Over 40 years ago IBM invented virtualization on MainFrames in order to resolve inefficiencies around low CPU utilization and operational system complexity.

In 1998, Professor Mendel Rosenblum of Stanford University and a couple of his graduate students founded VMware in order to address similar problems in the X86 architecture.  This began the growth of x86 based hypervisors with open source community and entrprenures developing compelling technologies to do more with less.

VMware, Citrix, and Virtual Iron as well as other x86 virtualization product ("hypervisors") offer a “bare metal” microkernel operating system.  OS based hypervisor only function is to deliver server resources; CPU, RAM and I/O efficiently up to the individual virtual machines. Hypervisors that are OS dependant may have limitations and decereased performance, but provides the flexibility to evaluate, and test virtualization technology with small or no budget impacts.