Disk conversion (physical to virtual, and vice versa).
Moving files between a VHD and the host file system.
The ability to directly modify a virtual machine's hard disk from a host server supports many applications, including: This method enables developers to test software on different operating systems without the cost or hassle of installing a second hard disk or partitioning a single hard disk into multiple volumes. A Virtual Hard Disk allows multiple operating systems to reside on a single host machine.