Run virtual machines without a host

I know that I can have virtualization software (Virtual Box, Virtual PC) running on Ubuntu or Windows and run guest operating systems in it. Is it possible to run virtual machines without a host OS?

Thanks in advance. I am not very familiar with virtualization. Sorry if it is a basic question. I couldn't find an answer on Google. If you can point me to something free that would be great!


A couple of free, bare-metal virtualization software options:

  • VMWare ESXi
  • Microsoft Hyper-V Server 2008

http://www.xen.org/ for linux?


Basically, there are two kinds of hypervisors. First there are the hypervisors that run on top of your operating system. These are called Type-2 hypervisors and include VMware Workstation, MS Virtual PC and VirtualBox. Then, there are the hypervisors that are an operating system (I know that is over-simplified). These are called Type-1 hypervisors and include Xen, Linux w/ KVM, VirtualIron, ESX, ESXi and MS Hyper-V.

What comes closest to what you want, is a Type-1 hypervisor. Judging you from your question, you are going to have a hard time with just about everything save for ESXi with its web interface. I'd go for that if you want decent performance and the option of a broad variation of guest operating systems. ESXi is a bit picky for the underlying hardware though, so if that is a problem, look into Fedora w/ KVM and / or Windows 2008 with Hyper-V. Latest option is pretty expensive though, if you do not have a Windows 2008 license already.


Take a look at these wikipedia articles:

  • Platform virtualization
  • Hypervisor

Microsoft has a hypervisor called Hyper-V.


A virutual machine relies on the host machine, and its OS, to provide access to the host machine's physical CPU, memory, disk drives and other peripherals.

So, no, you cannot run a virtual machine without a host machine and its OS.