Question about a copy protection, Contra Copy

[hyperactive]

Hi there.
I can remember, about 15 years ago, there was a product that you could download that would copy protect floppies. There was even a demonstration program you could run to write out to a 3.5 inch disk, and when you ran it, it would detect if you were using an original disk.
It was remarkably good, not even teledisk could copy it properly, all my copies detected as copy.
Does anyone know what Contra copy did? and would KF be able to copy it today?
Thanks.

[brightcaster]

It's still available at http://www.alkonost.com/contracopy/ but it's not free and I can't find any button to download a demo. So can't say much...

David

[brightcaster]

I found the Demo-Version on another place at https://torry.net/authorsmore.php?id=5966 but it kicks off with an excepetion error on my Win98 machine with real fdc!

So sorry, I can't test it...

David

[brightcaster]

It runs on a friends WinXP computer so far. And It writes some obscure pattern to track 1 side 0 which I guess is the protection.

But even the original floppy is recognized as "no original keydisk" on this machine! So I can't check it against a simple rewrite of the raw-stream...

David

[hyperactive]

Maybe your floppy drive is out of alignment.
I could test it on my system with a couple of other floppy copiers I have here.
David Dunfield's image disk tools to name one of them.
Cheers.

[brightcaster]

There are 32 overlapping sectors on track 1 side 0. Easy to write with a sector orientated controller but impossible to read with all it contents. So yes you can't copy that with any WD controller.

But it should be no problem for a track orientated controller like kryoflux. Tested it on a WinXP Laptop with inbuild floppy drive and it did'nt do the trick! The original floppy tells me: "This is the Original Diskette!" but the copy says me "Please Wait" till I stop the test...

Yes, and in the HxC track analyzer both floppies look very different on track 1 side 0.

I guess this is the time where real experts are in need...


David

[hyperactive]

Can we run a floppy emulator and get it to write to track1s1 in a virtual image, just to see how the tracks are laid out?
Cheers.

[brightcaster]

That's how it looks in the HxC Analyzer...

David

[mr.vince]

But it should be no problem for a track orientated controller like kryoflux. Tested it on a WinXP Laptop with inbuild floppy drive and it did'nt do the trick! The original floppy tells me: "This is the Original Diskette!" but the copy says me "Please Wait" till I stop the test...

I am tempted to say that this rewrite is being made directly from a raw dump. But this kind of protection very likely needs some tweaking to how the data is read to write it in a way that it'll come back as expected. In other words... whenever something reads back differently than it was written, source data needs tweaking. Like for e.g. weak bits, where the pattern written will always generate different readouts.