Virtualization is about creating virtual (rather than actual) versions of computer hardware, operating systems, storage devices, and computer network resources. This enables users to run multiple operating systems and multiple applications on the same server at the same time. Virtualization can be categorized into different layers: desktop, server, file, storage and network.
The technology behind virtualization is known as a virtual machine monitor (VMM) or virtual manager, which separates computer environments from the actual physical infrastructure. Virtualization enables businesses to reduce IT costs while increasing the efficiency, utilization and flexibility of their existing computer hardware.