[Coco] Re: Oddball disk format question

Torsten Dittel Torsten at Dittel.info
Tue Nov 23 03:50:17 EST 2004


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
schemes).

Torsten




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