Re: Serial line Burstnibbler, Was: [...] 0.4.0 of opencbm [...]

Pete Rittwage <rcade@xxxxxxxxxxxx> writes:

Dag Lem wrote:

Can you tell me a bit about signature tracks? To begin with, what is
a
signature track? :-)


It's just a track that's written in a funny way that is detected by
copy protection- they typically don't contain data. EA used
"Pirateslayer" which you can read about on my site- it's basically a
syncless track with a certain byte pattern that is searched for.
Other protections used similar techniques either searching for only
one byte or a couple in a certain order.

Ah, OK. If the entire track contains just one or very few consecutive
bytes, then I agree that finding the correct alignment may be
problematic. In this case, you may get several possible alignments,
and you can't really tell which one is correct.

I suppose some heuristics can be used here, e.g. set bits should most
probably be concentrated into as few bytes as possible. Granted, this
won't be foolproof, but perhaps it can drive down the number of
uncopyable disks to a handful or so. I haven't analyzed whether it
would work for "Pirateslayer", perhaps you want to look into that ;-)

--
Dag Lem <resid@xxxxxxxxx>
.

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