The new architecture of synthetic devices with Hyper-V poses some unique challenges for system administrators. Specifically, how can a system administrator perform maintenance on a Hyper-V host from WinPE? Without the integration components, users are required to move their VHD's around to the IDE controller, which limits the amount of VHD's that can be used at any given point in time. Additionally, legacy network adapters might need to be added to the VM to provide network access.
However, by adding the integration components to a WinPE image, those are no longer concerns.
For those of you not familiar with WinPE, here's a brief overview:
Windows Preinstallation Environment (Windows PE) is a minimal operating system designed to prepare a computer for Windows installation. It can be used to start a computer with no operating system (a bare-metal system), to partition and to format hard drives, and to copy disk images or to initiate Windows Setup from a network share. Windows PE is available as a stand-alone product to customers with the proper licensing agreement. It is an integrated component of many Windows Setup and recovery technologies, including Setup for Windows Vista and Windows Deployment Services (WDS).
Windows PE 2.1 is the latest release based on the Microsoft® Windows Vista® operating system.