Re: Pseudo-disk *almost* ready for the big time.

["Alex Freed" <alexf@mirrow.com>]

"Michael J. Mahon" <mjmahon@aol.com> wrote in message
hcednedHRsMoXKDYnZ2dnUVZ_vudnZ2d@comcast.com">news:hcednedHRsMoXKDYnZ2dnUVZ_vudnZ2d@comcast.com...

> First, it captures information that should allow the protected disk
> to be run from other hardware simulating the Disk ][, like a version
> of your card with quarter-tracking and rotation angle simulation.
>

Well, that's what I have all the free space in AVR's flash memory for. The
AVR gets
an interrupt every time a phase is switched. The current firmware only cares
about
EVEN phases switched ON. It can just as easily react to ODD phases for
half-tracks and 2 adjacent phases being "on" for quarter-tracks. It's just
that the .nib format doesn't have anything beyond full tracks, so I ignore
the
extra positioning.

I currently don't simulate the rotation angle, but running at 16 MHz, the
AVR can
create events with a rather fine  granularity. So simulating 40 cycle sync
bytes etc.
is not a problem at all.

Having said that, I'd rather have someone else adding to the open source
firmware
to support fancy copy protection. As I said before I prefer to stick to the
hardware
design.

As a side note, if a physical floppy is connected to my FPGApple it becomes
a
perfect tool for investigating protection methods - I can see inside the
computer
as it is running at full speed. And save a log of all the interesting
operations.

-Alex.