[Coco] Re: NitrOS9 on MESS?

[Nathan Woods]

Robert Gault 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.

Its very possible that MESS's emulation of this particular feature might 
be lacking.  Who knows, maybe NitrOS-9 attempts to perform this 
particular (or a similar) check and NitrOS-9 gets some weird result that 
it wasn't prepared to handle, and caching goes all to hell.  Interesting 
hypothesis; but at this point it is nothing more than a hypothesis.