Virtualization has revolutionized the IT industry, especially after the launch  of specialized processors around 2006-2007.  The ever increasing need for higher availability, scalability, better performance and more storage has met the demand for lower IT expenditure, better utilization of hardware and energy savings and quite importantly, with improved manageability.  Virtualization has provided the foundation for cloud computing and introduced terms such as Software as a Service (Saas), Platform as a Service (PaaS), even Infrastructure as a Service(IaaS).

In this article, we will examine the various virtualization technologies and the pros and cons of each one, without going into comparing specific vendor offerings.