1.44M floppy on Color Computer (was Re: Ebay reaches new low)

From: Dwight Elvey <elvey_at_hal.com>
Date: Tue Nov 9 19:58:19 1999

Eric Smith <eric_at_brouhaha.com> wrote:
> Roger Merchberger <zmerch_at_30below.com> wrote:
> > P.S. To keep this on-topic, does anyone have instructions on the hack to
> > convert the above-mentioned floppy controller to be able to handle 3.5" HD
> > floppy drives? I'd *love* to have a 1.44Meg floppy formatted under OS/9...
> > :-) Also, is there any way (without reconstructing the 6 million dollar
> > man...) to get two floppy controllers online using the MultiPak?
>
> Even if you hack the FD controller's clock and data separator, it's possible
> that the OS/9 floppy driver may not be able to handle the data rate of a
> 1440K floppy, which is 500 Kbps vs. the 250 Kbps of the drives it was
> intended for. That's a byte every 16 microseconds, which is tricky
> with no DMA or FIFO, since you have to poll for the FDC to be ready for
> each byte.
>
> I was disappointed to find that the optional floppy controller board
> for the AIM-65 can support 8 inch double density operation (which has
> the same data rate as the 1440K floppy) only with the addition of another
> board with a DMA controller. Which, of course, I don't have. I'm not
> sure that Rockwell even made it.

Hi
 If you ignore errors and just deal with the data transfer,
I'm almost sure a 6809 can keep up. It is just a matter
of counting the cycles carefully and not having any
extra operations.
Dwight
Received on Tue Nov 09 1999 - 19:58:19 GMT