INT 66 - Microsoft Windows VITD.386 Virtual Interval Timer                      
Note:	This Windows 3.x Virtual Device DriverAn interface module between the device-independent portions of the operating system and an actual hardware device which converts device-independent requests into the actual sequence of device operations to perform the requested action.  IO.SYS contains the standard, built-in MSDOS device drivers such as CON, COM1, AUX, PRN, etc.  See also INT 21h Function 52h and INT 2Fh Function 0802h. implements a virtual timer
	  which will expire and call INT 66.  This timer can be used to
	  calculate elapsed execution time etc.