[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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