What is a virtual machine

Have you heard about your virtual machine geek friend and the topic intrigues you but you still don’t know what a virtual machine is and above all what it allows you to do? Know that knowing what a virtual machine is is very useful because this technology will literally open up new horizons for you. This is not new, indeed virtual machines have already existed for a long time but if you still don’t know them and you don’t know what they can do then dedicate a few minutes of your life to me, it’s really worth it! I promise you that I will try to explain what a virtual machine is, avoiding unnecessary digressions and without being too technical.

Index

• What is a virtual machine
• Software to create virtual machines
  • VMWare (Windows, Mac)
  • Virtual Box (Windows, Mac, Linux)
  • Parallels (Mac)
  • QEMU (Windows, Mac, Linux)
  • Hyper-V (Windows)

What is a virtual machine

So let’s start to see what a virtual machine is and then understand what it is for. We can say very crudely that virtual machines are “virtual computers” that you can install on a physical computer using specific software. It is therefore a computer file, which behaves like a real computer.

A virtual machine is made up of files that are read by particular software and behaves like a real computer with its own operating system.

So on your home computer you can install virtualization software and put one or more virtual machines on it. For example on a Mac (with Intel processor) you can put a Windows virtual machine through the VMWare or Parallels software; in this Windows virtual machine (which takes the name of guest ) you can run any Windows program and use it exactly as you do with a Windows PC. The physical computer hosting the virtual machines is called Host .

Usually a virtual machine is composed of a virtual disk file (whose size depends on the size of the disks you assign when the machine is created) and one or more configuration files.

Obviously a virtual machine is less efficient and slower than a physical computer; it is absurd to think, for example, of creating a Windows virtual machine for gaming because the virtual machine hardware is fully emulated and will not be able to offer high performance.

Now that you know what a virtual machine is, let’s try to understand what they are for. But first it is worth specifying that you can:

• create a virtual machine from scratch (a new computer)
• create a virtual machine by cloning an existing physical machine

For example, if you are afraid that your old PC is about to abandon you, you can clone it and put it as a virtual machine on your new computer.

Virtual machines are extremely useful for creating development environments, for cloning computers, for trying new operating systems and so on.

A great advantage of virtual machines is the management of backups; you can perform some sort of full backup of a virtual machine (called snapshot ) with a simple click and switch between backups in real time. The operation is extremely fast and practical.

Software to create virtual machines

Now that you know roughly what a virtual machine is, let’s see what are the software to create them. Nowadays you will find a lot of virtualization software; some for a fee and others for free but just as valid

VMWare (Windows, Mac)

VMWare is the most used virtualization software in the professional field. It is available for Windows and Mac. On Windows there is both a free version called VMware Player and a paid version called VMware Workstation ; the main difference between the two is that in the paid version there are more features.

On mac VMWare takes the name of VMWare Fusion and is available both in the free VMWare Fusion Player version and in the paid version VMWare Fusion 12 Pro . VMWare on Mac allows you to run windows directly from the mac but only on Apple computers with an Intel processor (does not work on M1 processors).

Virtual Box (Windows, Mac, Linux)

The most widely used completely free virtualization software is Virtual Box . Although free, this software has absolutely nothing to envy to paid virtualization software; it has all the features you need including excellent snapshot management and integration between guest and host computers. Virtual Box allows you to create “portable” virtual machines that you can insert into USB sticks and run when you need them on any workstation you want; in this case you will need to download Virtualbox Portable .

Parallels (Mac)

Parallels is the most used virtualization software on Mac computers but it does not exist in a free version (except for the trial version limited in time) and its license costs 79.99 euros for private use.

QEMU (Windows, Mac, Linux)

QEMU (short for  Quick EMUlator ) is a very powerful virtualization software because it allows you to virtualize even machines with different architecture from the one where it is installed (virtualize x86, AMD64, PowerPC, MIPS and ARM architectures). QEMU was born for Linux but currently there are also distributions for Windows and Mac. It is an excellent alternative to VirtualBox and differs from this because it is more complex to use but it is more powerful. It also allows you to create portable virtual machines (which you can safely keep on a USB stick and start on any PC without having to install any special software.

Hyper-V (Windows)

Another free virtualization software is Microsoft’s Hyper-V ( Windows Server Virtualization ) which allows you to create virtual machines (Windows machines only) on computers with Windows operating systems. Hyper-V is completely free and available starting from Windows 8 or on server systems from Windows Server 2012.

Now that you know what a virtual machine is and how useful it can be, all you have to do is download a virtualization software and get started right away. You can create a virtual computer on your USB key and always carry it with you to always have your workstation wherever you are. In addition to virtual machines, you can take a look at this page to discover the world of emulators as well.