What is a Windows Computer?

This seems at first a silly question. But to understand what a virtualized computer is, it is first necessary to understand what we are virtualizing.

A computer consists of

  1. Hardware
    1. CPU
    2. Memory
    3. Bus
    4. Network adapter
    5. Hard drives
  2. Operating system – in this case Windows
  3. Drivers – little bits of code to connect the Hardware with the Operating system
  4. Applications that run within the operating system

The idea of virtualization is that a physical computer – the host which has all of these features has in addition software known as a hypervisor.

The hypervisor can be set up to emulate hardware – it can synthesize all of the hardware mentioned above so that an operating system can be installed to this synthesized (virtualized) computer known as the guest

In essence ,the guest is simply a configuration file, and a virtual hard drive file. The hardware is now just an xml file and the c drive is just a single file on the host. The host can have many guests – ultimately limited by the quality and quantity of host hardware and the load of each guest.

It should be obvious that a Windows 2016 server on physical hardware will be faster than a Windows 2016 virtual guest running on a Windows 2016 virtual host. The performance penalty for this scenario is however small but rapidly increases with increasing numbers of guests on a single host.

There are many advantages though of a virtualized environment – especially when considering disaster recovery.