Re: Write Signal on Disk II Question




Right, but each "1" shows up as a 1us pulse on the read data line.

On my computer, I need ~650ns to read from the parallel port.
This means that I can't read the signal from an original Disk II
reliably if it don't process it.
But while I was experimenting with modern 3.5 '' drives on the Apple
(I just finished it) it found out that the pulse can be much longer
(3µs) without problems. So I would use a monoflop to make the pulse
~2µs long so that I can read it without problems.
But: According to "Understanding the Apple ][" the problem in
detecting more than 2 adjacent zero bits is not in the controller, but
in the drive. If that is true (I could test it - my 3.5'' drives CAN
read more zeroes). We're not improving anything if we're thinking
about other controllers.
And if a copy protected disk works using the Disk ][ controller card
it CAN be read. If it can't be copied this can't really be the
controller's problem.


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