What is a virtual machine?
A virtual machine is a computer file, typically called an image, that behaves like an actual computer. In other words, a computer is created within a computer. It runs in a window, much like any other program, giving the end user the same experience on a virtual machine as they would have on the host operating system itself. The virtual machine is sandboxed from the rest of the system, meaning that the software inside a virtual machine can’t escape or tamper with the computer itself. This produces an ideal environment for testing other operating systems including beta releases, accessing virus-infected data, creating operating system backups and running software or applications on operating systems they weren’t originally intended for.
Multiple virtual machines can run simultaneously on the same physical computer. For servers, the multiple operating systems run side by side with a piece of software called a hypervisor to manage them, while desktop computers typical employ one operating system to run the other operating systems within its program windows. Each virtual machine provides its own virtual hardware, including CPUs, memory, hard drives, network interfaces and other devices. The virtual hardware is then mapped to the real hardware on the physical machine which saves costs by reducing the need for physical hardware systems along with the associated maintenance costs that go with it, plus reduces power and cooling demand.