What is Virtual Machine?
A virtual machine is a computer program that not only behaves like an actual computer but also provides functionality and user experience of a separate physical computer. The computer running a virtual machine is known as ‘host’ while the virtual machine is called ‘guest’. A host can operate more than one guest simultaneously. Typically, a virtual machine is an image file that is emulated on a host through virtualisation software known as a virtual machine monitor (VMM) or hypervisor [link to #5.3]. Virtual machines are isolated from rest of the computer and other VMs, and cannot affect programs and functionalities of the host.
Points to Remember
Virtual machines are divided into two categories based on their implemented method and use.
- System Virtual Machines allow multiple guests to share physical resources of the host, enabling each of them to run a separate copy of the operating system. This type of virtualisation is facilitated through a hypervisor that adds a software layer on the actual operating system.
- Process Virtual Machines are created to run a computer program in a platform-independent environment. A process virtual machine only supports one process and functions similar to a computer application.