Virtualization is the technology that hides the physical characteristics
of a computing platform from the users, instead presenting an
abstract, emulated computing platform [52]. This emulated computing
platform for all practical purposes behaves like an independent
system, but unlike a physical system, can be configured on demand,
and maintained and replicated very easily. The computing infrastructure
is much better utilized, leading to lower upfront and operational
costs (one side benefit of virtualization is the savings in real estate for
the data centers). While the concept of virtualization has been
prevalent since the 1960s, it is only in the recent past that computing
power and networking resources have caught up to deliver the level
of seamless performance within an emulated system that users have
grown accustomed to on personal computers