85. Disc drive hints
    ~~~~~~~~~~~~~~~~
*BACKUP produces a duplicate of the original disc, with all the files,
(programs), in the same order on the disc. *COPY, on the other hand, reverses
the order on the disc. The catalogue will not show this up, as it is always
in alphabetical order, but you can tell if you use *COMPACT or *INFO.

If you use a '*' command which none of the ROMs recognize, then the Acorn
DFS's will attempt to *RUN a file of that name. If the file is not a
machine-code routine, then the attempt will fail. However, the Watford
DFS's go one step further, because they will *EXEC the file if it is text,
(ie if it has been SPOOLed onto disc).

This was written before the Master and the 1770 DFS came out. I think 
that they too are semi-intelligent in this situation.