We Know about partition physical hard disk drives on our Computers. But then, how does a VHD (Virtual hard disk) differ from the physical hard disk? Here we go. VHDs are mainly used as hard disks for Virtual Computers. They completely mimic what the hard disks in our computers have.VHDs too have the same directory structure which is composed of files and folders and the disk partitions. If it has the same structure, you might wonder why you would ever require a separate VHD.