[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.


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

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