On Mon, May 13, 2019 at 2:24 PM didier derny <didier_at_aida.org> wrote: > I saw a software, "silicon office", with a copy protection using a specific piece of code loaded in the 8050/8250 to read a specific track > I dont remember exactly but they changed something in the format of this special track > so if it was not read with their specific routine it failed or if the special track was altered by a standard copy > > the code was quite short and put in place with memory write / memory read / memory execute > > I guess this system was used by several companies... There are a number of copy protection tricks described (with example code) for the 1541 in Chapter 7 of "Inside Commodore DOS" (https://www.pagetable.com/docs/Inside%20Commodore%20DOS.pdf) but the same general techniques, with slightly different implementations, hold across any of the Commodore diskette drives. Having their own CPU (or two), these drives are insanely flexible. -ethanReceived on 2020-05-29 21:20:14
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