[sebhc] H17 ROM and disk info

[Dave Dunfield]

Hi Steven,

You didn't mention my original question/confirmation, so I assume it is correct
that are basically 2 blocks (with SYNC & CRC) for every physical sector on the
disk?

>I'm not even sure how to be purely generic about it anyway, since an OS (or 
>a custom driver) could change stuff like the number of sectors, the 
>size/format/presence of sector headers, the relationship between sectors and 
>holes, or even disregard holes entirely.

Yeah - it would be touch. You would have to basically record "tracks" which
would be the longest series of data that you could place on a physical track,
and include hold indications at the set spacing ... For most applciations,
the software would not actually use all of the possible bytes between holes,
and some would be wasted - but it would emulate the physical disk quite
well.


>I wasn't expecting that you'd need to spend any time with the 
>parameter-driven driver to figure out how to handle emulation.  I think the 
>low-level functions (that it calls anyway) should show you everything 
>important.  I was thinking the trickiest part of the emulation would be 
>satisfying the timing expectations in the driver (time between holes, holes 
>and data, etc).

I wanted parameter info so that I could figure out the parameters to the
individual functions, so I have a better understanding of what they are doing
as I try to reverse engineer them  - but I can probably get that from the listing
- Assuming it downloaded OK - I left it downloading this morning and have not
checked on it yet (will do now).

Again, thanks for all your help.

Regards,
Dave
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dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Vintage computing equipment collector.
                http://www.parse.com/~ddunfield/museum/index.html

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