u8526425
Wiki was written very clearly
A hypervisor or virtual machine monitor (VMM) is a piece of computer software, firmware or hardware that creates and runs virtual machines.
I suggest that every thing about IT resource explanation
U just type key word,then,search in wiki
it will show the appropriate answer On your searching device
Hypervisor
http://en.wikipedia.org/wiki/Hypervisor
既然知道是伺服器了,還不算作業系統嗎!?