A while ago I posted an original guide to Hyper-V Terminology.  Well, there have been a couple of new terms that have come on to the scene that I would like to clarify for people:

• Microsoft Hyper-V Server
  
  When you see people talk about “Microsoft Hyper-V Server” they are talking about the stand alone version of Hyper-V.  The simple rule here is the “Microsoft” means that you are not talking about a full Windows installation.  From a Microsoft lexicon point of view software is either part of Windows – and gets the Windows naming (e.g. Windows Powershell) or is not part of Windows and gets the Microsoft naming (e.g. Microsoft Office).
  
  
• Windows Server 2008 without Hyper-V
  
  This is an actual name of a Windows SKU and refers to a version of Windows Server 2008 which does not include any Hyper-V components.  Note that people are often tripped up by the fact that this also means that there are no Hyper-V management tools in this SKU.
  
  
• Hyper-V on Windows Server 2008 / Windows Server 2008 with the Hyper-V role enabled
  
  The part is a little clumsy.  While we have the “Windows Server 2008 without Hyper-V” SKU, its alternative is just “Windows Server 2008”.  But in order to avoid confusing people into thinking there is another SKU you will never see Microsoft say “Windows Server 2008 with Hyper-V” as that sounds to close to the aforementioned SKU name.  As a result you will see the above terms used to refer to a Windows Server 2008 system that has Hyper-V enabled (as compared to a Windows Server 2008 system that does not have Hyper-V enabled).
  
  
• Hyper-V
  
  This is a generic term to refer to the Hyper-V technology, whether it is Hyper-V on Windows Server 2008 or Microsoft Hyper-V Server.
  
  
• Management Operating System
  
  This is a new term that we are introducing in Windows Server 2008 R2.  We have been struggling without a good term here – as with Virtual PC / Virtual Server we had a nice set of terms where we could talk about the physical computer / virtual machine and the host operating system / guest operating system.  However this became muddier with Hyper-V – because we no longer really have a host operating system, and all operating systems run on top of the hypervisor.  Most people have been just using the term “Parent” or “Parent partition” to refer to what we used to call the host operating system – but this is not really architecturally correct.  Unfortunately the architecturally correct terms are – frankly – hideous; they are the “parent partition guest operating system” and the “child partition guest operating system”.  Yuck.  So after a lot of thought we decided to call the “parent partition guest operating system” the “Management operating system” as this is the operating system you use to manage your virtual machines, and “guest operating system” will be reserved to mean the operating system running inside virtual machines.

Cheers,
Ben