VMware continues to dominate the data center on the strength of its vSphere server virtualization platform, but Microsoft’s Windows Server 2012 is coming on strong. Citrix, meanwhile, continues to lead the desktop virtualization space but has been steadily adding to its portfolio of cloud and mobility offerings.

Within the legions of smaller virtualization vendors, the focus these days is squarely on managing the technological complexity that comes as virtual and cloud environments scale. Cross-hypervisor management was one of the biggest trends to emerge during 2012 and is sure to continue commanding attention this year.

Here we at look at the 20 virtualization providers included in this year's Data Center 100.