Components

Components of Cloud Computing

There are three major forms of cloud computing in use today, utility computing, platform as a service (PaaS), and cloud-based applications.

Utility Computing

Utility computing focuses on “developers, not end-users” (O'Reilly). “Amazon's success in providing virtual machine instances, storage, and computation at pay-as-you-go utility pricing was the breakthrough in this category, and now everyone wants to play” (O'Reilly). Amazon web services™ offers two products in the utility computing category, Amazon S3 and Amazon EC2. “Amazon S3 is storage for the Internet” (Simple). “Amazon Elastic Compute Cloud (Elastic) is a web service that provides resizable compute capacity in the cloud” (Elastic). They transfer data “between Amazon EC2 and Amazon S3 within the same region is free of charge,” making Amazon S3 the obvious data storage choice for an EC2 based system.

Platform as a Service (PaaS)

Platform as a service, or PaaS, hide the machine instances, and instead provide a platform to host an application in the cloud instead of a computing instance (O'Reilly). Google's App Engine is a prime example of a PaaS. Tim O'Reilly stated in his article on October 26th, 2008, titled Web 2.0 and Cloud Computing, that “many of the applications being deployed there seem trivial compared to the substantial applications being deployed on the Amazon and force.com platforms.” However, “with App Engine, you only pay for what you use” (Google). “App Engine costs nothing to get started. All applications can use up to 500 MB of storage and enough CPU and bandwidth to support an efficient app serving around 5 million page views a month, absolutely free” (Google). Serving applications for free may reduce the quality of the work because the people using the platform may only be interested in cost.

Cloud-based applications

According to Tim O'Reilly, “any web application is a cloud application in the sense that it resides in the cloud. Google, Amazon, Facebook, twitter, flickr, and virtually every other Web 2.0 application is a cloud application in this sense” (O'Reilly). However, if an application resides in the cloud, it does not mean it is distributed across the cloud. Cloud-based applications not only reside in the cloud, but use part of the cloud's distributed network to provide its application. Flickr is a prime example of a cloud-based application. It has a distributed network of servers to host and provide the application that allows it to be fast and efficient (Huff).