Int 2F Fn 4A11  - Dblspace.bin - "dsgetentrypoints" - Get Device Driver E  [d]

   AX = 4A11h
   BX = 0003h
   CL = drive number (0=A:) of compressed drive

Return: CL = FFh on error (not compressed drive)
      = other driver unit number of host drive
       ES:SI -> device driver's strategy routine
       ES:DI -> device driver's interrupt routine
   BX destroyed

Note:  in conjunction with subfunction 0004h, this call allows disk caches
     like SMARTDRV to apply a device driver wrapper to DoubleSpaced
     drives just like SMARTDRV applies to regular block devices

See Also: AX=4A10h/BX=0007h,AX=4A11h/BX=0000h,AX=4A11h/BX=0004h