INT 21 - DOS 1+ - CREATE OR TRUNCATE FILE USING FCB
        AH = 16h
        DS:DX -> unopened FCB (see AH=0Fh), wildcards not allowed
Return: AL = status
            00h successful
            FFh directory full or file exists and is read-only or locked
Notes:  if file already exists, it is truncated to zero length
        if an extended FCB is used, the file is given the attribute in the
          FCB
        not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=10h,AH=3Ch