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What is virtualization?

Akhilesh Trivedi
Ranch Hand

Joined: Jun 22, 2005
Posts: 1599
I came across VMWare somewhere here. I would like to know what exactly happens in virtualization, both in terms of hardware and software.
I have two operating systems on my PC, says windows and linux, and a boot-loaded to give control which one to boot, how does virtualization differ from this kind of environment?

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Joe Ess

Joined: Oct 29, 2001
Posts: 9190

In a dual boot system, you are only running a single operating system at a time. In order to switch OS's, you need to reboot.
In a virtualized system, there is a single host OS which runs the virutalization software (VMWare, VirtualBox). This software creates a "virtual machine" which can boot up into a separate operating system (to run Linux on Windows and vice versa, for example). You can run several virtual machines/OS's at the same time and switch between them freely. This is actually an old idea, going back to 1960's mainframes which has gotten new life in the modern data center.
Personally, I use it for testing my applications on various OS's and for server consolidation.
As for what happens at the hardware/software layer, I'm clueless. You can start with this article and follow the links.
[ October 22, 2008: Message edited by: Joe Ess ]

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Akhilesh Trivedi
Ranch Hand

Joined: Jun 22, 2005
Posts: 1599
So in a virtualized environment, one step above the applications is the operating system, and one step above the operating systems is the Virtualization System. Thanks much there are still more queries bubbling let me go around and have a feel of it.
I agree. Here's the link:
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