DOS Fn 0fH: Open File via FCB

                                                         Compatibility: 1.0+ 
 Expects: AH    0fH
          DS:DX address of an unopened FCB
 Returns: AL    0     if file opened without error (and FCB is updated)
                0ffH  if error occurred and file could not be opened
    Info: The file specified by the unopened FCB must already exist in the
          default directory on the drive specified in the FCB (0=default,
          1=A, 2=B, etc).  If not found, AL=0ffH upon return.

          The file is opened in compatibility Access Mode.

          In the FCB, if the bDrvID field is 0 before the call, it is
          filled with the drive number of the default disk (1=A, 2=B,

          The FCB curBlk field is set to 0.
          The FCB recSize field is set to 80H.
          The FCB file size and date are set from info in the directory

   Notes: ■ As with all FCB functions, this works only for files in the
            current directory.
          ■ The handle-oriented functions are MUCH easier to use.

See Also: DOS fn 3dh (open file via handle)
          FCB File I/O
          Handle-Oriented File I/O
          Directory and File Functions
          DOS Functions