Cloud computing is getting a lot of play recently but, for many, the cloud is still a bit, well, cloudy. In this blog I will put some parameters around what we call cloud, I will touch on three cloud service models and discuss 2 commercial implementations from Amazon and Microsoft.

The National Institute for Standards and Technology defines cloud computing as follows: Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction (http://www.nist.gov/customcf/get_pdf.cfm?pub_id=909024).

The cloud model is composed of three service models.

Cloud Software as a Service (SaaS). Hosted software services running on a cloud infrastructure.

Cloud Platform as a Service (PaaS). Cloud-based platform where users can deploy and run applications designed for the hosting platform.

Cloud Infrastructure as a Service (IaaS). The provisioning of processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications.   This cloud model promotes availability and is composed of five essential characteristics that include On-demand self-service, broad network access, resource pooling, rapid elasticity and measured service.These characteristics could benifit business in the ways of cost-saving, opportunity to focus on core competency rather than IT and mobilization of workforce.