Cloud Computing Is Based On A Robust Architecture

One vision of the twenty first century computing is that users will access Internet services over lightweight portable devices rather than through some descendant of the traditional desktop personal computer or PC. Because users would not have powerful machines or would not be interested in using powerful machines, the computing power would be supplied through cloud computing.

Cloud computing is a recent trend in information technology or IT that moves computing and data away from desktop and portable personal computers or PCs into the large data center facilities maintained by the application hosting and cloud computing service providers. Cloud computing or cloud hosting refers to applications (QuickBooks, Peachtree, Drake tax software, etc.) delivered as services over the Internet as well as to the actual cloud infrastructure, namely, the hardware and systems software in data center facilities that provide these services. The key driving forces behind the cloud computing technology are the ubiquity of broadband and wireless networking, falling storage costs, and progressive improvements in Internet computing software. Clients of a Cloud hosting service provider are able to add more capacity at peak demand, reduce costs, experiment with new services, and remove unneeded capacity, whereas service providers are able to increase utilization via multiplexing, and allow for larger investments in software and hardware. Currently, the main technical underpinnings of cloud computing infrastructure and services include virtualization, service oriented software, grid computing technologies, management of large facilities, and power efficiency.

Consumers purchase such services in the form of the infrastructure as a Service (IaaS), platform as a Service (PaaS), or software as a Service (SaaS) and sell value added services, such as utility services, to users. Within the cloud, the laws of probability give service providers great leverage through the statistical multiplexing of varying workloads and easier management; as a single software installation can cover many users needs. One can distinguish two different architectural models for clouds - the first one is designed to scale out by providing additional computing instances on demand. Clouds can use these instances to supply services in the form of SaaS and PaaS.

The second architectural model is designed to provide data and compute intensive applications via scaling capacity. In most cases, clouds provide on demand computing instances or capacities with a pay as you go economic model. The cloud infrastructure can support any computing model compatible with loosely coupled central processing unit or CPU clusters. Organizations can provide hardware for clouds internally (called as internal clouds), or a third party can provide it externally (called as hosted clouds). A cloud might be restricted to a single organization or group (called as private clouds), available to the general public over the Internet (called as public clouds), or shared by multiple groups or organizations (called as hybrid clouds). A cloud comprises processing, network, and storage elements, and cloud computing architecture consists of three abstract layers. Infrastructure is the lowest layer and is a means of delivering basic storage and compute capabilities as standardized services over the network. Servers, storage systems, switches, routers, and other systems handle specific types of workloads, from batch processing to server or storage augmentation during peak loads. The middle platform layer provides higher abstractions and services to develop, test, deploy, host, and maintain applications in the same integrated development environment. The application layer is the highest layer and features a complete application(e.g. Quickbooks Enterprise solutions, MS Project, MS office etc.) offered as a service.