users "still have to buy, build, and manage them" and as such do not benefit from lower up-front capital costs and less hands-on management^[52], essentially "[lacking] the economic model that makes cloud computing such an intriguing concept".^[54][55]

Issues

Privacy

The Cloud model has been criticized by privacy advocates for the greater ease in which the companies hosting the Cloud services control, and thus, can monitor at will, lawfully or unlawfully, the communication and data stored between the user and the host company. Instances such as the secret NSA program, working with AT&T, and Verizon, which recorded over 10 million phone calls between American citizens, causes uncertainty among privacy advocates, and the greater powers it gives to telecommunication companies to monitor user activity.^[56] While there have been efforts (such as US-EU Safe Harbor) to "harmonise" the legal environment, providers such as Amazon still cater to major markets (typically the United States and the European Union) by deploying local infrastructure and allowing customers to select "availability zones."^[57]

Compliance

In order to obtain compliance with regulations including FISMA, HIPAA and SOX in the US, the Data Protection Directive in the EU and the credit card industry's PCI DSS, users may have to adopt community or hybrid deployment modes which are typically more expensive and may offer restricted benefits. This is how Google is able to "manage and meet additional government policy requirements beyond FISMA"^[58][59] and Rackspace Cloud are able to claim PCIcompliance.^[60] Customers in the EU contracting with Cloud Providers established outside the EU/EEA have to adhere to the EU regulations on export of personal data^[61].

Many providers also obtain SAS 70 Type II certification (e.g. Amazon^[62], Google^[63] and Microsoft^[64]), but this has been criticised on the grounds that the hand-picked set of goals and standards determined by the auditor and the auditee are often not disclosed and can vary widely.^[65] Providers typically make this information available on request, under non-disclosure agreement.^[66]

Legal

In March 2007, Dell applied to trademark the term "cloud computing" (U.S. Trademark 77,139,082) in the United States. The "Notice of Allowance" the company received in July 2008 was cancelled in August, resulting in a formal rejection of the trademark application less than a week later.

Since 2007, the number of trademark filings covering cloud computing brands, goods and services has increased at an almost exponential rate. ^[67] As companies sought to better position themselves for cloud computing branding and marketing efforts, cloud computing trademark filings increased by 483% between 2008 and 2009. ^[68] In 2009, 116 cloud computing trademarks were filed, and trademark analysts predict that over 500 such marks could be filed during 2010.^[69]

Open source

Open standards are critical to the growth of cloud computing, and open source software has provided the foundation for many cloud computing implementations.^[70] In November 2007, the Free Software Foundation released the Affero General Public License, a version of GPLv3 intended to close a perceived legal loophole associated with free softwaredesigned to be run over a network.^[71]

Open standards

See also: Category:Cloud standards

Most cloud providers expose APIs which are typically well-documented (often under a Creative Commons license^[72]) however also unique to their implementation and thus not interoperable. Some vendors have adopted others' APIs^[73]and there are a number of open standards under development, including the OGF's Open Cloud Computing Interface. The Open Cloud Consortium (OCC) ^[74] is working to develop consensus on early cloud computing standards and practices.

Security

Main article: Cloud computing security

The relative security of cloud computing services is a contentious issue which may be delaying its adoption.^[75] Some argue that customer data is more secure when managed internally, while others argue that cloud providers have a strong incentive to maintain trust and as such employ a higher level of security.^[76]

The Cloud Security Alliance is a non-profit organization formed to promote the use of best practices for providing security assurance within Cloud Computing.^[77]

Sustainability

Although cloud computing is often assumed to be a form of "green computing", there is as of yet no published study to substantiate this assumption. ^[78]

Research

A number of universities, vendors and government organizations are investing in research around the topic of cloud computing.^[79] Academic institutions include University of Melbourne (Australia), Georgia Tech, Yale, Wayne State, Virginia Tech, University of Wisconsin Madison, Boston University, Carnegie Mellon, MIT, Indiana University, University of Massachusetts, University of Maryland, North Carolina State, Purdue, University of California, University of Washington, University of Virginia, University of Utah, University of Minnesota, among others.^[80]

Joint government, academic and vendor collaborative research projects include the IBM/Google Academic Cloud Computing Initiative (ACCI). In October 2007 IBM and Google announced the multi- university project designed to enhance students’ technical knowledge to address the challenges of cloud computing.^[81] In April 2009, the National Science Foundation joined the ACCI and awarded approximately $5 million in grants to 14 academic institutions.^[82]

In July 2008, HP, Intel Corporation and Yahoo! announced the creation of a global, multi-data center, open source test bed, called Open Cirrus^[83], designed to encourage research into all aspects of cloud computing, service and data center management.^[84] Open Cirrus partners include the NSF, the University of Illinois (UIUC), Karlsruhe Institute of Technology, the Infocomm Development Authority (IDA) of Singapore, the Electronics and Telecommunications Research Institute (ETRI), the Malaysian Institute for Microelectronic Systems(MIMOS), and the Institute for System Programming at the Russian Academy of Sciences (ISPRAS).^[85]

The Enabling Grids for E-sciencE (EGEE) project provides the world's largest production grid infrastructure for applications for use by more than 10,000 researchers from 50 countries, according to the European Union EGEE Web site.^[86]

The IEEE Technical Committee on Services Computing^[87] in IEEE Computer Society sponsors the IEEE International Conference on Cloud Computing (CLOUD)^[88]. CLOUD 2010 will be held on July 5–10, 2010 in Miami, Florida.

Criticism of the term

Larry Ellison, CEO of Oracle Corporation has stated that cloud computing has been defined as "everything that we already do" and that it will have no effect except to "change the wording on some of our ads"^[89][90]. Oracle Corporationhas since launched a cloud computing center and worldwide tour. Forrester Research Principal Analyst John Rymer dismisses Ellison's remarks by stating that his "comments are complete nonsense and he knows it". ^[91][92][93]

During a video interview, Forrester Research VP Frank Gillett expresses criticism about the nature of and motivations behind the push for cloud computing. He describes what he calls "cloud washing" in the industry whereby companies relabel their products as cloud computing resulting in a lot of marketing innovation on top of real innovation. The result is a lot of overblown hype surrounding cloud computing. Gillett sees cloud computing as revolutionary in the long term but over-hyped and misunderstood in the short term, representing more of a gradual shift in our thinking about computer systems and not a sudden transformational change.^[94][95]

Richard Stallman, founder of the Free Software Foundation and creator of the computer operating system GNU, said that cloud computing was simply a trap aimed at forcing more people to buy into locked, proprietary systems that would cost them more and more over time. "It's stupidity. It's worse than stupidity: it's a marketing hype campaign," he told The Guardian. "Somebody is saying this is inevitable – and whenever you hear somebody saying that, it's very likely to be a set of businesses campaigning to make it true." ^[96]

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Categories: Cloud computing | Centralized computing