[Coco] Copying over an IO ERROR

Arthur Flexser flexser at fiu.edu
Wed Feb 4 19:54:39 EST 2015


On Tue, Feb 3, 2015 at 11:37 PM, Darren A <mechacoco at gmail.com> wrote:

>
> There is also the problem that the WD17xx floppy controllers leave the
> address mark detector on during the entire Read Track operation.  There are
> certain bit sequences that will trigger a false AM detection. If any of
> these sequences occur within legitimate sector data then all data following
> it up until the next address mark will be garbage (clock bits instead of
> data).
>
> - Darren
>
>
Hard to see why a READ track function would be designed to behave like
that, unless it is for the purpose of allowing software producers a means
of rendering some track data unreadable for copy protection purposes.

Art


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