Virtualization Essentials

Understanding the Role of a Hypervisor

The explanation of a hypervisor up to this point has been fairly simple: it is a layer of software that sits between the hardware and the one or more virtual machines that it supports. Its job is also fairly simple. The three characteristics defined by Popek and Goldberg illustrate these tasks:

• Provide an environment identical to the physical environment
• Provide that environment with minimal performance cost
• Retain complete control of the system resources

Holodecks and Traffic Cops

In order for many guests to share the physical resources of a host, two things must happen. The first thing is that from the guest’s perspective, it has to see and have access to the various hardware resources it needs to function ...