Massimo Re Ferrè has written a nice overview article on hypervisor architecture:
It is my feeling that there has been a bit of confusion lately around how hypervisors are being positioned by the various vendors. I am specifically referring to the three major technologies that seem to be the most relevant strategically going forward:
- VMware ESX
- Microsoft Viridian
VMware ESX is the VMware flagship hypervisor product: it's the basis for the Virtual Infrastructure version 3 framework.
MS Viridian is the next generation hypervisor that Microsoft is going to use in the Longhorn time frame and that is currently being developed. It's basically the successor of Microsoft Virtual Server.
Xen is an opensource hypervisor that is being integrated by a number of players which include RedHat, Suse, XenSource and Virtual Iron.
Read the article here