Date   : Wed, 24 Mar 2010 08:21:07 -0000
From   : dl.harper@... (David Harper)
Subject: Re-using floppies

Rick Murray wrote

>> Then there's flippy disks which have two sync holes so you can flip them
>> over, I seem to remeber these being used on the Commodore PET.
>
> I would have thought two sync holes would be a problem whichever way the
> disc was!
>
> Perhaps you mean the notch cut in the jacket? I have, someplace, a
> number of commercial Beeb discs that were double-face, formatted 40
> track on one side and 80 track on the other, same stuff in each case.

There was only one hole in the disc, but two in the jacket - to align with 
the detector whichever way up it the disc was. There were usually two 
write-protect notches too.

David Harper