Virtualization was one of the buzzwords of last year, but it is more than just a buzzword. VMware had a successful IPO last year, and they have a pretty solid set of virtualization products, among them VMware Workstation. Microsoft is also serious about virtualization. They made their Virtual PC product free, and have released a Virtual Server (VMware has 2 or 3 flavors of Virtual Server). Then there are Parallels and VMware Fusion for the Mac.

So what is virtualization? In its simplest form it is creating a Virtual Computer using software, which runs on a physical computer. I’m using the term Virtual Computer instead of Virtual Machine as Virtual Machine can mean something totally different in Windows. This Virtual Computer uses some elements of the physical computer, like RAM, optical drives, network cards and hard drive space to make the virtual computer. When an Operating System is installed on the Virtual Computer, it thinks it is being installed on a physical computer. In fact, the process of setting up Windows XP for example, is almost exactly the same on a Virtual Computer as on a physical computer. When software is installed on the Virtual Computer’s Operating System, it generally doesn’t know the difference.

The benefits of this are numerous. For software testing it is a great tool, as you can rollback any changes made to the Virtual Computer. Multiple different operating Systems can be run on one Physical Machine, which then has to have sufficient disk space and extra RAM. For example if I need to run a program which only runs on Windows 98, instead of having a physical machine dedicated to this, it can run in a Virtual Computer running Windows 98 on a Windows XP desktop.

The real benefits of virtualization are when multiple physical servers are consolidated onto one physical server which then runs multiple virtual servers.

Posted on February 23rd, 2008 by mervyn