Int 16 Fn FF70  U - PC Tools V8+ Drivemap - ???                            [d]

   AX = FF70h
   BX = 0002h
   CX = ???
   DX = ???

Return: AX = ??? or FFFEh/FFFFh on error
   DL = ???
BUG:   DRIVEMAP will branch to random locations for BX values other than
     those listed above for v8.0-9.0 because a) the incorrect register is
     range-tested, resulting in BX=0003h-5CD6h being accepted as valid
     function numbers, and b) the conditional which branches on invalid
     function numbers jumps to the following instruction, becoming a NOP

See Also: INT 2F/AX=9203h"DRIVEMAP"
Index: installation check;DRIVEMAP