Virtualization is the creation of a virtual (rather than actual) version of something, such as an operating system, a server, a storage device or network resources. Operating system virtualization is the use of software to allow a piece of hardware to run multiple operating system images at the same time. The technology got its start on mainframes decades ago, allowing administrators to avoid wasting expensive processing power.
In 2005, virtualization software was adopted faster than anyone imagined, including the experts. There are three areas of IT where virtualization is making head roads, network virtualization, storage virtualization and server virtualization.