What is Virtualisation and how can it help a small business?
Richard Fieldhouse (15/03/11)
The old-style office environment
A traditional PC has a central processing unit - the CPU, and long and short-term memory. These are marshalled together by an operating system, normally Microsoft's Windows, to present the screen and the user interface we are familiar with.
When the machine is turned off, all the user's documents, and all the machine's own settings are stored in its long-term memory - the hard drive, often also called the hard disk.
Introducing Virtualisation
It is possible to convert the PC into a virtual machine. Essentially, this process involves taking a copy of the hard drive as it is when the machine is switched off and moving that to another machine - the physical host machine.
In the host there is special software (for instance VMWare's ESXi) that will mimic the real physical things that were available in the old PC and that the new virtual machine (VM) no longer has access to. The new VM can now be switched on in its new virtual environment, and its operating system will believe that it's running just as it was before.
Can we get at the new VM? Yes. We can replace the big, old, complex PC on the desk with a tiny new one - maybe even a tablet.
This new machine only needs to run a little piece of software to communicate with the virtual host. The host sends us the pictures that the VM is sending to its virtual screen and our little local machine puts those pictures on our screen. In the same way our key presses on our local keyboard are sent back via the host to the VM.
Why would we do this? In essence, it allows the big, hot and expensive components in the virtual host to be shared between many VMs. These valuable components are then more effectively utilised. In addition, when a VM is stopped it becomes little more than a file on the virtual host. By copying this file, the VM is backed up. Or, in the same way, the VM can be moved to a new virtual host. And how can this help the small business? An old-style PC sits in the office all the time and demands to be lavished with constant care and attention. In particular,
it frequently requires updates,
it's hard to take a proper backup copy of the setup while it's running and
it does not like being turned off and on.
This latter problem often results in the PC being left on all the time and exacerbates another of the old fat PC's weaknesses - its greedy appetite for electricity.
While the virtualised office does not solve all these problems overnight, it really can help.
