On Aug 20, 2022, at 6:09 PM, Mark Garlanger <garl...@gmail.com> wrote:
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A lot of work Mark. Thanks for taking this on.
A few suggestions:
The Overview section would be more balanced if it explained exactly when the .h17disk format is needed, vs the H8D. H8D has many good practical uses and we already have hundreds of disks in this format. It meets the needs of many uses including the H89LDR program, Les Bird’s H89 emulator, and the JUKEBOX. Just having the H8D information often serves the purpose. But it *does* throw out information that would be useful or important from an archival perspective or if we ever wanted to exactly reproduce a disk. I don’t know if any manufacturers used disk copy protection but that might also be something that could be captured by .h17disk. I don’t foresee us converting all the existing H8Ds to h17disks so the two will probably coexist for some time. It makes sense, where possible, to capture any new disks we find in the more complete h17disk format.
I am concerned that the current format is not robust enough in the face of bit errors. It’s true we’ve come to think of disk storage as highly reliable, but if a bit or byte is lost I’m concerned about how to detect (or even correct). If this is truly an archival format then we should account for that. I suggest adding a CRC to each block. The H8/H89 even already have a very good CRC routine in the ROM (routine at 0x02E7; checksum maintained at 0x2017).
A few other nits I highlighted in my copy
Good work!
Glenn
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On Aug 28, 2022, at 2:21 AM, Mark Garlanger <garl...@gmail.com> wrote:
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