Problems writing back to floppy disk

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robbo007
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Joined: Wed May 23, 2012 2:56 pm
Location: Spain

Re: Problems writing back to floppy disk

Post by robbo007 »

mr.vince wrote: Fri Jun 12, 2020 11:38 am You could also re-format the raw streams to juggle the data in the track as needed to move the write splice to the write splice. Since we generate one file for each track, it should be easy to re-format and exchange.
Could you give me an example how to do this? Thanks.
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mr.vince
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Joined: Tue Oct 05, 2010 5:48 pm

Re: Problems writing back to floppy disk

Post by mr.vince »

Yes, you write e.g. a Python script, and rotate the raw data within the track and as a result place the write splice where you think it should be.
SomeGuy
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Re: Problems writing back to floppy disk

Post by SomeGuy »

Is there an existing Python module or library for interfacing with the raw files, or are you saying the format is simple enough to modify directly? Haven't had a chance to look at the file format but it does not sound too complicated.

Is there a way to tell the kryoflux to start writing at someplace besides the index? The thing with PC disks is that if a sector crosses the index, the FDC may not be able to read it.

I think HxC can also rotate tracks with its editor tools, but I don't know how well that works.

It would be nice to know exactly what the copy protection code is actually doing, but I don't have time to dig in to that myself.

The way the protection is laid out, I have wondered if it could detect a splice anywhere on the track. But the weird thing is there appears to be breaks at the beginning and end of each sector (in other words, the track was not written all at once) and even the protected bits look like they may have been written after the rest of the track. But that would have to be very timing sensitive, which is more than a real FDC can really do I think, and the bit of fuzing with PCE made it look like the protection was not trying to be that exact.

Have not had time to mess with this any more lately.
robbo007
Posts: 89
Joined: Wed May 23, 2012 2:56 pm
Location: Spain

Re: Problems writing back to floppy disk

Post by robbo007 »

I've managed to successfully duplicate this disk and its copy protection back to floppy using Transcopy 3.0 and an option board. Central Point Software mentions in an amended document to their manual, that when one is having problems with Softguard SuperLok v3.00 copy protection make sure you disable the option "copy across index".

@Someguy, This could be what your talking about the "splice" and copying across the index. In the case of Voyetra's Sequencer Plus MKI using Softguard SuperLok v3.00 Kit copy protection, this obviously affects it. I guess Transcopy had all the copy protection schemes pretty much worked out and integrated in their software making duplicating relatively easy. Seems Alan Silver was the man and still is... or was... :ugeek:

Would be good to see this copy protection scheme or something simular to the "copy across index" added to DTC making write back easier.

On a side note these dumps via transcopy 3.0 and the option board work perfectly with DOSBoxTC when mounted as a floppy image. Great note for the emulation side of things.
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