What is Cloud Computing?

Posted on February 23, 2010 | What at mybiginfo.com | What is Cloud Computing? | | View all What | |

Cloud computing is a general term for anything that involves delivering hosted services over the Internet. These services are broadly divided into three categories: Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). The name cloud computing was inspired by the cloud symbol that’s often used to represent the Internet in flow charts and diagrams.

A cloud service has three distinct characteristics that differentiate it from traditional hosting:

1.It is sold on demand, typically by the minute or the hour.
2.It is elastic — a user can have as much or as little of a service as they want at any given time.
3.The service is fully managed by the provider (the consumer needs nothing but a personal computer and Internet access).

A cloud can be private or public. A public cloud sells services to anyone on the Internet. (Currently, Amazon Web Services is the largest public cloud provider.)

A private cloud is a proprietary network or a data center that supplies hosted services to a limited number of people. When a service provider uses public cloud resources to create their private cloud, the result is called a virtual private cloud. Private or public, the goal of cloud computing is to provide easy, scalable access to computing resources and IT services.

History

The underlying concept of cloud computing dates back to 1960, when John McCarthy opined that “computation may someday be organized as a public utility”; indeed it shares characteristics with service bureaus that date back to the 1960s. The actual term “cloud” borrows from telephony in that telecommunications companies, who until the 1990′s primarily offered dedicated point-to-point data circuits, began offering Virtual Private Network (VPN) services with comparable quality of service but at a much lower cost. By switching traffic to balance utilization as they saw fit they were able to utilise their overall network bandwidth more effectively. The cloud symbol was used to denote the demarcation point between that which which was the responsibility of the provider from that of the user. Cloud computing extends this boundary to cover servers as well as the network infrastructure.

Amazon played a key role in the development of cloud computing by modernizing their data centers after the dot-com bubble, which, like most computer networks, were using as little as 10% of their capacity at any one time just to leave room for occasional spikes. Having found that the new cloud architecture resulted in significant internal efficiency improvements whereby small, fast-moving “two-pizza teams” could add new features faster and easier, Amazon started providing access to their systems through Amazon Web Services on a utility computing basis in 2005.This characterization of the genesis of Amazon Web Services has been characterized as an extreme over-simplification by a technical contributor to the Amazon Web Services project.
In 2007, Google, IBM, and a number of universities embarked on a large scale cloud computing research project.

Architecture

Cloud architecture,the systems architecture of the software systems involved in the delivery of cloud computing, comprises hardware and software designed by a cloud architect who typically works for a cloud integrator. It typically involves multiple cloud components communicating with each other over application programming interfaces, usually web services.

This closely resembles the Unix philosophy of having multiple programs each doing one thing well and working together over universal interfaces. Complexity is controlled and the resulting systems are more manageable than their monolithic counterparts.

Cloud architecture extends to the client, where web browsers and/or software applications access cloud applications.
Cloud storage architecture is loosely coupled, often assiduously avoiding the use of centralized metadata servers which can become bottlenecks. This enables the data nodes to scale into the hundreds, each independently delivering data to applications or users.

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