Virtual Device Drivers
Virtual device drivers represent a particular variant of device drivers. They are used to emulate a hardware device, particularly in virtualization environments, for example when a DOS program is run on a Microsoft Windows computer or when a guest operating system is run on, for example, a Xen host. Instead of enabling the guest operating system to dialog with hardware, virtual device drivers take the opposite role and emulate a piece of hardware, so that the guest operating system and its drivers running inside a virtual machine can have the illusion of accessing real hardware. Attempts by the guest operating system to access the hardware are routed to the virtual device driver in the host operating system as e.g. function calls. The virtual device driver can also send simulated processor-level events like interrupts into the virtual machine.
Virtual devices may also operate in a non-virtualized environment. For example a virtual network adapter is used with a virtual private network, while a virtual disk device is used with iSCSI. The best example for virtual device drivers can be "Daemon Tools".
There are several variants of virtual device drivers.
Read more about this topic: Device Driver
Famous quotes containing the words virtual and/or device:
“Tragedy dramatizes human life as potentiality and fulfillment. Its virtual future, or Destiny, is therefore quite different from that created in comedy. Comic Destiny is Fortune—what the world will bring, and the man will take or miss, encounter or escape; tragic Destiny is what the man brings, and the world will demand of him. That is his Fate.”
—Susanne K. Langer (1895–1985)
“UG [universal grammar] may be regarded as a characterization of the genetically determined language faculty. One may think of this faculty as a ‘language acquisition device,’ an innate component of the human mind that yields a particular language through interaction with present experience, a device that converts experience into a system of knowledge attained: knowledge of one or another language.”
—Noam Chomsky (b. 1928)