"Like dinosaurs in their time, the monolithic, commercial operating systems (OSes) have ruled their world for an age. Server virtualization has heralded a new era, however, and OSes as we have known them probably won't thrive in it.
"As its uses continue to grow, server virtualization will pose a major threat to the strategic position that the general-purpose operating system has long held in the x86 software stack. In this situation, Microsoft in particular has a lot to lose. So do Linux and Unix vendors, but these OSes do have advantages in a virtualization setting..."