Cloud Computing

Cloud Computing is an emerging computing technology that uses the Internet and central remote servers to maintain data and applications. It allows consumers and businesses to use applications without installation and access their personal files at any computer with Internet access. This technology allows for much more efficient computing by centralizing storage, memory, processing and bandwidth. Cloud computing is broken down into three segments: "Application-as-a-Service (SaaS)", "Platform-as-a-Service (PaaS)" and "Infrastructure-as-a-Service (IaaS)". Each segment serves a different purpose and offers different products for businesses and individuals around the world.

A Typical Cloud Computing System

Software-as-a-Service (SaaS):

So far the applications segment of cloud computing is the only segment that has proven successful as a business model. By running business applications over the Internet from centralized servers rather than from on-site servers, companies can cut some serious costs. Furthermore, while avoiding maintenance costs, licensing costs and the costs of the hardware required to run servers on-site, companies are able to run applications much more efficiently from a computing standpoint.

On Demand software services come in a few different varieties that vary in their pricing scheme and how the software is delivered to the end users. In the past, the end-user would generally purchase a license from the software provider and then install and run the software directly from on-premise servers. Using an On-Demand service however, the end-user pays the software provider a subscription fee for the service. The software is hosted directly from the software providers' servers and is accessed by the end user over the Internet. While this is the most common platform for On Demand software services, there are also some slightly different offerings that can be described as a hybrid of these two platforms. For instance, a program through which the end user pays a license fee, but then accesses the software over the Internet from centralized servers is considered a hybrid service.

Who is offering SaaS? - The companies below are already established in the On-Demand software or SaaS business. These companies charge their customers a subscription fee and in return host software on central servers that are accessed by the end user via the Internet.

• Salesforce.com
• Google
• NetSuite
• Taleo
• Concur Technologies

Platform-as-a-Service (PaaS):

Many of the companies that started out providing On Demand application services have developed platform services as well. The platform segment of cloud computing refers to products that are used to deploy applications. Platforms serve as an interface for users to access applications provided by partners or in some cases the customers. Some examples included Salesforce.com's platform force.com, which allows subscribers to access their applications over the Internet. NetSuite, Amazon, Google, and Microsoft have also developed platforms that allow users to access applications from centralized servers.

Active platforms - The following companies are some that have developed platforms that allow end users to access applications from centralized servers using the Internet. Next to each company is the name of their platform.

• Google – Apps Engine
• Amazon.com – EC2
• Microsoft – Windows Live
• Terremark Worldwide – The Enterprise Cloud
• Salesforce.com – Force.com
• NetSuite – Suiteflex
• Rackspace Cloud – cloudservers, cloudsites, cloudfiles
• Metrisoft – Metrisoft SaaS Platform

Infrastructure-as-a-Service (IaaS):

The final segment in cloud computing, known as the Infrastructure, is very much the backbone of the entire concept. Infrastructure vendors provide the physical storage space and processing capabilities that allow for the all the services described above. The products in this segment are slightly more varied than those in the other areas of cloud computing but include ones such as managed hosting, and development environments (such as Google gears) that allow users to build applications. Cloud storage, such as Amazon’s S3, is also considered to be part of the infrastructure segment.

Major Infrastructures Vendors - Below are companies that provide IaaS services:

• Google – Managed hosting, development environment
• International Business Machines (IBM) – Managed hosting
• SAVVIS – Managed hosting
• Terremark Worldwide – Managed hosting
• Amazon.com – Cloud Storage
• Rackspace Hosting – Managed hosting & cloud computing