Final answer:
A Pass-through Disk is a type of virtual disk that allows a virtual machine to directly access a physical disk drive. This can lead to improved disk I/O performance but also comes with limitations compared to traditional virtual hard disks, such as the inability to use snapshots and differencing disks.
Step-by-step explanation:
The type of virtual disk that points to a physical disk drive, rather than an area of space on a physical disk, is known as Pass-through Disk or sometimes referred to as direct-attached storage. This configuration allows a virtual machine to access a physical disk directly, which can be beneficial for applications that require direct access to the storage media. Unlike traditional virtual hard disks (VHDs or VHDXs) which are stored as files on the host system and represent a portion of physical disk space, pass-through disks are not limited to the file-based structure and can provide better disk I/O performance.
However, while performance may be enhanced, there are trade-offs in terms of flexibility and portability. For instance, pass-through disks cannot utilize features like snapshots and differencing disks, which are available with VHDs. Furthermore, the physical disk must be taken offline from the host operating system before it can be used as a pass-through disk, ensuring exclusive access for the virtual machine.