Virtualisation is easier to understand if you’ve seen the film The Matrix.

There’s our hero (Neo) living his life, eating. drinking, sleeping, going to work, renting a nice apartment, seeing his friends, thinking life is pretty good. But in reality he is a body floating in a tank with tubes stuck in him. What he thought was his world is really a dream created by a computer, a virtual world.

Author William Gibson is credited with inventing the term “cyber-space” to describe virtual reality in his book Neuromancer.

What’s this got to do with us and why is it important? Hang in there.

A virtual computer is an artificial one created inside another. The real computer is called the host and the fake is called the virtual one.

So what looks like Windows XP running on a Dell PC could really be a virtual PC running inside a Mac. This lets you have your Windows programs and use them on your Mac. There’s a program called Parallels that makes this possible.

In the Enterprise world, they virtualise the servers. So what looks like your file server is just a virtual server running on a bunch of hardware. They can move the server to any physical box just by drag and drop. And if they set it up properly those boxes could be spread across data centres in different places. So if the power is going off in Hobart, you can move your servers to Launceston by drag and drop, with no loss of data and no interruption to service. The users would never know.

Another use is in disaster recovery. Acronis lets you take a backup copy of your server and if the server dies, you can run the copy on any other computer because Acronis makes a virtual server inside the replacement. The backup copy doesn’t know the difference, it thinks its still on the original hardware. So the copy of your HP server will happily run inside a Dell machine even though the servers are nothing alike. They call it Universal Restore.

On the desktop, you could take a dangerous program like Internet Explorer and run it inside a virtual PC on your computer. IE would think it had full run of a PC but really be constrained inside the fake one. If it got infected with malware, you could just shut down the virtual PC and it would vanish and your host PC would not be affected. Because to the host, the virtual PC is just another program. Sand Box IE does this.