INT 42 - Western Digital WD1002 SuperBIOS - INT 40 CASCADE                      
Note:	if the second WD1002 controller in the system finds INT 40 already in
	  use, it uses this vector to cascade to the first controller's BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly.
SeeAlso: INT 40"DISKETTE",INT 47"SuperBIOS"