I am not a betting man (I paid attention in class when we covered probability) but I would bet that virtualization will change everything.

I concluded last week's column with the prediction that virtualization would make the server business more cutthroat than it already is.

My reasoning was that when hardware is isolated from the operating systems to the extent that it is effectively generic and any physical differences are transparent, server differentiation becomes impossible and branding irrelevant.

My second thought about virtualization is potentially more disruptive: A virtualized infrastructure weakens Microsoft's hegemony.

Note that I'm not taking Microsoft's foray into virtualization, Microsoft Virtual PC, seriously. When I talk about virtualization I'm talking about the likes of VMware. The biggest difference between Microsoft's product and VMware is the latter's support for non-Windows operating systems, notably the 57 varieties of Linux, as well as NetWare and exotica such as Oberon, Inferno and BeOS. Virtual PC, on the other hand, is really more of a migration tool for NT 4 shops.

In the Microsoft world, the intimate relationship with the underlying hardware makes the operating system special - Windows is "welded" to the platform, and the complexity of the resulting system means you have to be committed to the installation.

But virtualization changes everything. Now operating systems become as mobile and malleable as applications - in fact operating systems become, in practice, even more mobile than applications, and can be duplicated, relocated and reconfigured with amazing ease.

So if Microsoft doesn't own the platform any more, it puts the company in a weaker position. For example, where you need extra service and don't want to spend more money on Windows, you can run an alternative operating system simply configured for one or two services. This really will rattle Microsoft's ongoing spin-doctoring about the total cost of ownership of Windows compared with Linux.

If you take a Windows shop and try to migrate to Linux the cost will kill you, but that isn't reality. Reality is that you would use your existing investment and over a long period introduce Linux piecemeal. With virtualization, the migration process becomes far more manageable and therefore cost-effective.