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 a hypervisor. Virtual machines are isolated from the 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 the 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.