System Virtualization: Multi-OS or Multitask?

System virtualization is not a new concept, with roots dating back to the
beginnings of modern computing.  Present-day system virtualization is heavily
centered around server consolidation and running multiple multitasking operating
systems on the same physical computer; however, system virtualization has not
always been as OS-centric as it is today.  Historic hypervisor development
centered around the problem of multitasking in a stable and robust way, and was
largely dependent upon the early co-evolution of hardware and software.  In the
modern virtualization world, a growing interest in system virtualization on
commodity hardware has led to another period of co-evolution between hardware
and software, causing technologies like Intel's VT-* and AMD's SVM to emerge on
the x86 and x86_64 architectures.  We challenge the current view of system
virtualization by examining how this modern co-evolution could enable system
virtualization to be used for multitasking on commodity hardware, and discuss
the costs and benefits of doing so