KVM The Next Best Thing?

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KVM's approach differs from that of Xen, which governs access to hardware using a combination of a lightweight "hypervisor" foundation and a privileged operating system, which is typically Linux. KVM's method is conceptually closer to one of two approaches used by VMware--the "hosted" model used in the free VMware Server and Player products. In that model, guest virtual machines run atop a copy of the operating system. In the second VMware approach, used in the higher-end ESX Server product, a full-featured, heavyweight hypervisor governs access to underlying hardware.