Everybody is sure that cloud computing is key to the future of IT, but people often seem unsure quite what it is. In fact, it’s an umbrella term for a number of different trends, all involving the internet and its potential to simplify the way we use computers and extend their capabilities.
The “CLOUD” is the internet, and the term is fitting – it’s large, out there somewhere, and fuzzy at the edges. Cloud computing is about putting more of your material out there and less on PCs or servers that a business runs for itself.
You can do this in many ways, but with every vendor claiming to do cloud computing in some form it has become confusing. It is worth understanding terms such as SaaS (software-as-a- service) and PaaS (platform-as a-service) so as to evaluate vendor claims. There are radical differences between the various forms of cloud computing, and they do not all offer the same benefits.
The Point for Cloud computing, reasons vary, but often include the desire to outsource the maintenance burden of servers and applications; the need to scale systems up or down on demand; the benefit of being able to access your data from anywhere with an internet connection; and the ability to replace occasional heavy expenditure on IT with regular and predictable operational expenditure.
The idea for Utility computing is that businesses should not be spending effort and money on installing and maintaining complex hardware and applications, when a specialist can supply those same services on a pay-as- you-go basis. Businesses do not generally generate their own power – utilities are bought when needed. In the same way, the argument runs, essential IT services can be managed better externally.
The software-as-a-service (SaaS) is a Pre-baked services that you access simply by navigating there in a web browser.
The platform-as-a-service (PaaS) is a set of lower-level services such as an operating system or computer language interpreter or web server offered by a cloud provider, on which developers can build custom applications.
Infrastructure-as-a-service (IaaS) means the provision of servers or virtual servers that organisations use on a pay-as- you-go basis. Amazon’s Elastic Compute Cloud (EC2) is an example of IaaS. In practice, cloud suppliers often provide additional services alongside IaaS offerings, so the boundary between IaaS and PaaS is ill-defined.
The rich internet application (RIA) is a modern web browsers have fast script engines and rich graphics and plug-ins, such as Adobe Flash, to extend their capabilities. A rich internet application has applications running in the browser that have rich graphics and the kind of sophisticated user interface that at one time would only have been possible in a locally installed desktop application. The term was made popular by Adobe for applications using its Flash plug-in, but it is also sometimes used to describe advanced HTML applications.
Multi-tenancy is a Cloud-hosted applications where multiple customers share a single application, even though they only have access to their own data. Salesforce.com is an example. Multi- tenancy is the most cost-effective form of cloud computing, since the software itself is shared.
The difference between public, private and hybrid clouds is some organisations, especially larger ones, want the benefits of cloud computing but without the risks inherent in trusting their data to a third party. They can achieve this by creating a cloud-like infrastructure in their own data center. This is called a private cloud. The public cloud refers to providers such as Amazon, Google and salesforce.com, whose shared services are available to all. A hybrid approach uses both public and private services.
Virtualisation is emulating computer hardware in software, so that one or more emulated computers can run simultaneously on a single physical computer. This is a boon for cloud computing: service providers can use hardware efficiently by running many virtual servers on each machine in a data center. Sometimes virtual machines can be moved between company premises and cloud providers.
Is Cloud computing green? Well cloud computing goes some way towards solving a problem called under- utilisation, where servers run constantly with little computing load, wasting money and power. Service providers use virtualisation and other techniques to make full use of their hardware. The downside is that these datacenters are power-hungry, and we are using more of them as demand grows. The hope is that a new generation of more efficient super computers will make cloud computing a truly green option.
One will ask if there are any risks in cloud. Cloud computing has real benefits, but there are also reasons for caution. Risks include loss of service if your provider has downtime or goes out of business, regulatory problems when personal data is stored internationally, security concerns when users lose control of how their data is protected, one-sided service agreements that give users little redress in the event of a calamity, and lock-in dependency on proprietary cloud applications