What Is a Virtual Machine? Definition & Guide

What is a virtual machine? definition & guide 

A virtual machine, or VM, is a software-defined computer that exists only as code within a physical server. It is a digital version of a physical computer and works just like a computer within a computer. 

The virtual environment runs on an isolated partition of the host computer and has its own operating system, CPU power, memory, disks for file storage, ability to connect to the internet, and other necessary resources. 

Virtualisation is the process of creating a virtual version of a computer that functions like a physical computer. A virtual machine uses software to run programs and deploy apps instead of a physical computer. 

Virtual guest machines operate within a physical host machine. This can be useful both in the cloud and across on-premises environments. 

Using VMs can be more cost-effective, provide resources to multiple users at the same time and in different locations, be more efficient, and offer increased flexibility.

What are virtual machines?

A software-based digital computing system, a virtual machine (VM) can perform all of the functions of a physical computer. 

VMs use the resources of a physical “host” computer and/or a remote server to run as a virtual “guest.” This digital version of a physical computer, the virtual machine, is a computer file called an image that acts like a regular computer. The VM will borrow a set amount of CPU, storage, and memory from its physical host and run in an isolated partition separate from the host.

The virtual machine can function as a replacement for a physical computer, or it can run as a separate computing environment in a separate window, often to allow for the use of an alternative operating system to the host. Virtual machines do not interfere with the host computer’s operating system and therefore can often be used for software or application testing. 

Virtual machines are often deployed to allow for remote use and have enabled cloud computing to take off.

How virtual machines work

Virtual machines use virtualisation technology, which works to create a virtual, software-based computer. Resources are provisioned from the host to the guest — a process that is managed by software called a hypervisor. The hypervisor ensures that operations are scheduled so the host and the guest (physical computer and virtual machine) can work in tandem without disrupting each other. 

Virtual machines can exist on a physical computer host or a remote server, such as one in a cloud provider’s data centre, for example. These VMs function the same as an actual computer and commonly run in an application window or on the operating system of a physical machine. 

Types of virtual machines

There are two main types of virtual machines: process VMs and system VMs. 

A process VM provides a platform-independent programming environment. The process virtual machine allows a single process to run as an application on the host machine while ignoring information on the underlying operating system or hardware. This can allow a machine to run an application on a host machine that the operating system typically does not support.

A system VM is a complete substitution of a physical machine, and it is fully virtualised. A host computer’s physical resources can be shared between various virtual machines, each of which is running its own copy of the operating system on the system platform. The hypervisor runs on top of the operating system or on bare hardware to complete the virtualisation process.

5 types of virtualisation

The components that make up an IT infrastructure or that make up a traditional data centre can be virtualised. Here are five specific types of virtualisation:

1. Network virtualisation: Companies with a high volume of users who need constant access to a network can benefit from network virtualisation. This type of virtualisation allows multiple sub-networks to be created on the same physical network. The equipment is combined into one software-based virtual network.

   Bandwidth can also be divided into multiple independent channels that are assigned individually to servers and devices. Network virtualisation can increase network speed, reliability, and security, and it can allow for improved monitoring of data usage.

2. Hardware virtualisation: Also known as server virtualisation, hardware virtualisation creates virtual versions of operating systems and computers and consolidates them into one primary physical server. The virtual machines are managed by a hypervisor that communicates with the physical CPU and server’s disk space. 

   With hardware virtualisation, multiple operating systems can be run on one machine, and hardware resources are used more efficiently.

3. Software virtualisation: A computer system complete with hardware is created with software virtualisation to allow a guest operating system (or more than one) to run on a physical host machine using the same hardware.

   Applications are also able to be virtualised and then delivered from a server to an end user’s device. Software virtualisation allows remote users to access centrally hosted applications.

4. Desktop virtualisation: With desktop virtualisation, the desktop environment is separated from the physical device and stored on a remote server. Users are then able to access their desktop on any de