uIEC/SD == AWESOME!

[Philip Belben]

Apologies for replying to my own post, but...

> Commodore drives do some strange things with GPIB addressing.  Bit 7 
> isn't supposed to be used, but I think Commodore use it to add a flag to 
> the primary address when opening files.  ISTR they may even use bit 6 
> this way, thus preventing you from having a device at (disk drive)+16.

If I had engaged brain before opening text editor, I would have realised 
that this is bit 4 that is being misused.  Bits 5 and 6 are correctly 
used to say what sort of address it is - talk, listen, secondary.

Philip.