Virtual device driver for Windows systems
VXD is a file extension for the virtual device driver program in many Windows operating systems.
A device driver is a program that maintains the status of hardware devices with changeable settings. The device driver controls a specific device attached to your computer by translating the operating system's input/output (I/O) instructions to messages that device can understand.
A virtual device driver handles software interrupts from the operating system for each of the computer's main hardware devices, including the hard disk drive controller, keyboard, and serial and parallel ports. Regular (non-virtual) device drivers handle hardware interrupts.
Learn more about VXD files:
Serdar Yegulalp explains saving and restoring device drivers on Windows PCs.
Search for the answers to VXD questions on IT Knowledge Exchange.
PCauthorities.com explains what virtual device drivers are and how they work.