What is Cloud Computing?

Cloud Computing is a marketing buzz-word that got accepted as definition of services built on top of hardware capacities: computing, storage and network.

• Services are provided on-demand; without the need of up-front investments into a datacenter.
• Hardware management is abstracted from the customers.
• Infrastructure capacities are elastic and can easily scale up and down.

Cloud Computing Services can be grouped into three broad categories:

• Infrastructure as a Service (IaaS), where customer gets raw hardware resources: virtual machines, cloud storage space, networking capabilities.
• Platform as a Service (PaaS), where service provider builds a platform to simplify solving some technological tasks. This simplifies life for the customer, but also comes with a lock-down cost.
• Software as a Service (SaaS). At this level everything is way simpler for the customers to consume, since they are provided with actual services generating business value to them. Service providers handle all the technological complexity and provide the support as needed.

Infrastructure as a Service Providers

• Amazon Web Services - scalable Xen-based virtual machines available on per-hour bases. They also have S3 Storage offer.
• Rackspace Cloud Servers and Files – Xen based virtual machines available per-hour.

Platform as a Service Providers

• Microsoft Windows Azure - .NET driven and Microsoft-owned cloud infrastructure.
• Google App Engine - Python-based cloud framework.
• Heroku – Popular Cloud Platform for Ruby-on-Rails. Known for simplicity and ease of use.

Software as a Service Providers

• Windows Live Mesh
• Lokad Forecasting Services – Scalable online business intelligence and sales forecasting.
• Salesforce.com