[sebhc] H8D files and labels

Dave Dunfield dave06a at dunfield.com
Tue Mar 28 05:23:15 CST 2006


> If you are going to go modifying the format, I'd suggest a more extensive
> modification that would allow for an arbitrary length and content of the
> "comment" ... even to the point that the "comment" could contain, for
> example, a JPEG file (photo of the original disk label).  Also, try to
> devise a technique that does this while allowing for backward compatibility,
> which probably means put the "comment" field at the end, not the beginning.

Oh well ... the idea is that it would have been a VERY simple modification to
implement in the simulators (scan for ^Z ad beginning - add offset to seeks).
Embeddeding JPEGs is beyond what I am interested in doing in my H8 tools
(DOS based).

Also, as noted in my original idea - it would be backward compatible.

The simulator checks the size now - so all that is needed is to slightly
expand this logic:

  if(size < RAW_IMAGE_SIZE)
    error("Bad disk image");
  else if(size == RAW_IMAGE_SIZE)
   offset = 0;
  else {
    offset = position_of_first(0x1A);
    if((size - offset) != raw_image_size)
      error("Bad disk image"); }

Also as noted, the whole point of putting the comment as text
terminated with ^Z is that you can simply TYPE the file to view
the comment (Try that with one of my ImageDisk .IMD files)
no special tools needed.

Dave

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dave06a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Collector of vintage computing equipment:
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