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    SubjectRe: Copy protection of the floppies
    Hi,

    I don't believe in copy protection at all because what your program can read,
    other programs can read, and what your program can test, others can trick it
    into not testing it anymore.

    However, there was a solution that I found clever : the weak bit. Basically,
    a floppy was written with a special controller, and one sector had invalid
    states that could randomly be read either 0 or 1 by the drive. The software
    then tried to read the same sector 10 times and expected the contents to
    change due to the controller's inability to identify the data as clear 0 or 1.
    A copy of the floppy would definitely fix the contents to what was read at the
    copy time, so the software would not see any more changes during its read test
    and would conclude that it was a copy.

    I'm not certain that this was fully compatible with all drives and/or
    controllers, because there's always a risk of some hardware always reporting
    0's or 1's on this sector, but I found the concept original.

    Of course, it took the editor far more time to develop this solution than the
    crackers to "fix" the software. You know, launch debug, replace the offending
    JZ with a JMP or with a NOP/NOP...

    Sincerely, I don't think you want to spend so much time developping something
    which can be broken within a few minutes.

    Regards,
    Willy

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