[HN Gopher] Weak bits floppy disc protection: an alternate origi...
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       Weak bits floppy disc protection: an alternate origins story on
       8-bit
        
       Author : scarybeast
       Score  : 19 points
       Date   : 2020-06-27 21:08 UTC (1 hours ago)
        
 (HTM) web link (scarybeastsecurity.blogspot.com)
 (TXT) w3m dump (scarybeastsecurity.blogspot.com)
        
       | dunham wrote:
       | It's much simpler than weak bits, but I remember one of the
       | Ultima games for DOS had a track with a small sector embedded in
       | the middle of a long sector. So from the point of view of the
       | controller after decoding, there were more sectors than could be
       | written onto a track.
       | 
       | All the copy protection did was decrypt itself, read the starting
       | address of the executable from a sector on that track, and jump
       | to it. My fix was to just stuff that address back into the
       | executable header. (I had actually purchased the game, I was just
       | tired of having to insert the floppy every time I ran it off of
       | the hard drive.)
        
       | mrlonglong wrote:
       | Fabulous explanation of how they did copy protection in the old
       | days. I remember the 8271 well. I'm not sure why they used such
       | an old chip with the BBC B, as it was quite expensive. The WD1770
       | was better and cheaper.
        
         | mrlonglong wrote:
         | I preferred the NEC uPD765 though. Higher density.
        
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       (page generated 2020-06-27 23:00 UTC)