Re: Looking for "Ultima II" .nib images

["Michael J. Mahon" <mjmahon@aol.com>]

sicklittlemonkey wrote:
> > Stephen Thomas has written a *very* short, but sophisiticated,
> > DPLL-type track read routine that determines the length of mixed 8-,
> > 9-, and 10-bit nibbles on the fly.  I'll ask him if he'd like to publish it.
>
>
> Sounds interesting.
>
>
> > But this kind of bit stuffing to adjust track length (as opposed to
> > tweaking the disk speed) can interfere with some copy protection
> > schemes that look for nibble lengths as part of a signature.
>
>
> Well if you're trying to write the exact same number of nibbles, some
> variable has to change. Drive speed is not so convenient for most
> people, I suppose - it's that 0.1% you mentioned. ;-)

But there is no choice except to adjust drive speed if the
disk signature involves both the number of nibbles and
their length in bit cells.

This is why so many people put external speed adjustments
on their disk drives at one time.

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it is seriously underused."