[Coco] Re: NitrOS9 on MESS?
Roger Taylor
rtaylor at bayou.com
Fri Dec 5 00:16:00 EST 2003
At 07:55 PM 12/4/2003 -0500, you wrote:
>The controller reports the passing of the floppy disk index hole past the
>drive detector as a bit in Status for type I commands. It also would be
>used by the Western Digital controller to synchronize read/writes in some
>fashion.
>
>The only time this info was used in Coco code was in programs that tested
>drive rotational speed. So, it would be invisible to Disk Basic or OS-9.
>
>It might be an issue with the MESS emulation of the controller. It would
>be most likely to show up in NitrOS-9 operations because of tighter timing
>during disk I/O. However, the bug in question does not depend on the
>floppy controller and is also present in .vhd use.
One of my first ever low-level disk drive experiments was to watch the
index sensor bit change states by reading a register. I think it was
65352? If it is, then my memory isn't bad at all since it's been about 15
years. :)
{Roger Taylor}
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