Virtual Machine (VM)
A virtual machine is a software program that acts as a virtual computer providing the same functionalities of a physical computer.
It runs on our current operating system (the host operating system)
With VM, we can able to create a computer within a computer.
The end user has the same experience on a virtual machine as they would have on dedicated hardware.
Virtual machines are often created to perform certain tasks that are different than tasks performed in a host environment.
Multiple virtual machines can run simultaneously on the same physical computer.
Each virtual machine provides its own virtual hardware, including CPUs, memory, hard drives, network interfaces and other devices — for instance, a virtual machine’s virtual hard disk is stored in a file located on our hard drive.
Guest Operating System
The virtual machine represents virtual hardware on which a guest operating system runs.
The guest OS, typically Windows or Linux, is installed into a virtual machine much the same way that it is installed on a traditional physical machine.
The guest OS can be different than the host OS i.e., guest OS can be a Linux running on Windows host OS.
A guest OS hosted on a virtual machine can be used for testing without having an impact to the host OS.
Hypervisor
A hypervisor or virtual machine monitor (VMM) is computer software or firmware that creates and runs virtual machines.
The hypervisor presents the guest operating systems with a virtual operating platform and manages the execution of the guest operating systems.
Hypervisors can be divided into two types:
Type 1: Also known as native or bare-metal hypervisors which run directly on the host computer’s hardware to control the hardware resources and to manage guest operating systems. Examples: HyperKit for MacOS, Hyper-V for Windows and KVM for Linux.
Type 2: Also known as hosted hypervisors run within a formal operating system. Examples: VirtualBox and VMWare.
Advantages of VM
VM uses virtual hardware which is 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.
