[Coco] Question about MPI behavior

[Robert Gault]

Paulo Lindoso wrote:
> If memory serves, the reason why the drive controller must be in slot 4 was
> bus timing of sorts.
>
> I remember reading somewhere (Rainbow, list...) that if you used the
> controller in another slot, you might get intermitent problems due to
> timing problems;  it kinda makes sense for low-frequency circuits such as
> the CoCo, but I have never tested it myself.
>

Could be, but more likely Tandy authors and other third party authors did not 
want to write software to determine which slot contained an FDC. Also if more 
than one was present, how would an author know which to select?

Slot 4 became the default/defacto slot for FDCs. Given the wide range of Basic 
ml and OS-9 programs, having a default slot makes sense.