A virtual machine is a software, that lets you create and run a separate operating system in your existing computer system. You can boot the virtual machine from the parent operating system and run just like another software application.

For example: If you are using Windows xp, you can install popular virtualization software like Windows virtual PC, Vmware workstation to create a virtual machine within your current operating system. Now in that virtual machine, you can install any operating system e.g Windows xp, vista. You can run these operating systems in a new explorer window within Windows xp.

The problem with virtual machines is that you have to install an operating system from scratch. This includes loading the operating system from cd or dvd, installing all the drivers and system software etc. This can be very time consuming and is not a quick job.

A few weeks ago, I wrote an article on How To Run Multiple X Sessions Without Virtualization, which demonstrated how you can run multiple desktop environments at the same time on the same computer, and switch between them at the push of a button. I admit, this was somewhat of a warmup for the real show – how to run multiple Linux distributions at the same time without having to deal with the drawbacks of virtualization software.

Today, we’re going to be using chroot to treat certain parts of your Linux filesystem as (almost) completely isolated systems. This can let you do all kinds of interesting things, like run a full Gentoo system from inside your Ubuntu system with little to no performance loss.

One of the best things about a Linux system is its flexibility. Even though I’ve been a heavy Linux user for years, I still come across features in the OS a related applications that surprise me. A while back I learned to run multiple desktop environments at the same time, using nothing but the features of the software already built in to my distribution, and it’s been very useful for me. It may not sound like much, but it can be VERY useful to be able to run Gnome, KDE, Window Maker, and any other desktops all at the same time. You can flip from Gnome to Window Maker in seconds without having to log out or stop applications or use any kind of virtualization software. X already has everything you need.

Virtualbox is an excellent application to have if you’re looking to try out new operating systems and/or are generally interested in virtualisation for the many benefits it offers.

Make Tech Easier has extensively covered VirtualBox a couple of times earlier and we are great fans of this cross platform, open source application.

One thing which VirtualBox was missing till some time back was support for 3D acceleration for guest operating systems. What this means is that the graphics driver used inside the guest virtual machines was only capable of simple 2D graphics and thus interfaces like Compiz on Linux and Aero on Vista were not useable.

There was basic 3D support for Windows guests in Virtualbox 2.1 but users using Virtualbox to run Linux guests were mostly confined to the 2D graphics driver. That has changed with the release of VirtualBox 2.2 recently and VirtualBox now supports 3D acceleration. The 3D acceleration support built in VirtualBox uses your native machine’s graphics hardware to provide this capability, so if your native graphics driver doesn’t have 3D capability, VirtualBox cannot make use of it.

QEMU is a CPU and process emulator which allows you to create virtual machines that can run on any platform. QEMU manager uses this emulator to virtualize Linux on windows systems. In this post we show you how to create an Ubuntu virtual machine on Windows using QEMU manager.