Int 16 Fn FFD4  U - PC Tools V5.1-8.0 Desktop - Create/open/delete File    [U]

   AX = FFD4h
   BH = 3Ch create file (with no attributes)
        3Dh open file
        41h delete file
   BL = access mode
        00h read only
        01h write only
        02h read/write
   DS:SI -> ASCIZ filename

Return: BX = file handle
       0000h on error

Note:  operation is attempted in (in order) the directory from which the
     desktop was started/run???, the directory specified with the
     filename, X:\PCTOOLS\, and X:\