Int 21 Fn 440D  - Ms-dos 7.0 - Generic Ioctl - Get First Cluster           [D]

   AX = 440Dh
   CX = 0871h (category code 08h, minor code 71h)
   BX = filename character set (see #1265)
   DS:DX -> ASCIZ pathname for file or directory

Return: CF set on error
       AX = error code (01h,02h,etc.) (see #1366 at AH=59h/BX=0000h)
   CF clear if successful
       DX:AX = first cluster number

Note:  this function finds any file or directory regardless of attributes,
     except that it will not find volume labels

See Also: AX=440Dh"DOS 3.2+",AX=440Dh/CX=086Ch,#1041

(Table 1265)
Values for character set:
 00h   Windows ANSI
 01h   current OEM character set
 02h   Unicode