[Coco] Re: Oddball disk format question
robert.gault at worldnet.att.net
Tue Nov 23 09:18:44 EST 2004
Torsten Dittel wrote:
> The more I think about it the more I'm sure the sequence you're
> describing could be created using a "killer" bit sequence. I have to
> think about how it worked (has to do with MFM coding). Just so far: What
> you're reading with READTRACK is *NOT* what was written with WRITETRACK.
> Some of the bytes are "faked" by these killer bits which are interpreted
> as a syncing signal due to a "bug" of the controller (I think it's on
> purpose the READTRACK doesn't work properly to allow copy protection
I know that some of the bytes are faked. I've stated how the 248 sector
number can be created and the CRC for the track ID can be inserted
manually. I just don't see how the data was created to include $A1, $F5,
$F6, and $F7.
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