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Server Virtualisation Print
October 2006

(for Technical Readers)

Virtualization happens in many facets of information technology such as website, storage, application and machine hardware platform. This article pertains to machine hardware platform although the concept discussed may be applicable to other areas of virtualization.  The incentive for virtualization is to gain independence of a relationship that is otherwise dependent.  In brief terms, there are 3 major layers in a PC or server.  The layers are the hardware, the operating system (OS) and the applications through which human users derive the benefits of having the entire stack. These 3 layers have a tight relationship.  For example the OS is coupled to the machine hardware and is not always transferable to other machine hardware verbatim. It is transferable if the other machine hardware is identical.  Similarly, applications installed on a machine may not run when transferred verbatim to another machine or OS.  There is a dependence on the layer below for enabling proper execution.  Here comes virtualization.  If we insert a layer between the hardware and the OS, the OS would be dependent on the inserted layer and not on the hardware although it is true that the new layer is dependent on the hardware.  The inserted layer would allow OS to be transferable to another inserted layer that is identical, or that is just a virtual incidence of the same inserted layer.  This inserted layer is the Machine Virtual software!  VMWare is the leader of this technology for machines based on x86 architecture and it provides free downloads of some versions of its products.  Microsoft and Xen are the 2 other well known suppliers of machine virtual software.  The attached PDF file provides a more detailed explanation of how virtual software work, what are the cost-benefits of server virtualization, what is the penalty in performance, what is the limitation of compatibility and lastly what the current developments hold for us. Feel free to contact This e-mail address is being protected from spam bots, you need JavaScript enabled to view it   for clarification or to discuss if your school will benefit from virtualization.

pdf 2006-10_machine_virtualisation 236.33 Kb