How to determine Hyper-V hostname inside the guest VM

On Hyper-V virtual machine with integration services installed the host machine can be identified by reading HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Virtual Machine\Guest\Parameters\Hostname on the guest machine itself.

Reference(s):

http://social.technet.microsoft.com/wiki/contents/articles/219.hyper-v-how-to-find-the-host-of-a-vm.aspx