Configuring Item-level recovery for Hyper-V ( misunderstanding.)

Hi ,

Using DPM 2012  , Configuring Item-level recovery for Hyper-V

Based on this article http://technet.microsoft.com/en-us/library/hh757981.aspx

it say  "If you use a version of Windows Server before Windows Server 2008, you must have the Hyper-V role enabled on the DPM server to perform item-level recoveries. During item-level recovery, DPM has to mount the VHDs of the protected virtual machines."

What is meaning of windows server before windows 2008  , it is for the DPM itself or the hyper-V host server

and how to enable hyper-v role on "Windows Server before Windows Server 2008"

I don't understand  which server it mean ?

thanks

another article"http://technet.microsoft.com/en-us/library/hh758184.aspx"

Server prerequisites

Install the Hyper-V role on the DPM server. DPM protects Hyper-V virtual machines even without the role, but you cannot perform item-level recovery (ILR) unless the role is installed.