SuperCard Pro Flux Image format (.scp)
#6
Thanks for the info. Yes, I believe there is some terminology difference here. This is what we called strongbits for the Amiga, and I am pretty sure that Turrican used this protection for the Amiga as well. We could duplicate it without hardware though because the Amiga's disk controller was so versatile. The more I read about the Atari ST stuff, the more I realize why we sold so many SuperCard Ami units to the Atari ST clubs. They used it with an Amiga 500 to duplicate all of the ST disks. Until the SuperCard Pro project, I had never seen a decoded MFM track (PC or Atari ST). I have always looked at everything as raw MFM (or flux since SuperCard Pro). I can see why you guys had your hands full. I worked at Central Point Software for awhile, writing Copy II 64/128 and I chatted quite a bit with the guy who was writing Copy II ST. He said it was a nightmare dealing with the WD1772 (which I later had to use with the Commodore 1571 and 1581 drives), and he was right! You were in a box without much control.

I did buy Turrican from the U.K. Hopefully it is the correct version, and I can test it with SuperCard Pro. Dungeon Master and Chaos Strikes Back copy just fine, and I am not altering any data from the data that is read - not even a normalization (write precomp) at this point, and the fuzzy bits are duplicated perfectly.

If strongbits are in fact a series of super fast transitions, then SuperCard Pro should be able to duplicate them. I believe I have the flux threshold set for 475ns. This means flux transitions can be this short before considered invalid. I realize that the idea behind the "no flux area" is that fact that the hardware's pulse detector can't do the normal return to zero, but there are drives (most PC drives) that don't have a problem showing the short pulses.
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SuperCard Pro Flux Image format (.scp) - by admin - 11-01-2013, 05:54 PM
RE: SuperCard Pro Flux Image format (.scp) - by admin - 12-19-2013, 05:44 PM



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