While virtual machines run like individual computers with individual operating systems and applications, they have the advantage of remaining completely independent of one another and the physical host machine. A piece of software called a hypervisor, or virtual machine manager, lets you run different operating systems on different virtual machines at the same time. This makes it possible to run Linux VMs, for example, on a Windows OS, or to run an earlier version of Windows on more current Windows OS.
And, because VMs are independent of each other, they're also extremely portable. You can move a VM on a hypervisor to another hypervisor on a completely different machine almost instantaneously.
