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Atari demoscene BBS
 
Re: Easy words for boot sector ?
Posted by: Alien / ST-CNX Mar,31.2017-20:21 

For what it's worth I don't agree with the 480 byte rule you seem to be using.

The rule democoders used was: is it 512 bytes long, and when placed on sector 0 of track 0 of a floppy disk, does the Atari ST boot into it? The exact requirements to achieve this can be recovered by disassembling / reading the source code for the TOS. Atari's documentation sometimes said "do things this way", but if their code didn't enforce that rule we didn't necessarily follow it.

For instance, if a demo contained its own disk copying software, it did not need to be compatible with other disk-copiers, and therefore could ditch the metadata another disk copy tool might need. That's a very simple way to protect a disk.

We didn't do everything by the book. For instance the actual requirement was for the sum of words in the bootsector to be $1234 (IIRC) but not for the last word to be a "checksum". You could put code in there, if you wanted, and put the checksum somewhere else (like the metadata). Similarly other code or data might fit into space reserved for the metadata TOS didn't need to boot.




[All messages in this thread]

Topic Posted by  Date 
Easy words for boot sector ? s_t_s Mar,15.2017-10:35
  Re: Easy words for boot sector ? ggn Mar,15.2017-10:54
    Re: Easy words for boot sector ? s_t_s Mar,15.2017-11:24
      Re: Easy words for boot sector ? ggn Mar,15.2017-14:30
      Re: Easy words for boot sector ? evil Mar,15.2017-19:30
        Re: Easy words for boot sector ? s_t_s Mar,17.2017-09:36
          Re: Easy words for boot sector ? leonard Mar,18.2017-23:04
            Re: Easy words for boot sector ? s_t_s Mar,21.2017-23:01
              Re: Easy words for boot sector ? leonard Mar,22.2017-02:28
                Re: Easy words for boot sector ? ggn Mar,23.2017-10:29
            Re: Easy words for boot sector ? PeyloW Mar,24.2017-23:23
  Re: Easy words for boot sector ? s_t_s Mar,15.2017-11:17
  Re: Easy words for boot sector ? Alien / ST-CNX Mar,24.2017-07:35
    Re: Easy words for boot sector ? s_t_s Mar,24.2017-19:59
      Re: Easy words for boot sector ? Alien / ST-CNX Mar,25.2017-01:04
    Re: Easy words for boot sector ? PeyloW Mar,25.2017-20:04
      Re: Easy words for boot sector ? ggn Mar,26.2017-17:55
      Re: Easy words for boot sector ? Leonard Mar,27.2017-01:39
        Re: Easy words for boot sector ? ggn Mar,27.2017-07:36
          Re: Easy words for boot sector ? s_t_s Mar,28.2017-19:38
            Re: Easy words for boot sector ? ggn Mar,29.2017-07:47
              Re: Easy words for boot sector ? s_t_s Mar,29.2017-10:26
                Re: Easy words for boot sector ? s_t_s Mar,29.2017-10:27
                Re: Easy words for boot sector ? ggn Mar,30.2017-07:56
                  Re: Easy words for boot sector ? s_t_s Mar,30.2017-09:02
                    Re: Easy words for boot sector ? Alien / ST-CNX Mar,31.2017-20:21
                  Re: Easy words for boot sector ? s_t_s Mar,30.2017-09:04


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