(VxD) A device driver unDER {Windows 3.x}/{Windows 95} running as part of the {kernel} and thus having access to the memory of the kernel and all running processes as well as raw access to the hardware. VxD' s usually have the filename extension .386 unDER Windows 3.x and .vxd unDER Windows 95. VxD' s written for Windows 3.x can be used unDER Windows 95 but not vice versa. (1997-02-27)