Xen: http://del.icio.us/rss/tag/xen
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KVM stands for the “Kernel Virtual Machine” and is included in the LInux-kernel as of version 2.6.20.
The kvm wiki. This includes a list of supported KVM guests.
While Red Hat and SUSE prefer Xen, Ubuntu chose in February 2008 to use KVM for virtualization. (Red Hat includes KVM in Fedora)
Guides for using Ubuntu with KVM:
linux
hypervisor
virtualization
KVM
linux-kernel
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