Int 40  - Acorn Bbc Master 512 - "osfind" - Open File                      [O]

   AL = operation
       00h close file
       40h open file for reading
       80h open file for writing
       C0h open file for random access
   DS:BX -> CR-terminated filename

Return: AL = file handle (00h if file closed or could not be opened)

Note:  the Acorn BBC Master 512 is an 80186-based add-on board for the
     6502-based Master 128 which uses the original CPU as an I/O processor

See Also: INT 41"Acorn",INT 42"Acorn",INT 43"Acorn",INT 44"Acorn",INT 4C"Acorn"