Microsoft Corp. intends to snare the lion's share of the 90-plus percent of servers that have not yet been virtualized. So says Larry Orecklin, general manager for System Center marketing. And the way the company will hunt down those servers is by giving away Hyper-V, Microsoft's virtualization technology. It will ship in final form as part of Windows Server 2008 in July. But, despite the right price for Hyper-V, Orecklin will never achieve his lofty goal.

That's not because of Microsoft's technology. Hyper-V is a solid-looking approach to virtualization, using the same "microkernelized" method that Xen does. VMware uses a monolithic approach. The main difference is that drivers in the microkernelized world remain part of the guest operating system, while in the monolithic way, drivers are written for the hypervisor. According to Arun Jayendran, senior product manager at Microsoft, a microkernelized hypervisor "has a minimal attack surface" for malware because it eliminates the extra layer for drivers, which have been popular point of entry for hackers.