[sebhc] H17 ROM and disk info

[Dwight K. Elvey]

>From: "Dave Dunfield" <dave04a at dunfield.com>
---snip---
>
>I am also a bit concerned that the H17 ROM provides quite a few vectors which
>are entry points for very low level/H17 specific functions (Move ARM in/out, 
wait
>for Hole, wait for Sync etc.) - These function would make no sense on the 
virtual
>disk contrller described above - Does HDOS use any of these functions?
>
Hi Dave
 I think these still can be dealt with in the emulator.
Moving the heads is just moving the offest in the
simulated disk's file. I believe one can determine ccomplete
actions from the port activity. One should even need to
know what routine called them in the ROM, OS or application.
One could make a simulated disk with complete sectors and
headers. Went looking at how the H17 controller talks to the
disk, One can recognize track stepping and also searches
for sector holes.
 Don't try to understand the software of the ROM, just look
at the port hardware and don't assume that there is anything
other than a maximum of XX number of bytes allowable between
index marks. Also that index marks are spaced timewise around
the disk, as well as bit spacewise.
 This way, you should eb able to handle any kind of funny
software protect or whatever might be on any particular disk
image.
Dwight


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