Usually the bully kicks sand in the little guy's face, but VMware is switching that story. In a speech at LinuxWorld in August, VMware chief scientist Mendel Rosenblum talked up application-specific operating systems provided by ISVs that would run on a hypervisor--no general-purpose OS needed. You can bet Microsoft took notice.

For IT pros, it was smack talk worthy of Terrell Owens. Rosenblum has cause to be cocky. VMware's dazzling partial initial public offering has filled its coffers with almost a billion dollars, and its hypervisor market share looks insurmountable. Meanwhile, Microsoft's Windows Server 2008, which has yet to take the field, won't include a hypervisor until six months after the server launches.

But Bill Gates didn't get to be the richest man in the world by eating dirt. Just ask Steve Jobs and Marc Andreessen. Although both execs have rehabilitated themselves in other environs, the butts of the Mac OS and the Netscape browser remain decisively kicked.

Gates' team has played this game before--a nimble competitor with innovative technology eventually gets crushed by the slow but inexorable force of Microsoft's market dominance (abetted by sometimes unsavory business practices). But this time, the ending might be different because virtualization fundamentally changes the rules. Microsoft's tried-and-true strategy may not work, in part because what gives Microsoft its strength--the operating system--is losing its clout.

That's because the general-purpose operating system is being squeezed from above and below. Application vendors can build their own microkernels designed to run in a virtual environment, knocking the conventional OS right off the server.

Second--and perhaps more significant--the hypervisor is becoming the main mediator among the components of a data center ecosystem. Large and small vendors alike are building or enhancing their product lines to tap into the hypervisor as a control point, for tracking resource use, provisioning and moving virtual machines, and tying into storage systems.

These developments don't preclude an operating system, but they do minimize its influence, especially as more enterprises embrace the full promise of virtualization--generalized pools of resources that can be applied on demand to various business needs.

In this environment, the operating system is locked inside a virtual machine and shipped from resource pool to resource pool like cargo on a container ship, captained by the hypervisor.

We'll look at how virtualization changes the game and examine VMware's prospects for dominating the server environment and sidelining the operating system.